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- Elfstrand, Lidia, et al.
(författare)
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From starch to starch microspheres: Factors controlling the microspheres quality
- 2006
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Ingår i: Stärke. - : Wiley. - 0038-9056. ; 58:8, s. 381-390
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Tidskriftsartikel (refereegranskat)abstract
- Starch microparticle is a dosage form suitable for encapsulation of protein drugs. The microparticle characteristics can be influential factors for consecutive sustained drug release from the starch matrix and impact its ability to be coated by poly(D,L-lactide-co-glycolide). In this study, six types of starch microparticles were investigated and characterized. Desired qualities of the microspheres such as spherical form of the particles, well-defined and sharp particle contours were coincident with coarse surface morphology, sharp and distinct peaks in DSC and X-ray graphs. It was concluded that the quality of the starch microparticles was influenced by molecular properties of the starch material as well as type of buffer, and these factors were related to recrystallization kinetics, amount and quality of ordered/crystalline structure of final starch microspheres and their microscopic appearance.
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| 2. |
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| 3. |
- Fredenberg, Susanne, et al.
(författare)
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Development of mass transport resistance in poly(lactide-co-glycolide) films and particles - A mechanistic study.
- 2011
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 1873-3476 .- 0378-5173. ; 409:1-2, s. 194-202
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Tidskriftsartikel (refereegranskat)abstract
- Poly(d,l-lactide-co-glycolide) (PLG) is the most frequently used biodegradable polymer in the controlled release of an encapsulated drug. The purpose of this work was to explain the surprisingly slow diffusion through this polymer, and locate the major source of mass transport resistance. Diffusion of human growth hormone (hGH) and glucose through PLG films was undetectable (using a diffusion cell), although the degraded polymer contained several times more water than polymer mass. In vitro release of hGH from PLG-coated particles also showed a surprisingly slow rate of release. Non-porous regions inside the PLG films were detected after three weeks of degradation using dextran-coupled fluorescent probes and confocal microscopy. The findings were supported by scanning electron microscopy. Diffusion through PLG films degraded for five weeks was significantly increased when the porosity of both surfaces was increased due to the presence of ZnCl(2) in the buffer the last 3 days of the degradation period. The results indicated high mass transport resistance inside the films after three weeks of degradation, and at the surfaces after five weeks of degradation. These results should also be applicable to microparticles of different sizes. Knowledge of the reason for transport resistance is important in the development of pharmaceuticals and when modifying the rate of drug release.
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