| 1. |
- Simoff, Ivailo, et al.
(författare)
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Complete Knockout of Endogenous Mdr1 (Abcb1) in MDCK Cells by CRISPR-Cas9
- 2016
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Ingår i: Journal of Pharmaceutical Sciences. - 0022-3549 .- 1520-6017. ; 105:2, s. 1017-1021
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Tidskriftsartikel (refereegranskat)abstract
- Madin-Darby canine kidney II cells transfected with one or several transport proteins are commonly used models to study drug transport. In these cells, however, endogenous transporters such as canine Mdr1/P-glycoprotein (Abcb1) complicate the interpretation of transport studies. The aim of this investigation was to establish a Madin-Darby canine kidney II cell line using CRISPR-Cas9 gene-editing technology to knock out endogenous canine Mdr1 (cMdr1) expression. CRISPR-Cas9-mediated Abcb1 homozygous disruption occurred at frequencies of around 20% and resulted in several genotypes. We selected 1 clonal cell line, cMdr1 KO Cl2, for further examination. Consistent with an on-target effect of CRISPR-Cas9 in specific regions of the endogenous canine Abcb1 gene, we obtained a cell clone with Abcb1 gene alterations and without any cMdr1 expression, as confirmed by genome sequencing and quantitative protein analysis. Functional studies of these cells, using digoxin and other prototypic MDR1 substrates, showed close to identical transport in the apical-to-basolateral and basolateral-to-apical directions, resulting in efflux ratios indistinguishable from unity.
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| 2. |
- Ahnfelt, Emelie, et al.
(författare)
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In Vitro Release Mechanisms of Doxorubicin From a Clinical Bead Drug-Delivery System
- 2016
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 105:11, s. 3387-3398
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Tidskriftsartikel (refereegranskat)abstract
- The release rate of doxorubicin (DOX) from the drug-delivery system (DDS), DC Bead, was studied by 2 miniaturized in vitro methods: free-flowing and sample reservoir. The dependencies of the release mechanisms on in vitro system conditions were investigated experimentally and by theoretical modeling. An inverse relationship was found between release rates and bead size, most likely due to the greater total surface area. The release rates correlated positively with temperature, release medium volume, and buffer strength, although the release medium volume had larger effect than the buffer strength. The sample reservoir method generated slower release rates, which described the in vivo release profile more accurately than the free-flowing method. There was no difference between a pH of 6.3 or 7.4 on the release rate, implying that the slightly acidic tumor microenvironment is less importance for drug release. A positive correlation between stirring rate and release rate for all DDS sizes was observed, which suggests film controlled release. Theoretical modeling highlighted the influence of local equilibrium of protonation, self-aggregation, and bead material interactions of DOX. The theoretical release model might describe the observed larger sensitivity of the release rate to the volume of the release medium compared to buffer strength. A combination of miniaturized in vitro methods and theoretical modeling are useful to identify the important parameters and processes for DOX release from a micro gel-based DDS.
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| 3. |
- Albrecht, Karin, et al.
(författare)
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In Vivo Investigation of Thiomer-Polyvinylpyrrolidon Nanoparticles Using Magnetic Resonance Imaging
- 2010
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Ingår i: Journal of Pharmaceutical Sciences. - : Wiley Inter Science. - 0022-3549 .- 1520-6017. ; 99:4, s. 2008-2017
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Tidskriftsartikel (refereegranskat)abstract
- This study focused on the investigation of the permeation enhancing effects of a stomach targeted, nanoparticulate drug delivery system. The polyacrylic acid–cysteine/polyvinylpyrrolidon nanoparticles were loaded with the magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium( III)dihydrogen salt (Gd-DTPA). Average particle size was determined to be 130nm and the optimum for stability was found to be below a pH of 4.5. In vitro permeation studies were performed on rat gastric mucosa and revealed an eightfold increase in Gd- DTPA uptake when incorporated in the nanoparticles compared to evaluation in the presence of unformulated polyacrylic acid–cysteine. In vivo investigations with rats were performed via the noninvasive MRI method in order to track the nanoparticles way through the gastrointestinal tract. When Gd-DTPA was administered orally as nanoparticulate suspension, an increased MRI signal in the urinary bladder was detected after 34 min, providing evidence for systemic uptake and renal elimination of the contrast agent. As control experiments with Gd-DTPA only or in combination with unformulated polyacrylic acid–cysteine revealed no MRI signal increase at all, the significant permeation enhancing effect could be identified based on the nanoparticulate formulation.
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| 4. |
- Alhalaweh, Amjad, et al.
(författare)
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Molecular Drivers of Crystallization Kinetics for Drugs in Supersaturated Aqueous Solutions
- 2019
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Ingår i: Journal of Pharmaceutical Sciences. - : ELSEVIER SCIENCE INC. - 0022-3549 .- 1520-6017. ; 108:1, s. 252-259
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we explore molecular properties of importance in solution-mediated crystallization occurring in supersaturated aqueous drug solutions. Furthermore, we contrast the identified molecular properties with those of importance for crystallization occurring in the solid state. A literature data set of 54 structurally diverse compounds, for which crystallization kinetics from supersaturated aqueous solutions and in melt-quenched solids were reported, was used to identify molecular drivers for crystallization kinetics observed in solution and contrast these to those observed for solids. The compounds were divided into fast, moderate, and slow crystallizers, and in silico classification was developed using a molecular K-nearest neighbor model. The topological equivalent of Grav3 (related to molecular size and shape) was identified as the most important molecular descriptor for solution crystallization kinetics; the larger this descriptor, the slower the crystallization. Two electrotopological descriptors (the atom-type E-state index for -Caa groups and the sum of absolute values of pi Fukui(+) indices on C) were found to separate the moderate and slow crystallizers in the solution. The larger these descriptors, the slower the crystallization. With these 3 descriptors, the computational model correctly sorted the crystallization tendencies from solutions with an overall classification accuracy of 77% (test set).
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| 5. |
- Alvarsson, Jonathan, 1981-, et al.
(författare)
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Predicting With Confidence : Using Conformal Prediction in Drug Discovery
- 2021
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 110:1, s. 42-49
-
Forskningsöversikt (refereegranskat)abstract
- One of the challenges with predictive modeling is how to quantify the reliability of the models' predictions on new objects. In this work we give an introduction to conformal prediction, a framework that sits on top of traditional machine learning algorithms and which outputs valid confidence estimates to predictions from QSAR models in the form of prediction intervals that are specific to each predicted object. For regression, a prediction interval consists of an upper and a lower bound. For classification, a prediction interval is a set that contains none, one, or many of the potential classes. The size of the prediction interval is affected by a user-specified confidence/significance level, and by the nonconformity of the predicted object; i.e., the strangeness as defined by a nonconformity function. Conformal prediction provides a rigorous and mathematically proven framework for in silico modeling with guarantees on error rates as well as a consistent handling of the models' applicability domain intrinsically linked to the underlying machine learning model. Apart from introducing the concepts and types of conformal prediction, we also provide an example application for modeling ABC transporters using conformal prediction, as well as a discussion on general implications for drug discovery.
