Open AccessJournal Article
Release of medroxyprogesterone acetate from a silicone polymer.
T. J. Roseman,William I. Higuchi +1 more
TLDR
In this paper, the physicochemical factors involved in the in vitro release of medroxyprogesterone acetate (MPA) a water-insoluble steroid embedded in a silicone rubber matrix was based upon a model system which considered the matric boundary diffusion layer.Abstract:
A study of the physicochemical factors involved in the in vitro release of medroxyprogesterone acetate (MPA) a water-insoluble steroid embedded in a silicone rubber matrix was based upon a model system which considered the matric boundary diffusion layer; extensive mathematical equations for the model are presented for planar and cylindrical cases. Initial and long-time release rates were obtained. Zones of MPA depletion were measured microscopically as a function of time and the partition coefficient of MPA was determined. Following relatively constant initial release rates a nonlinear dependence of release rates upon MPA concentration (3% 12% 24%) was found. As MPA diffused from the matrix well-defined zones of depletion developed and were photographed. Comparison of the present model to the T. Higuchi model of drug release (based on a purely matrix-controlled system) indicated that when boundary layer was considered a better fit of experimental data to theory was found. Findings suggest that the partition coefficient diffusion coefficients medroxyprogesterone acetate concentration within the polymer and agitation conditions play important roles in the release process. The applicability of the model to an in vivo system (in which slower release of MPA has been observed) is evaluated.read more
Citations
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Modeling of diffusion controlled drug delivery.
TL;DR: The aim of this article is to give an overview on the current state of the art of modeling drug release from delivery systems, which are predominantly controlled by diffusional mass transport.
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Hydrogels: swelling, drug loading, and release.
TL;DR: This review summarizes the compositional and structural effects of polymers on swelling, loading, and release and approaches to characterize solute release behavior in a dynamic state.
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Mass transport Phenomena and Models: Theoretical Concepts
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Incorporation of drugs in an amorphous state into electrospun nanofibers composed of a water-insoluble, nonbiodegradable polymer.
Geert Verreck,Iksoo Chun,Joel Rosenblatt,Jef Peeters,Alex Van Dijck,J. Mensch,M. Noppe,Marcus E. Brewster +7 more
TL;DR: Electrostatic spinning was applied to the preparation of drug-laden nonbiodegradable nanofiber for potential use in topical drug administration and wound healing to assess whether these systems might be of interest as delivery systems for poorly water-soluble drugs.
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Mechanisms of solute and drug transport in relaxing, swellable, hydrophilic glassy polymers
TL;DR: In this paper, the effects of polymer morphology, composition and solute properties on transport behavior were investigated for water and drug transport in crosslinked polymeric materials, and two crosslinked polymer systems, poly(2-hydroxyethyl methacrylate) (P(HEMA-co-MMA)) and polyvinyl alcohol (PVA), were used in water transport and drug release experiments.
References
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Journal ArticleDOI
Mechanism of sustained‐action medication. Theoretical analysis of rate of release of solid drugs dispersed in solid matrices
TL;DR: The analyses suggest that for the latter system the time required to release 50% of the drug would normally be expected to be approximately 10 per cent of that required to dissolve the last trace of the solid drug phase in the center of the pellet.
Book
Membrane Technology and Applications
TL;DR: Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.
Journal ArticleDOI
A simple equation for description of solute release I. Fickian and non-fickian release from non-swellable devices in the form of slabs, spheres, cylinders or discs
TL;DR: In this paper, a simple exponential relation Mt/M∞ = ktn is introduced to describe the general solute release behavior of controlled release polymeric devices, where Mt is the fractional release, t is the release time, k is a constant, and n is the diffusional exponent characteristic of the release mechanism.