| 1. |
- Adane, M., et al.
(författare)
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The use of extragranular disintegrants in multiple-unit tablet formulations : effect on compressibility, compactibility and disintegration
- 2007
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Ingår i: Journal of drug delivery science and technology. - 1773-2247. ; 17:4, s. 279-284
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Tidskriftsartikel (refereegranskat)abstract
- Multiple-unit tablets formed from mixtures of microcrystalline cellulose pellets and disintegrants (Ac-Di-Sol, Primojel or Kollidon CL) by compaction were investigated with the aim of controlling tablet tensile strength and disintegration time. The effects of pellet porosity, compaction pressure, and type and amount of disintegrant were studied. Primojel made the pellets less prone to deformation during compression, while the other two disintegrants had very minor effects on the compression behavior. Ac-Di-Sol and Primojel generally increased the tablet tensile strength, whereas the effect of Kollidon CL was dependent on the initial pellet porosity. Kollidon CL was found to significantly reduce the disintegration time, but the other two disintegrants had variable efficacy, and for the low-porosity pellets significantly increased the disintegration time. These results are interpreted as resulting from the interplay between the mechanical characteristics of the pellets and the mechanisms of action of the disintegrants.
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| 2. |
- Ahnfelt, Emelie, et al.
(författare)
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Lipiodol-based emulsions used for transarterial chemoembolization and drug delivery : Effects of composition on stability and product quality
- 2019
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Ingår i: Journal of Drug Delivery Science and Technology. - : ELSEVIER. - 1773-2247. ; 53
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Tidskriftsartikel (refereegranskat)abstract
- Transarterial chemoembolization with emulsion-based formulations using doxorubicin hydrochloride (DOX) and Lipiodol (R) is the golden standard for the loco-regional treatment of unresectable hepatocellular carcinoma (HCC). However, from a pharmaceutical quality perspective these emulsions are poorly characterized. In this study, clinically relevant Lipiodol (R)-based emulsions were characterized in terms of emulsion stability, continuous phase classification and droplet-size distribution. Also, the solubility of DOX in the different emulsion components and the distribution of DOX to the lipid phase were investigated. These are key features to investigate due to the claimed tumor-seeking properties of Lipiodol (R). The in vitro release of DOX was studied in a miniaturized dialysis method and an empirical release model was applied to adjust for the passage of DOX across the dialysis membrane. The most stable emulsion ( > 72 h) was classified as water-in-oil (w/o), had the highest distribution of DOX to the lipid phase (20%) and an aqueous-to-lipid phase ratio of 1:4. The composition of the aqueous phase was a mixture (v/v) of iohexol (85%) and water (15%). Emulsions containing iohexol and a high aqueousto-lipid phase ratio (1:2-1:4) displayed prolonged in vitro release profiles of DOX. This study further emphasizes the medical need to standardize these emulsion-based drug delivery systems.
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| 3. |
- Ahrenstedt, Lage, et al.
(författare)
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Sustained zero-order release of dexamethasone after incorporation into crosslinked PEG-dendrons using click reactions
- 2024
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Ingår i: Journal of Drug Delivery Science and Technology. - : Elsevier BV. - 1773-2247. ; 95
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogel-based localised drug delivery minimises systemic side effects and a linear release profile ensuring a sustained drug release over time, crucial for long-term therapy. The current paper describes the use of the Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAc) to append azidified Dexamethasone (Dex) onto dendrons of first- and second-generation PEGs. Crosslinking with thiolated PEGs using either thiol-acrylate or nucleophilic addition reactions yielded gels containing β-thio-ether ester groups that imparted enhanced hydrolytic susceptibility. In vitro gel degradation was followed gravimetrically and expressed as swelling ratios. Thiol-acrylate crosslinked hydrogels exhibited zero-order Dex release kinetics over 11, 27, and 16 days (G1, G1-star, and G2). Crosslinking the G1-gels by nucleophilic addition also resulted in linear release and the end point was reached in 5 days. Hydrolysis was accounted as the main release mechanism for covalently bound Dex, while physically incorporated Dex showed undefined rapid burst or first-order release, with most of the drug released in the initial 1–3 days. Eluates from covalently bound Dex maintained high activity, whereas Trap-Dex gels lost activity over time, as detected by the upregulation of luciferase expression from a transformed cell line. This novel chemistry combination offers precise drug release control applicable beyond Dex to drugs with suitable nucleophilic groups.