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| 6. |
- Amidon, Gregory E., et al.
(författare)
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Fifty-Eight Years and Counting : High-Impact Publishing in Computational Pharmaceutical Sciences and Mechanism-Based Modeling
- 2019
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 108:1, s. 2-7
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Tidskriftsartikel (refereegranskat)abstract
- With this issue of the Journal of Pharmaceutical Sciences, we celebrate the nearly 6 decades of contributions to mechanistic-based modeling and computational pharmaceutical sciences. Along with its predecessor, The Journal of the American Pharmaceutical Association: Scientific Edition first published in 1911, JPharmSci has been a leader in the advancement of pharmaceutical sciences beginning with its inaugural edition in 1961. As one of the first scientific journals focusing on pharmaceutical sciences, JPharmSci has established a reputation for publishing high-quality research articles using computational methods and mechanism-based modeling. The journal’s publication record is remarkable. With over 15,000 articles, 3000 notes, and more than 650 reviews from industry, academia, and regulatory agencies around the world, JPharmSci has truly been the leader in advancing pharmaceutical sciences.
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| 7. |
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| 8. |
- Andersson, Sara B. E., et al.
(författare)
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Interlaboratory Validation of Small-Scale Solubility and Dissolution Measurements of Poorly Water-Soluble Drugs
- 2016
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 105:9, s. 2864-2872
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the interlaboratory variability in determination of apparent solubility (Sapp) and intrinsic dissolution rate (IDR) using a miniaturized dissolution instrument. Three poorly water-soluble compounds were selected as reference compounds and measured at multiple laboratories using the same experimental protocol. Dissolution was studied in fasted-state simulated intestinal fluid and phosphate buffer (pH 6.5). An additional 6 compounds were used for the development of an IDR measurement guide, which was then validated with 5 compounds. The results clearly showed a need for a standardized protocol including both the experimental assay and the data analysis. Standardization at both these levels decreased the interlaboratory variability. The results also illustrated the difficulties in performing disc IDR on poorly water-soluble drugs because the concentrations reached are typically below the limit of detection. The following guidelines were established: for compounds with Sapp > 1 mg/mL, the disc method is recommended. For compounds with Sapp <100 μg/mL, IDR is recommended to be performed using powder dissolution. Compounds in the interval 100 μg/mL to 1 mg/mL can be analyzed with either of these methods.
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| 9. |
- Asad, Shno, et al.
(författare)
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Proteomics-Informed Identification of Luminal Targets For In Situ Diagnosis of Inflammatory Bowel Disease
- 2021
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 110:1, s. 239-250
-
Tidskriftsartikel (refereegranskat)abstract
- Inflammatory bowel disease (IBD) is a chronic condition resulting in impaired intestinal homeostasis. Current practices for diagnosis of IBD are challenged by invasive, demanding procedures. We hypothesized that proteomics analysis could provide a powerful tool for identifying clinical biomarkers for non-invasive IBD diagnosis. Here, the global intestinal proteomes from commonly used in vitro and in vivo models of IBD were analyzed to identify apical and luminal proteins that can be targeted by orally delivered diagnostic agents. Global proteomics analysis revealed upregulated plasma membrane proteins in intestinal segments of proximal- and distal colon from dextran sulfate sodium-treated mice and also in inflamed human intestinal Caco-2 cells pretreated with pro-inflammatory agents. The upregulated colon proteins in mice were compared to the proteome of the healthy ileum, to ensure targeting of diagnostic agents to the inflamed colon. Promising target proteins for future investigations of non-invasive diagnosis of IBD were found in both systems and included Tgm2/TGM2, Icam1/ICAM1, Ceacam1/CEACAM1, and Anxa1/ANXA1. Ultimately, these findings will guide the selection of appropriate antibodies for surface functionalization of imaging agents aimed to target inflammatory biomarkers in situ.
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| 10. |
- Aziz, Mohd Yusmaidie, 1984, et al.
(författare)
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Inhibition of CYP3A by Antimalarial Piperaquine and Its Metabolites in Human Liver Microsomes With IVIV Extrapolation
- 2018
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549. ; 107:5, s. 1461-1467
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Tidskriftsartikel (refereegranskat)abstract
- The potential of the antimalarial piperaquine and its metabolites to inhibit CYP3A was investigated in pooled human liver microsomes. CYP3A activity was measured by liquid chromatography-tandem mass spectrometry as the rate of 1'-hydroxymidazolam formation. Piperaquine was found to be a reversible, potent inhibitor of CYP3A with the following parameter estimates (%CV): IC50 = 0.76 mu M(29), K-i = 0.68 mu M (29). In addition, piperaquine acted as a time-dependent inhibitor with IC50 declining to 0.32 mu M (28) during 30-min pre-incubation. Time-dependent inhibitor estimates were k(inact) = 0.024 min(-1) (30) and K-I = 1.63 mu M(17). Metabolite M2 was a highly potent reversible inhibitor with estimated IC50 and K-i values of 0.057 mu M (17) and 0.043 mu M (3), respectively. M1 and M5 metabolites did not show any inhibitory properties within the limits of assay used. Average (95th percentile) simulated in vivo areas under the curve of midazolam increased 2.2-fold (3.7-fold) on the third which is the last day of piperaquine dosing, whereas for its metabolite M2, areas under the curve of midazolam increased 7.7-fold (13-fold). (C) 2018 American Pharmacists Association (R). Published by Elsevier Inc. All rights reserved.
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| 11. |
- Backstrom, E., et al.
(författare)
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Possible Extraction of Drugs from Lung Tissue During Broncho-alveolar Lavage Suggest Uncertainty in the Procedure's Utility for Quantitative Assessment of Airway Drug Exposure
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:3, s. 852-858
-
Tidskriftsartikel (refereegranskat)abstract
- Following inhaled dosing, broncho-alveolar lavage (BAL) is often used for sampling epithelial lining fluid (ELF) to determine drug concentration in the lungs. This study aimed to explore the technique's suitability. Urea is typically used to estimate the dilution factor between the BAL fluid and physiological ELF, since it readily permeates through all fluids in the body. As representatives of permeable small molecule drugs with high, medium and low tissue distribution properties, propranolol, diazepam, indomethacin and AZD4721 were infused intravenously to steady state to ensure equal unbound drug concentrations throughout the body. The results showed that propranolol had higher unbound concentrations in the ELF compared to the plasma whilst this was not the case for the other compounds. Experiments with different BAL volumes and repeated lavaging indicated that the amount of drug extracted is very sensitive to experimental procedure. In addition, the results show that the unbound concentrations in ELF compared to plasma differs dependent on molecule class and tissue distribution properties. Overall data suggests that lavaging can remove drug from lung tissue in addition to ELF and highlights significant uncertainty in the robustness of the procedure for determining ELF drug concentrations. (c) 2021 American Pharmacists Association. Published by Elsevier Inc. All rights reserved.
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| 12. |
- Bengtsson, Jörgen, et al.
