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Drug distribution and redistribution rates in phases of dispersed self micro-emulsifying drug delivery systems
Başlık:
Drug distribution and redistribution rates in phases of dispersed self micro-emulsifying drug delivery systems
Yazar:
Shah, Siddharth K., author.
ISBN:
9780438075801
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (160 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Robert A. Bellantone.
Özet:
To overcome poor solubility of a drug, there are several approaches considered to overcome the problem. Among lipid-based drug delivery approach, self- M icroemulsifying Drug Delivery Systems (SMEDDS) has been employed more often lately. Self-microemulsifying Drug Delivery Systems (SMEDDS) are isotropic mixtures of oil, surfactant and/or cosurfactants, and a drug that spontaneously forms an oil-inwater microemulsion upon gentle agitation with water. When dispersed in the gastrointestinal (GI) tract, the motility of stomach provides necessary agitation for emulsification. SMEDDS incorporated with a poorly water-soluble drug demonstrates improved drug absorption since it maintains the drug in a solubilized state in the GIT tract.
By determining the free drug concentration by pulsatile microdialysis(PMD) method and using mass balance equation. drug distribution in different phases of the microemulsion was determined. The amount of oil, pH, and temperature displayed important effects on drug distribution after in vitro which can help predict in vivo performance. However, these are static or equilibrium measurements. In reality, the changing environment can affect the thermodynamics of the systems, including the drug solubility and distribution properties. Sudden changes in the environment can induce diffusional and redistribution processes, and rapidly change the drug delivery characteristics of the microemulsion(ME) formulations after administration.
Thus. the dynamic PMD technique used to determine free drug concentration in rapidly changing systems was calibrated for the system that rapidly changes in a known manner and then employed to estimate rapid drug redistribution into and/or out of the microemulsion globules the induced by a sudden change in pH. Such redistribution rates have never been measured, and perhaps only with PMD technique it has become possible as it allows to measure the change in concentration with rapid sampling as quick as 10 seconds or lower., but the time of redistribution has never been measured. Similarly, the release of drug as a function of time to the free dissolved form in the aqueous phase that occurs during self-emulsification has never been evaluated as a function of time which was made possible by employing PMD technique.
Notlar:
School code: 0198
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
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