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| 4. |
- AlHayali, Amani, et al.
(författare)
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Silodosin oral films : Development, physico-mechanical properties and in vitro dissolution studies in simulated saliva
- 2019
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Ingår i: Journal of Drug Delivery Science and Technology. - : Elsevier. - 1773-2247. ; 53
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Tidskriftsartikel (refereegranskat)abstract
- Sublingual film dosage forms for drugs used for fast symptomatic treatment have promise because they allow a rapid onset of action. The aim of this study was to prepare films of silodosin intended for sublingual administration for the symptomatic treatment of benign prostatic hyperplasia in men. Hydroxypropyl methylcellulose (HPMC) or hydroxypropyl methylcellulose acetate succinate (HPMC-AS) were used as film-forming polymers. The effects of the polymers and the surfactant tocopherol polyethylene glycol succinate (TPGS) on the physico-mechanical properties and dissolution behavior of the films in simulated saliva were investigated. The eight silodosin oral films developed (F1–F8) contained 8 mg silodosin per 6 cm2 film and HPMC or HPMC-AS in drug:polymer ratios of 1:5 or 1:3, while four also contained TPGS (0.5% w/w). The films were characterized using DSC, TGA, SEM, and PXRD and the mechanical properties were investigated by measuring tensile strength, elongation at break and Young's modulus. The mechanical properties of the films were dependent on the ratio of polymer used. The in vitro dissolution and drug release studies indicated that HPMC-AS films disintegrated more quickly than HPMC films. Silodosin was shown to be dispersed within the polymers. Despite silodosin being submicronized in the HPMC films, the dissolution and drug release rate (time for 80% release) from HPMC films was significantly faster than from HPMC-AS films. TPGS increased the drug release rate to a greater extent with HPMC than with HPMC-AS. The degree of saturation of formulation F4 was >1, which shows potential for improving oral absorption of silodosin.
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| 5. |
- Ali, Abdullah, 1985-, et al.
(författare)
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Will a water gradient in oral mucosa affect transbuccal drug absorption?
- 2018
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Ingår i: Journal of Drug Delivery Science and Technology. - : Elsevier. - 1773-2247. ; 48, s. 338-345
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Tidskriftsartikel (refereegranskat)abstract
- Formulations for buccal drug delivery often comprise polymers to facilitate mucoadhesion based on water sorption. The main objective of the current study was therefore to evaluate the effect of dehydration on drug uptake through oral mucosa. We have used diffusion cells with excised porcine mucosa to study uptake of three alternative drugs (i.e., Metronidazole, Benzydamine and Xylometazoline) together with polyethylene glycol (PEG) as the model polymer for adjusting water activity in the test solutions. Taking drug activity into account, we can conclude that addition of PEG results in a drug flux through mucosa that is about two times lower for Metronidazole and more than 40 times lower for Xylometazoline compared to that from a pure PBS-solution. However, for Benzydamine the uptake through mucosa was more or less the same, which could possibly be due to the high PEG-concentration (65 wt%) affecting the dissociation constant and thus the permeability. These results indicate that an increased water gradient may have the same limiting effect on permeability through oral mucosa as previously seen for skin. Thus, water gradient effects should be a factor to consider when developing buccal adhesive formulations.
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| 6. |
- Bakardzhiev, Pavel, et al.