(författare)
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The use of a deuterated calibrator for in vivo recovery estimations in microdialysis studies
- 2008
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 97:8, s. 3433-3441
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Tidskriftsartikel (refereegranskat)abstract
- One of the crucial issues in quantitative microdialysis is the reliability of recovery estimates to correctly estimate unbound drug tissue concentrations. If a deuterated calibrator is used for retrodialysis, the calibrator has the same properties as the study drug. However, recovery of the calibrator may be affected by the presence of the drug in the tissues. The aim of this study was to investigate the recovery of deuterated morphine with time in the absence and presence of morphine in rat tissues. Microdialysis probes were placed in the brain and blood of eight rats. Ringer's solution containing D3-morphine was perfused throughout the study and recovery was estimated. After a stabilization period of 3 h, an exponential infusion of morphine was administered over 4 h. The presence of morphine did not affect the recovery of D3-morphine from brain or blood. The average recovery values (SD) were 0.145 (0.039) and 0.131 (0.048) during the stabilization and infusion periods, respectively, for the brain probe and 0.792 (0.055) and 0.790 (0.084), respectively, for the blood probe. The recovery of deuterated morphine was stable over time in the brain and in blood, and was not affected by the presence of pharmacologically concentrations of morphine.
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| 13. |
- Berg, Staffan, et al.
(författare)
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In Vitro and In Vivo Evaluation of 3D Printed Capsules with Pressure Triggered Release Mechanism for Oral Peptide Delivery
- 2021
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 110:1, s. 228-238
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Tidskriftsartikel (refereegranskat)abstract
- In this study a 3D printed capsule designed to break from the physiological pressures in the antropyloric region was evaluated for its ability to deliver the synthetic octapeptide octreotide in beagle dogs when co-formulated with the permeation enhancer sodium caprate. The pressure sensitive capsules were compared to traditional enteric coated hard gelatin capsules and enteric coated tablets. Paracetamol, which is completely absorbed in dogs, was included in the formulations and used as an absorption marker to give information about the in vivo performance of the dosage forms. The pressure sensitive capsules released drug in 50% of the dogs. In the cases where drug was released, there was no difference in octreotide bioavailability or C-max compared to the enteric coated dosage forms. When comparing all dosage forms, a correlation was seen between paracetamol C-max and octreotide bioavailability, suggesting that a high drug release rate may be beneficial for peptide absorption when delivered together with sodium caprate. (C) 2020 Published by Elsevier Inc.
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| 14. |
- Bergstrom, P. O., et al.
(författare)
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Crystal structure and physical properties of two polymorphs of ropivacaine HCl
- 2006
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 95:3, s. 680-688
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of two polymorphs of ropivacaine HCl have been determined, as well as their relative stability up to 100 degrees C. A geometric restriction for a solid-state transition between the two polymorphs has been identified. The packing density along the H-bonded chains form the basis for a model explaining the kinetic crystallization of the metastable form. The difference in stability and physicochemical properties between the two polymorphs can be attributed to the difference in crystal structure.
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| 15. |
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| 16. |
- Bogdanova, Ekaterina, et al.
(författare)
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Influence of Cooling Rate on Ice Crystallization and Melting in Sucrose-Water System
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier B.V.. - 0022-3549 .- 1520-6017. ; 111:7, s. 2030-2037
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Tidskriftsartikel (refereegranskat)abstract
- The ice crystallization and melting in systems where the equilibrium state is difficult to reach is one of the growing areas in pharmaceutical freeze-drying research. The quality of the final freeze-dried product depends on the parameters of the cooling step, which affect the ice nucleation and growth. In this paper, we present a DSC study of ice crystallization and melting in a sucrose-water system. Using two different types of thermal cycles, we examine the influence of cooling and heating rates on the thermal behavior of sucrose-water solutions with water contents between 50 and 100 wt%. The DSC results show that low cooling rates provide crystallization at higher temperatures and lead to lower amount of non-freezing water. Consequently, the glass transition and ice melting properties observed upon heating depend on the cooling conditions in the preceding step. Based on the experimental results, we investigate the reasons for the existence of the two steps on DSC heating curves in sucrose-water systems: the glass transition step and the onset of ice melting. We show that diffusion of water can be the limiting factor for ice growth and melting in the sucrose-water system when the amorphous phase is in a liquid state. In particular, when the diffusion coefficient drops below 10−14 m2/sec, the ice crystals growth or melting becomes strongly suppressed even above the glass transition temperature. Understanding the diffusion limitations in the sucrose-water system can be used for the optimization of the freeze-drying protocols for proteins and probiotics. © 2022 The Authors
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| 17. |
- Boissier, Catherine, 1972, et al.
(författare)
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Study of Pharmaceutical Coatings by Means of NMR Cryoporometry and SEM Image Analysis
- 2012
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 1520-6017 .- 0022-3549. ; 101:7, s. 2512-2522
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear magnetic resonance (NMR) cryoporometry and scanning electron microscopy (SEM) image analysis have been used to investigate the size and shape distribution of pores in pharmaceutical coatings. The coatings were made from a mixture of hydroxypropylcellulose (HPC) and ethylcellulose (EC). Upon solvent evaporation from a solution consisting of both the polymers, a solid polymer film is formed, which after removal of the water-soluble HPC consists of a skeleton of EC. A change in the amount of HPC enables modification of the water permeability through the films. By means of NMR cryoporometry, the presence of small pores (radius below 400 nm) was revealed with no significant change in the pore size distribution (PSD) as the HPC content in the films were changed. NMR cryoporometry showed the presence of channels of a characteristic 30-nm length scale in the films that contained more than 22% HPC. Below this threshold, the lack of interconnecting channels seems to prevent complete HPC dissolution and thereby the water permeability. SEM image analysis showed pore sizes that ranged from hundreds of nanometers up to few micrometers. Above the 22% threshold, further increase of HPC in the films resulted in an increased pore volume and wider PSD.
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| 18. |
- Boström, Emma, et al.
(författare)
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Oxycodone Pharmacokinetics and Pharmacodynamics in the Rat in the Presence of the P-Glycoprotein Inhibitor PSC833
- 2005
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 94:5, s. 1060-1066
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate the in vivo influence of the P-glycoprotein (P-gp) inhibitor PSC833 on the plasma pharmacokinetics, total brain concentrations and tail-flick latency of oxycodone in rats. Eight rats each received an infusion of PSC833 or vehicle without PSC833. One hour later, all animals received 0.3 mg/kg oxycodone as a 1-h infusion. Plasma samples were taken, and tail-flick latency was monitored during the infusion and for 2 h thereafter. The brains were collected at the end of the experiment. There were no differences between the two groups in area under the plasma oxycodone concentration-time curve from time zero to infinity, or oxycodone plasma clearance, volume of distribution at steady-state, or half-life. There were no differences in average total brain oxycodone concentrations at 180 min, nor were there any differences in average tail-flick latency for the PSC833 and control groups. In conclusion, coadministration of PSC833 did not alter the plasma pharmacokinetics, brain concentrations, or associated tail-flick latency of oxycodone, indicating that oxycodone is not a P-gp substrate in the rat. This has important clinical implications, as it indicates that oxycodone, unlike some other opioids, will not interact at the blood-brain barrier (BBB) with concomitantly administered P-gp substrates.
