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
More filters
Book ChapterDOI
Influence of Gel and Solute Structure on In Vitro and In Vivo Release Kinetics From Hydrogels
TL;DR: In this article, the authors investigated the influence of gel structure on the diffusion characteristics of solutes through poly(2-hydroxyethyl methacrylate) (polyHEMA) hydrogels and found that diffusion mechanism was influenced by the nature of the water within the gel, and the average pore size of the network.
Journal ArticleDOI
Analgesic molecules interleaved between layered double hydroxide: Exchange versus in situ reaction and release properties
TL;DR: In this article, a drug delivery approach for (2E)-2-cyano-3-(furan-3-yl)acrylic acid (CFAA) and the host structure, lamellar double hydroxides (LDH) of the hydrotalcite type, as a vector were considered, and the organic compounds were prepared by Knoevenagel condensation between cyanoacetic acid and an aldehyde.
Book ChapterDOI
The Release of 5-Fluorouracil from Polycaprolactone Matrices
TL;DR: In this article, the authors compared the release of 5-fluorouracil from monolithic dispersions in poly(caproiactone), [FUPC], and compared with the release from the copolymers of 1-(N-2-ethylmethacryIcarbamoyl)-5fluoroursacil, [EMCF], with methyl methacrylate, [MMA].
Journal ArticleDOI
Fabrication and in vitro evaluation of bidirectional release and stability studies of mucoadhesive donut-shaped captopril tablets.
Asim Sattwa Mandal,S. Chatterjee,Kazi Masud Karim,Nikhil Biswas,Arijit Guha,Mamata Behera,Ketousetuo Kuotsu +6 more
TL;DR: Coated, mucoadhesive donut-shaped tablet is good for controlled release of drug in the stomach and indicated positive response against water impermeation.
Journal ArticleDOI
Application of the Refined Integral Method in the mathematical modeling of drug delivery from one-layer torus-shaped devices.
TL;DR: A mathematical modeling of controlled release of drug from one-layer torus-shaped devices is presented and a good agreement between the model prediction and the experimental data is observed.
References
More filters
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.