| 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
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 110:1, s. 42-49
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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. |
- 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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| 8. |
- Asad, Shno, et al.
(författare)
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Proteomics-Informed Identification of Luminal Targets For In Situ Diagnosis of Inflammatory Bowel Disease
- 2021
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 110:1, s. 239-250
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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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| 9. |
- 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
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:3, s. 852-858
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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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| 10. |
- 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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