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| 19. |
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| 20. |
- Brenden, Nina, et al.
(författare)
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A triple-transgenic immunotolerant mouse model.
- 2013
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 102:3, s. 1116-24
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Tidskriftsartikel (refereegranskat)abstract
- Avoiding unwanted immunogenicity is of key importance in the development of therapeutic drug proteins. Animal models are of less predictive value because most of the drug proteins are recognized as foreign proteins. However, different methods have been developed to obtain immunotolerant animal models. So far, the immunotolerant animal models have been developed to assess one protein at a time and are not suitable for the assessment of combination products. Our aim was to develop an animal model for evaluating the impact of manufacturing and formulation changes on immunogenicity, suitable for both single protein and combination products. We constructed two lines of transgenic mice expressing the three human coagulation factors, II, VII, and X, by inserting a single vector containing the three coagulation factors encoding sequences separated by insulator sequences derived from the chicken beta-globin locus into the mouse genome. Immunization of transgenic mice from the two lines and their wild-type littermates showed that transgenic mice from both lines were immunotolerant to the expressed human coagulation factors. We conclude that transgenic mice immunotolerant to multiple proteins can be obtained, and that these mice are potentially useful as animal models in the assessment of immunogenicity in response to manufacturing changes.
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| 21. |
- Brohede, Ulrika, et al.
(författare)
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Characterization of the drug release process by investigation of its temperature dependence
- 2004
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 93:7, s. 1796-1803
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Tidskriftsartikel (refereegranskat)abstract
- Temperature-dependent drug release from disintegrating tablets made of NaCl-containing agglomerated micronized cellulose (AMC) granules has been studied to characterize the release process. Release measurements on tablets compacted at three different compaction pressures; 50, 100, and 200 MPa, were performed at seven different temperatures; 6, 23, 33, 43, 50, 55, and 63°C using the recently developed alternating ionic current method. Tablets compacted at different compaction pressures showed similar release rates. The release process was found to be diffusion-controlled, and the activation energy of the diffusion coefficient was comparable to that obtained for diffusion in pure water. The results show that the AMC granules in contact with water swell to a size and shape that is only slightly affected by their compaction history and the ion diffusion operates mainly within liquid-filled pores within the AMC granules. By using the temperature dependence of the release process, it was possible to reach this conclusion without any assumptions concerning the number and radii of the granules into which the tablets disintegrated. Further, the magnitude of the effective diffusion coefficient was found to be ∼7.5 · 10−10 cm2/s, which is ∼four orders of magnitude lower than for unhindered diffusion of Na+ and Cl− in water but similar to the diffusion coefficient for protons and OH− ions in microcrystalline cellulose.
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| 22. |
- Brohede, Ulrika, et al.
(författare)
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Percolative drug diffusion from cylindrical matrix systems with unsealed boundaries
- 2007
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 96:11, s. 3087-3099
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Tidskriftsartikel (refereegranskat)abstract
- Release of NaCl in both the axial and radial directions from cylindrical ethyl cellulose tablets were investigated by the alternating ionic current method. The pore structure of the investigated binary mixtures was examined by mercury porosimetry and scanning electron microscopy, and the nm range fractal surface dimension of tablet pore walls was extracted from krypton gas adsorption isotherms. The drug release was shown to consist of two overlapping processes of which the first was ascribed to dissolution of NaCl close to the tablet boundary followed by subsequent diffusion through a thin ethyl cellulose layer and a second from which a porosity percolation threshold of 0.22 could be extracted. As well, a cross-over to effective-medium behaviour at a porosity of 0.44 was observed. The presented findings showed that drug release from matrix tablets with unsealed tablet walls substantially differs from earlier investigated release processes for which the drug has only been allowed to escape through one of the flat tablet surfaces. Thus, the present study brings forward knowledge important for the tailoring of controlled drug delivery vehicles with optimum release patterns.
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| 23. |
- Bylund, Johan, 1970-, et al.
(författare)
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Presystemic metabolism of AZ'0908, a novel mPGES-1 inhibitor : An in vitro and in vivo cross-species comparison.
- 2013
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 102:3, s. 1106-1115
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Tidskriftsartikel (refereegranskat)abstract
- AZ'0908 is a novel microsomal prostaglandin E synthase-1 inhibitor intended for oral administration. Pharmacokinetic experiments in rats showed that bioavailability was much lower than anticipated and increased following pretreatment with the nonspecific cytochrome P450 (CYP) inhibitor 1-aminobenzotriazole, presumably by inhibition of intestinal metabolism. Stability experiments in rat liver and intestinal fractions revealed that the intrinsic clearance (Cl(int) ) was much higher in intestinal than in liver microsomes. Caco2 experiments showed that AZ'0908 was a substrate for breast cancer resistance protein. Permeability was generally high and the efflux component was saturable predicting good absorption. The Cl(int) values in human intestinal microsome and S9 fractions were low. A correlation occurred between in vitro intestinal metabolism and in vivo intestinal loss in rats and dogs. Enzyme identification experiments showed that human CYP2J2 was involved in the oxidation of AZ'0908. In rats, the major metabolic enzyme was not identified. However, rat CYP2J2 analogs were not investigated. Intestinal metabolism appeared to be a major occurrence, explaining intestinal loss of AZ'0908 in the rats. In view of good overall permeability, low in vitro intestinal turnover, and relative low intestinal abundance of CYP2J2, we predict that intestinal metabolism of AZ'0908 in human does not exert a major issue.
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| 24. |
- Bäckström, Erica, et al.
(författare)
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Development of a Novel Lung Slice Methodology for Profiling of Inhaled Compounds
- 2016
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 105:2, s. 838-845
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Tidskriftsartikel (refereegranskat)abstract
- The challenge of defining the concentration of unbound drug at the lung target site after inhalation limits the possibility to optimize target exposure by compound design. In this study, a novel rat lung slice methodology has been developed and applied to study drug uptake in lung tissue, and the mechanisms by which this occurs. Freshly prepared lung slices (500 μm) from drug-naive rats were incubated with drugs followed by determination of the unbound drug volume of distribution in lung (Vu,lung), as the total concentration of drug in slices divided by the buffer (unbound) concentration. Vu,lung determined for a set of inhaled drug compounds ranged from 2.21 mL/g for salbutamol to 2970 mL/g for dibasic compound A. Co-incubation with monensin, a modulator of lysosomal pH, resulted in inhibition of tissue uptake of basic propranolol to 13%, indicating extensive lysosomal trapping. Partitioning into cells was particularly high for the cation MPP+ and the dibasic compound A, likely because of the carrier-mediated transport and lysosomal trapping. The results show that different factors are important for tissue uptake and the presented method can be used for profiling of inhaled compounds, leading to a greater understanding of distribution and exposure of drug in the lung.
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| 25. |
- Bäckström, Erica, et al.