(författare)
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Novel polyglycidol-lipid conjugates create a stabilizing hydrogen-bonded layer around cholesterol-containing dipalmitoyl phosphatidylcholine liposomes
- 2015
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Ingår i: Journal of Drug Delivery Science and Technology. - : Elsevier. - 1773-2247. ; 29, s. 90-98
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid liposomes resulting from co-assembly of dipalmitoylphosphatidylcholine and polyglycidol-derivatized lipids were prepared. The latter were composed of a lipid-mimetic residue to which a linear polyglycidol chain (degree of polymerization, DP, in the 23–110 range) was conjugated. Formulations with varying copolymer type and content were prepared by film hydration technique followed by extrusion. The hybrid structures were studied by means of dynamic and electrophoretic light scattering, cryogenic transmission electron microscopy, and fluorescence spectroscopy. Cytotoxicity towards OPM-2 (multiple myeloma) and EJ (human urinary bladder carcinoma) cell lines was assessed as well. Predominantly unilamellar liposomes with mean hydrodynamic diameters in the 113–134 nm range and neutral to slightly negative surface potential were prepared. The integrity of liposomes containing copolymers with DP of the polyglycidol chain 23 and 30 was preserved at copolymer contents up to 10 mol%. Bilayer disks were observed at somewhat lower contents of the copolymers of the highest DP of the polyglycidol chain. The hybrid structures were less leaky than the plain liposomes, which was attributed to formation of a strongly hydrogen-bonded polyglycidol layer around the bilayer membrane. They exhibited low toxicological potential, favorable physicochemical characteristics, and ability to act as containers for sustained release.
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| 7. |
- Bramer, Tobias, et al.
(författare)
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Effects of pH and ionic strength on catanionic drug-surfactant mixtures used for prolonged release from gels.
- 2007
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Ingår i: Journal of drug delivery science and technology. - 1773-2247. ; 17:4, s. 285-291
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the influence of pH and ionic strength on the phase behavior of two different catanionic drug-surfactant mixtures, and to study drug release from gels facilitated by the catanionic aggregates. Simplified phase diagrams were constructed for diphenhydramine or tetracaine mixed with SDS, varying the pH approximately between 6 and 11, and the NaCI concentration from 0.45 to 1.8%. The phases formed were studied visually, rheologically and with cryo-TEM. Some mixtures containing catanionic vesicles and micelles were selected for drug release studies from gels, varying the pH and NaCI concentration here as well. Both catanionic systems investigated proved relatively resilient to changes in the ionic strength. Changes in pH, on the other hand, caused marked effects to the phase behavior in both systems. The influence of pH was particularly strong in the drug-rich part of the tetracaine/SDS system, where increasing the pH causes precipitation. As expected, the drug release in both systems was somewhat affected by changes in both pH and ionic strength, but remained in all cases significantly prolonged as compared to the release of free, non-complexed, drug. These studies show that catanionic mixtures may be used to obtain prolonged drug release from gels, and that the concept also works when the gels are exposed to a pH that is a couple of units above the pKa of the cationic component. Furthermore, the ionic strength has no pronounced effect on the drug release, as long as it is kept within reasonable pharmaceutical levels.
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| 8. |
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| 9. |
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| 10. |
- Fichtner, Frauke, et al.
(författare)
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Drug release from compacted single inert matrix agglomerates
- 2007
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Ingår i: Journal of Drug Delivery Science and Technology. - 1773-2247. ; 17:4, s. 273-277
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Tidskriftsartikel (refereegranskat)abstract
- The effect of compaction on the drug release from single, sodium chloride loaded, microcrystalline cellulose agglomerates of different porosities was investigated in this study. The drug release from uncompacted agglomerates and from agglomerates regained from tablets compacted at a range of different compaction pressures was monitored measuring the conductivity of the dissolution medium in a recirculation flow-through system. The drug release profiles were described using the mean dissolution time (MDT), the variation of dissolution time (VDT) and the relative dispersion coefficient (RD). It was found that depending on physical structure changes of the matrix, the drug release rate of compacted agglomerates could be enhanced or retarded in comparison with uncompacted agglomerates. The retardation is suggested to be due to a densification of the matrix and the enhancement due to a crack formation in the external surface of the matrix.
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