(författare)
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Lung Retention by Lysosomal Trapping of Inhaled Drugs Can Be Predicted In Vitro With Lung Slices
- 2016
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 105:11, s. 3432-3439
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Tidskriftsartikel (refereegranskat)abstract
- Modulating and optimizing the local pharmacokinetics of inhaled drugs by chemical design or formulation is challenged by the lack of predictive in vitro systems and in vivo techniques providing a detailed description of drug location in the lung. The present study investigated whether a new experimental setup of freshly prepared agarose-filled lung slices can be used to estimate lung retention in vitro, by comparing with in vivo lung retention after intratracheal instillation. Slices preloaded with inhaled beta-adrenergic compounds (salbutamol, formoterol, salmeterol, indacaterol or AZD3199) were incubated in a large volume of buffer (w/wo monensin to assess the role of lysosomal trapping), and the amount remaining in slices at different time points was determined with liquid chromatography-tandem mass spectrometry. The in vitro lung retention closely matched the in vivo lung retention (half-lives within 3-fold for 4/5 compounds), and monensin shortened the half-lives for all compounds. The results suggest that freshly prepared rat lungs slices can be used to predict lung retention and that slow kinetics of lysosomal trapping is a key mechanism by which retention in the lung and the effect duration of inhaled beta-adrenergic bronchodilators are prolonged.
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| 26. |
- Cappelletto, Elia, et al.
(författare)
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Impact of Post Manufacturing Handling of Protein-Based Biologic Drugs on Product Quality and User Centricity
-
Ingår i: Journal of Pharmaceutical Sciences. - 0022-3549.
-
Forskningsöversikt (refereegranskat)abstract
- This article evaluates the current gaps around the impact of post-manufacturing processes on the product qualities of protein-based biologics, with a focus on user centricity. It includes the evaluation of the regulatory guidance available, describes a collection of scientific literature and case studies to showcase the impact of post-manufacturing stresses on product and dosing solution quality. It also outlines the complexity of clinical handling and the need for communication, and alignment between drug providers, healthcare professionals, users, and patients. Regulatory agencies provide clear expectations for drug manufacturing processes, however, guidance supporting post-product manufacturing handling is less defined and often misaligned. This is problematic as the pharmaceutical products experience numerous stresses and processes which can potentially impact drug quality, safety and efficacy. This article aims to stimulate discussion amongst pharmaceutical developers, health care providers, device manufacturers, and public researchers to improve these processes. Patients and caregivers' awareness can be achieved by providing relevant educational material on pharmaceutical product handling.
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| 27. |
- Cheuk, Dominic, et al.
(författare)
-
Thermodynamics of the Enantiotropic Pharmaceutical Compound Benzocaine and Solubility in Pure Organic Solvents
- 2020
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 109:11, s. 3370-3377
-
Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic relationship between FI and FII of ethyl 4-aminobenzoate (benzocaine) has been investigated. Slurry conversion experiments show that the transition temperature below which FI is stable is located between 302 K-303 K (29 degrees C-30 degrees C). The polymorphs FI and FII have been characterised by infrared spectroscopy (IR), Raman spectroscopy, transmission powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC). The isobaric solid state heat capacities have been measured by DSC. The quantitative thermodynamic stability relationship has been determined in a comprehensive thermodynamic analysis of the calorimetric data. The solubility of both polymorphs has been determined in eight pure organic solvents over the temperature range 278 K-323 K by a gravimetric method. The mole fraction solubility of benzocaine decreases in the order: 1,4-dioxane, acetone, ethyl acetate, chloroform, acetonitrile, methanol, n-butanol and toluene. Comparison with the determined activity of solid benzocaine forms shows that negative deviation from Raoult's law ideality is found in dioxane, acetone and ethyl acetate solutions, and positive deviation in solutions of the other investigated solvents.
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| 28. |
- Cristofoletti, Rodrigo, et al.
(författare)
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Biowaiver monographs for immediate release solid oral dosage forms : efavirenz
- 2013
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 102:2, s. 318-329
-
Tidskriftsartikel (refereegranskat)abstract
- Literature data pertaining to the decision to allow a waiver of in vivo bioequivalence testing for the approval of immediate-release (IR) solid oral dosage forms containing efavirenz as the only active pharmaceutical ingredient (API) are reviewed. Because of lack of conclusive data about efavirenz's permeability and its failure to comply with the "high solubility" criteria according to the Biopharmaceutics Classification System (BCS), the API can be classified as BCS Class II/IV. In line with the solubility characteristics, the innovator product does not meet the dissolution criteria for a "rapidly dissolving product." Furthermore, product variations containing commonly used excipients or in the manufacturing process have been reported to impact the rate and extent of efavirenz absorption. Despite its wide therapeutic index, subtherapeutic levels of efavirenz can lead to treatment failure and also facilitate the emergence of efavirenz-resistant mutants. For all these reasons, a biowaiver for IR solid oral dosage forms containing efavirenz as the sole API is not scientifically justified for reformulated or multisource drug products.
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| 29. |
- Dahlgren, David, et al.
(författare)
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Direct In Vivo Human Intestinal Permeability (P-eff) Determined with Different Clinical Perfusion and Intubation Methods
- 2015
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 104:9, s. 2702-2726
-
Forskningsöversikt (refereegranskat)abstract
- Regional in vivo human intestinal effective permeability (P-eff) is calculated by measuring the disappearance rate of substances during intestinal perfusion. P-eff is the most relevant parameter in the prediction of rate and extent of drug absorption from all parts of the intestine. Today, human intestinal perfusions are not performed on a routine basis in drug development. Therefore, it would be beneficial to increase the accuracy of the in vitro and in silico tools used to evaluate the intestinal P-eff of novel drugs. This review compiles historical P-eff data from 273 individual measurements of 80 substances from 61 studies performed in all parts of the human intestinal tract. These substances include: drugs, monosaccharaides, amino acids, dipeptides, vitamins, steroids, bile acids, ions, fatty acids, and water. The review also discusses the determination and prediction of P-eff using in vitro and in silico methods such as quantitative structure-activity relationship, Caco-2, Ussing chamber, animal intestinal perfusion, and physiologically based pharmacokinetic (PBPK) modeling. Finally, we briefly outline how to acquire accurate human intestinal P-eff data by deconvolution of plasma concentration-time profiles following regional intestinal bolus dosing.
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| 30. |
- Damoiseaux, David, et al.
(författare)
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Population Pharmacokinetic Modelling to Support the Evaluation of Preclinical Pharmacokinetic Experiments with Lorlatinib
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:2, s. 495-504
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of transporters and enzymes on drug pharmacokinetics is increasingly evaluated using genetically modified animals that have these proteins either knocked-out or their human orthologues transgenically expressed. Analysis of pharmacokinetic data obtained in such experiments is typically performed using non-compartmental analysis (NCA), which has limitations such as not being able to identify the PK parameter that is affected by the genetic modification of the enzymes or transporters and the requirement of intense and homogeneous sampling of all subjects. Here we used a compartmental population pharmacokinetic modeling approach using PK data from a series of genetically modified mouse experiments with lorlatinib to extend the results and conclusions from previously reported NCA analyses. A compartmental population pharmacokinetic model was built and physiologically plausible covariates were evaluated for the different mouse strains. With the model, similar effects of the strains on the area under the concentration-time curve (AUC) from 0 to 8 hours were found as for the NCA. Additionally, the differences in AUC between the strains were explained by specific effects on clearance and bioavailability for the strain with human expressing CYP3A4. Finally, effects of multidrug efflux transporters ATP-binding cassette (ABC) sub-family B member 1 (ABCB1) and G member 2 (ABCG2) on brain efflux were quantified. Use of compartmental population PK modeling yielded additional insight into the role of drug-metabolizing enzymes and drug transporters in mouse experiments compared to the NCA. Furthermore, these models allowed analysis of heterogeneous pooled datasets and the sparse organ concentration data in contrast to classical NCA analyses.
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| 31. |
- Dening, Tahnee J., et al.
(författare)
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Improving Correlations Between Drug Solubilization and In Vitro Lipolysis by Monitoring the Phase Partitioning of Lipolytic Species for Lipid-Based Formulations
- 2019
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 1520-6017 .- 0022-3549. ; 108:1, s. 295-304
-
Tidskriftsartikel (refereegranskat)abstract
- Solution proton nuclear magnetic resonance analysis was used in conjunction with in vitro lipolysis to elucidate the time-dependent speciation and release of lipolytic products during the digestion of lipid-loaded inorganic particles, allowing correlations to be made between the phase partitioning of lipolytic products and an encapsulated poorly soluble drug. Silicon dioxide, montmorillonite, and laponite were used to encapsulate medium chain triglycerides into solid-state lipid-based formulations (LBFs), and coumarin 102 was selected as a model poorly soluble compound. The specific inorganic carrier material used to encapsulate medium chain triglycerides significantly impacted the release and partitioning of the solubilizing lipolytic products, that is, diglycerides, monoglycerides, and fatty acids. A strong linear correlation was obtained between drug solubilization and fatty acid release to the aqueous phase (R2 = 0.996), indicating fatty acids to be the most important lipid species for enabling solubilization and potential drug absorption in vivo. This method was developed to improve upon the use of pH-stat titration for characterizing LBF digestion during in vitro lipolysis studies and is demonstrated herein to provide useful insights into how the selected inorganic carrier material impacts LBF performance when solid-state LBF powders are fabricated via adsorption.
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| 32. |
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| 33. |
- Ehrhardt, Carsten, et al.
(författare)
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Current Progress Toward a Better Understanding of Drug Disposition Within the Lungs : Summary Proceedings of the First Workshop on Drug Transporters in the Lungs
- 2017
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 106:9, s. 2234-2244
-
Tidskriftsartikel (refereegranskat)abstract
- The School of Pharmacy and Pharmaceutical Sciences at Trinity College Dublin hosted the "1st Workshop on Drug Transporters in the Lungs" in September 2016 to discuss the impact of transporters on pulmonary drug disposition and their roles as drug targets in lung disease. The workshop brought together about 30 scientists from academia and pharmaceutical industry from Europe and Japan and addressed the primary questions: What do we know today, and what do we need to know tomorrow about transporters in the lung? The 3 themes of the workshop were: (1) techniques to study drug transporter expression and actions in the lungs; (2) drug transporter effects on pulmonary pharmacokinetics-case studies; and (3) transporters as drug targets in lung disease. Some of the conclusions of the workshop were: suitable experimental models that allow studies of transporter effects are available; data from these models convincingly show a contribution of both uptake and efflux transporters on pulmonary drug disposition; the effects of transporters on drug lung PK is now better conceptualized; some transporters are associated with lung diseases. However, more work is needed to establish which of the available models best translate to the clinical situation.
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| 34. |
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| 35. |
- Elfstrand, Lidia, et al.
(författare)
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The effect of starch material, encapsulated protein and production conditions on the protein release from starch microspheres.
- 2009
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549. ; 98, s. 3802-3815
-
Tidskriftsartikel (refereegranskat)abstract
- The present study describes the preparation of 11 batches of starch microspheres for drug delivery. Parameters such as the type of starch material, the type of protein, and the incubation time of the process were varied, and the obtained microspheres differed in yield, encapsulation efficiency and physical properties. The crystalline/ordered structure (obtained through X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC)), the microscopic appearance and the surface morphology (viewed with scanning electron microscopy (SEM)) were found to differ between the batches depending on the starch type, encapsulated protein and incubation conditions that were employed. Freeze-drying was found to have a destructive effect on the ordered structure of the starch and this effect varied with regard to preparation conditions. Drug release experiments demonstrated that the release from the starch matrix depended on the type of protein as well as on the incubation time during the manufacturing at temperatures of 6 degrees C and 37 degrees C. The enzymatic degradation of starch was slightly different between the materials depending on the crystalline/ordered structure that had formed during the preparation. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci.
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| 36. |
- Elversson, Jessica, et al.
(författare)
-
An atomic force microscopy approach for assessment of particle density applied to single spray-dried carbohydrate particles
- 2007
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 96:4, s. 905-912
-
Tidskriftsartikel (refereegranskat)abstract
- To evaluate an atomic force microscopy (A-FM) approach for effective density analysis of single spray dried carbohydrate particles in order to investigate the internal structure of the particles. In addition, the AFM method was compared to an established technique, that is gas pycnometry. Resonant frequency AFM analysis was employed for determination of the mass of individual particles of spray-dried lactose, mannitol, and a mixture of sucrose/dextran (4:1). The effective particle density was calculated using the diameter of the spherical particles obtained from light microscopy. The apparent particle density was further analyzed with gas pycnometry. It was observed by microscopy that particles appeared either ""solid"" or ""hollow."" A solid appearance applied to an effective particle density close to the true density of the material, whereas a density around 1 g/cm(3) corresponded to a hollow appearance. However, carbohydrates, which crystallized during spray drying, for example, mannitol appeared solid but the 3 average effective particle density was 0.95 g/cm, indicating a continuous but porous structure. AFM measurements of effective particle density corroborate the suggestion of differences in particle structure caused by the varying propensity of carbohydrates to crystallize during spray drying, resulting in mainly either amorphous hollow or crystalline porous particles.
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| 37. |
- Elversson, J, et al.
(författare)
-
Droplet and particle size relationship and shell thickness of inhalable lactose particles during spray drying
- 2003
-
Ingår i: Journal of Pharmaceutical Sciences. - : Wiley. - 0022-3549 .- 1520-6017. ; 92, s. 900-910
-
Tidskriftsartikel (refereegranskat)abstract
- To find means of controlling the size and density of particles intended for inhalation the relationship between droplet and particle size during spray drying was investigated. Lactose solutions were atomized with a two-fluid nozzle and dried in a laboratory spray drier. The effects of nozzle orifice diameter, atomization airflow and feed concentration on droplet and particle size were examined. Mass median diameter of both droplets and particles were analyzed with laser diffraction. In addition, scanning electron microscopy and transmission electron microscopy were used for studies of particle shape and morphology. It was demonstrated that nozzle orifice diameter and airflow, but not feed concentration controlled the droplet size during atomization. Increasing droplet size increased particle size but the effect was also influenced by feed concentration. Particles from solutions of a low concentration (1% w/w) were smaller than those from higher concentrations (5-20% w/w). This may be partly explained by lower yields at higher feed concentrations, but may also be related to differences in drying rate. Spray-dried lactose solutions formed hollow particles, and it was suggested that the shell thickness of the particles increased with increasing feed concentration
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| 38. |
- Elversson, Jessica, et al.
(författare)
-
Particle size and density in spray drying : effects of carbohydrate properties
- 2005
-
Ingår i: Journal of Pharmaceutical Sciences. - : Wiley. - 0022-3549 .- 1520-6017. ; 94:9, s. 2049-2060
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine some fundamental aspects of the particle formation during spray drying, related to particle size and density. Particles were prepared in a laboratory spray dryer from carbohydrates with different solubility and crystallization propensity, such as lactose, mannitol, and sucrose/dextran 4:1. The feed concentrations ranged from 1% w/w to saturated and the size of droplets and particles were measured by laser diffraction. Particles were also characterized by various microscopy techniques (i.e., scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and light microscopy), differential scanning calorimetry (DSC), gas adsorption, and gas pycnometry. As demonstrated larger particles could be obtained by either increasing the droplet size during atomization; increasing the concentration of the feed solution; or decreasing the solubility of the solute. The apparent particle density, measured by gas pycnometry, was found negatively correlated to the feed concentration. Due to the nonlinear relationship between the feed concentration and the particle size, it was concluded that higher solids load would cause an increase in the effective particle density and that the reduction in the apparent particle density was a result of a gradually less permeable particle surface. Further, the crystallization propensity of the carbohydrate influenced the particle formation and resulted in either hollow or porous particles.
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| 39. |
- Elversson, J, et al.
(författare)
-
Particle size and density in spray drying - effects of carbohydrate properties
- 2005
-
Ingår i: Journal of Pharmaceutical Sciences. - 0022-3549 .- 1520-6017. ; 94, s. 2049-2060
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine some fundamental aspects of the particle formation during spray drying, related to particle size and density. Particles were prepared in a laboratory spray dryer from carbohydrates with different solubility and crystallization propensity, such as lactose, mannitol and sucrose/dextran 4:1. The feed concentrations ranged from 1% w/w to saturated and the size of droplets and particles were measured by laser diffraction. Particles were also characterized by various microscopy techniques (i.e. scanning electron microscopy, confocal laser scanning microscopy and light microscopy), differential scanning calorimetry, gas adsorption, and gas pycnometry. As demonstrated larger particles could be obtained by either increasing the droplet size during atomization; increasing the concentration of the feed solution; or decreasing the solubility of the solute. The apparent particle density was found negatively correlated to the feed concentration. Due to the non-linear relationship between the feed concentration and the particle size, it was concluded that higher solids load may cause an increase in the effective particle density and that the reduction in the apparent particle density was a result of a gradually less permeable particle surface. Further, the crystallization propensity of the carbohydrate influenced the particle formation and resulted in either hollow or porous particles
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| 40. |
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| 41. |
- Eriksen, Jonas Borregaard, et al.
(författare)
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'Stirred not Shaken!' Comparing Agitation Methods for Permeability Studies Using a Novel Type of 96-Well Sandwich-Plates
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:1, s. 32-40
-
Tidskriftsartikel (refereegranskat)abstract
- In order to achieve a high sample throughput, permeation experiments are often carried out using 96-well sandwich plates. Even though agitation is regarded as important, permeation studies in 96-well format are often carried out without agitation since orbital shaking, the most common agitation method for 96-well plates, has been reported to create difficulties (e.g., well-to-well cross-talk), and high cost and low availability limits the use of other agitation techniques (e.g., magnetic stirring). This study investigates how orbital shaking and magnetic stirring affect the apparent permeability of model compounds with different water-solubilities (methylene blue, carbamazepine, and albendazole) using a novel 96-well sandwich plate comprising a cellulose-hydrate membrane (PermeaPlain (R) plate). Orbital shaking was found less efficient than magnetic stirring in terms of homogeneously distributing a small volume of dye within the donor compartment. Furthermore, in terms of achieving maximum trans-barrier flux, magnetic stirring was found a more effective agitation method than orbital shaking. Obviously, with orbital shaking the medium in the bottom compartment of the sandwich plates never was mixed in-phase. The impact of insufficient mixing on permeation was found strongest with the most lipophilic compound, which correlates with literature reports that the contribution of the unstirred water layer towards the overall resistance of the barrier is most expressed in case of lipophilic drugs. Finally, it was tested how different liquid volumes in the bottom compartment of the plates affect the well-to-well cross-talk during permeation experiments under orbital shaking. This study revealed that 250-300 mu L should be used in the bottom compartment of the sandwich plates to reduce well-to-well cross-talk when using orbital shaking for agitation. (C) 2021 Published by Elsevier Inc. on behalf of American Pharmacists Association.
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| 42. |
- Eriksson Barman, Sandra, 1985, et al.
(författare)
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New characterization measures of pore shape and connectivity applied to coatings used for controlled drug release
- 2021
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 1520-6017 .- 0022-3549. ; 110:7, s. 2753-2764
-
Tidskriftsartikel (refereegranskat)abstract
- Pore geometry characterization-methods are important tools for understanding how pore structure influences properties such as transport through a porous material. Bottlenecks can have a large influence on transport and related properties. However, existing methods only catch certain types of bottleneck effects caused by variations in pore size. We here introduce a new measure, geodesic channel strength, which captures a different type of bottleneck effect caused by many paths coinciding in the same pore. We further develop new variants of pore size measures and propose a new way of visualizing 3-D characterization results using layered images. The new measures together with existing measures were used to characterize and visualize properties of 3-D FIB-SEM images of three leached ethyl-cellulose/hydroxypropyl-cellulose films. All films were shown to be anisotropic, and the strongest anisotropy was found in the film with lowest porosity. This film had very tortuous paths and strong geodesic channel-bottlenecks, while the paths through the other two films were relatively straight with well-connected pore networks. The geodesic channel strength was shown to give important new visual and quantitative insights about connectivity, and the new pore size measures provided useful information about anisotropies and inhomogeneities in the pore structures. The methods have been implemented in the freely available software MIST.
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| 43. |
- Fagerholm, Urban, et al.
(författare)
-
In Silico Predictions of the Gastrointestinal Uptake of Macrocycles in Man Using Conformal Prediction Methodology
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:9, s. 2614-2619
-
Tidskriftsartikel (refereegranskat)abstract
- The gastrointestinal uptake of macrocyclic compounds is not fully understood. Here we applied our previously validated integrated system based on machine learning and conformal prediction to predict the passive fraction absorbed (f(a)), maximum fraction dissolved (f(diss)), substrate specificities for major efflux transporters and total fraction absorbed (f(a,tot)) for a selected set of designed macrocyclic compounds (n = 37; MW 407-889 g/mol) and macrocyclic drugs (n = 16; MW 734-1203 g/mole) in vivo in man. Major aims were to increase the understanding of oral absorption of macrocycles and further validate our methodology. We predicted designed macrocycles to have high f(a )and low to high f(diss) and f(a,tot, )and average estimates were higher than for the larger macrocyclic drugs. With few exceptions, compounds were predicted to be effluxed and well absorbed. A 2-fold median prediction error for f(a,tot )was achieved for macrocycles (validation set). Advantages with our methodology include that it enables predictions for macrocycles with low permeability, Caco-2 recovery and solubility (BCS IV), and provides prediction intervals and guides optimization of absorption. The understanding of oral absorption of macrocycles was increased and the methodology was validated for prediction of the uptake of macrocycles in man.(C) 2022 American Pharmacists Association. Published by Elsevier Inc. All rights reserved.
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| 44. |
- Fagerholm, Urban, et al.
(författare)
-
The Impact of Reference Data Selection for the Prediction Accuracy of Intrinsic Hepatic Metabolic Clearance
- 2022
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:9, s. 2645-2649
-
Tidskriftsartikel (refereegranskat)abstract
- In vitro-in vivo prediction results for hepatic metabolic clearance (CLH) and intrinsic CLH (CLint) vary widely among studies. Reasons are not fully investigated and understood. The possibility to select favorable reference data for in vivo CLH and CLint and unbound fraction in plasma (f(u)) is among possible explanations. The main objective was to investigate how reference data selection influences log in vitro and in vivo CLint-correlations (r(2)). Another aim was to make a head-to-head comparison vs an in silico prediction method. Human hepatocyte CLint-data for 15 compounds from two studies were selected. These were correlated to in vivo CLint estimated using different reported CLH- and f(u)-estimates. Depending on the choice of reference data, r(2) from two studies were 0.07 to 0.86 and 0.06 to 0.79. When using average reference estimates a r(2) of 0.62 was achieved. Inclusion of two outliers in one of the studies resulted in a r(2) of 0.38, which was lower than the predictive accuracy (q(2)) for the in silico method (0.48). In conclusion, the selection of reference data appears to play a major role for demonstrated predictions and the in silico method showed higher accuracy and wider range than hepatocytes for human in vivo CLint-predictions. (C) 2022 Published by Elsevier Inc. on behalf of American Pharmacists Association.
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| 45. |
- Falk, Yana Znamenskaya, et al.
(författare)
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Interactions of Perfluorohexyloctane With Polyethylene and Polypropylene Pharmaceutical Packaging Materials.
- 2020
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 109:7, s. 2180-2188
-
Tidskriftsartikel (refereegranskat)abstract
- Semifluorinated alkanes (SFAs) are aprotic solvents, which may be used as drug solvents for topical ocular applications, for instance, in dry eye syndrome. Their physical properties suggest that they might be prone to interaction with plastic materials, such as, polyethylene (PE) and polypropylene (PP), which are commonly used as packaging materials for pharmaceutical products. In this study, we investigate interactions of PE and PP with a liquid SFA perfluorohexyloctane (PFHO) using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross-polarized light microscopy. Binary phase diagrams of PFHO-PE and PFHO-PP systems demonstrating interactions of PFHO with the polymeric materials were constructed based on DSC data. According to this data, PFHO tends to lower the melting temperatures of PE and PP. The equilibrium values of solubilities of the polymers in PFHO and PFHO in the polymers were obtained by extrapolation of melting enthalpy data. Absorption of PFHO by PE and PP materials at ambient conditions after four weeks of equilibration was also studied by TGA. From the presented results, it may be concluded that thorough studies of interactions of PE or PP with SFAs are required when these materials are used as packaging components in SFA-based formulations.
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| 46. |
- Forsgren, Johan, et al.
(författare)
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A ceramic drug delivery vehicle for oral administration of highly potent opioids.
- 2010
-
Ingår i: Journal of pharmaceutical sciences. - : Elsevier BV. - 1520-6017 .- 0022-3549. ; 99:1, s. 219-26
-
Tidskriftsartikel (refereegranskat)abstract
- Pellets composed of the ceramic material Halloysite and microcrystalline cellulose were synthesized with the aim of producing a drug delivery vehicle for sustained release of the opioid Fentanyl with low risk for dose dumping at oral intake of the highly potent drug. Drug release profiles of intact and crushed pellets, to simulate swallowing without or with chewing, in pH 6.8, pH 1, and in 48% ethanol were recorded in order to replicate the conditions in the small intestines, in the stomach, as well as cointake of the drug with alcohol. The drug release was analyzed by employing the Weibull equation, which showed that the release profiles were either governed by fickian diffusion (intact pellets in pH 6.8 and in ethanol) or by diffusion in a fractal or disordered pore network (intact pellets in pH 1 and crushed pellets in all solutions). A sustained release for approximately 3-4 h was obtained in all studied solutions from intact pellets, whereas crushed pellets released the drug content during approximately 2-3 h. The finding that a sustained release profile could be obtained both in alcohol and after crushing of the pellets, shows that the ceramic carrier under investigation, at least to some extent, hampers dose dumping, and may thus be a promising material in future developments of new opioid containing oral dosage forms.
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| 47. |
- Fransén, Nelly, et al.
(författare)
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Changes in the mucoadhesion of powder formulations after drug application investigated with a simplified method
- 2008
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 97:9, s. 3855-3864
-
Tidskriftsartikel (refereegranskat)abstract
- The residence time in the nasal cavity can be prolonged by dry particles that absorb water and subsequently increase the viscosity of the mucus layer. A novel nasal drug delivery system based on interactive mixtures has previously been developed, where fine particles of the active component are adhered to the surface of mucoadhesive carrier particles by dry mixing. The surface coverage may alter the original mucoadhesiveness of the carrier particles and to investigate this, a simplified tensile strength method was developed and evaluated. Reliable results were obtained with a plastic coated absorbent paper covered by a mucin solution as a substitution for porcine nasal mucosa and should also be applicable to other dry particle systems. The method showed that the swelling of sodium starch glycolate particles was slightly delayed, corresponding to the degree of hydrophobic surface coverage. Carrier particles of partly pregelatinized maize starch were not influenced by the addition of a hydrophobic substance, probably because of the rough particle shape that inhibited a complete surface coverage. It was concluded that the surface coverage of carrier particles in interactive mixtures only could cause a short delay in water absorption that should not affect their mucoadhesive characteristics in vivo.
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| 48. |
- Frenning, Göran, et al.
(författare)
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A new method for characterizing the release of drugs from tablets in low liquid surroundings
- 2002
-
Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 91:3, s. 776-784
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this article is to introduce a method capable of determining early drug dissolution in small amounts of liquid. The method is based on the measurement of the alternating ionic current through a cell containing the dissolution medium and the substance to be dissolved. Both the initial and more prolonged absorption of liquid into tablets can also be determined by using the same technique. The method has been tested on two tablet formulations containing agglomerated micronized cellulose and NaCl as a model drug. Release of NaCl was delayed from both formulations; the extent of the delay was strongly formulation-dependent only when the surrounding liquid was in short supply. This finding shows that new drug dissolution phenomena may be encountered in small liquid volumes; these phenomena would not have been seen with the large volume methods normally used in in vitro dissolution tests. Hence, for formulations intended for sublingual, buccal, or rectal administration, i.e., in areas where liquid is scarce, in vitro dissolution tests should be performed in small volumes of dissolution medium.
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| 49. |
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| 50. |
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