In vitro release of metoclopramide from hydrophobic matrix tablets. influence of hydrodynamic conditions on kinetic release parameters.
There has been growing interest in the subject of drug delivery and the design and evaluation of controlled-release systems. The simplest way to control the release of an active agent is to disperse it in an inert polymeric matrix. Controlled-release systems are of interest because they are technologically simple, relatively cheap, and practically unaffected by physiological changes. In this study, a new matrix system was formed by an active principle, metoclopramide hydrochloride, scattered into a biocompatible hydrophobic polymerical mesh, polyamide 12, to achieve sustained and controlled delivery of metoclopramide hydrochloride. This research was conducted to investigate the in vitro drug release behavior from these new inert polymeric matrix tablets. The drug release process was investigated both experimentally and by means of mathematical models. Different models were applied for the evaluation of drug release data. On the basis of our results, a biexponential equation was proposed, Q=Qfast(1)(1 - e(-Kfast t)) + Qslow(2)(1 - e(-Kslow t)), in an attempt to explain the mechanism responsible for the release process. Additionally, the influence of the experimental conditions of the dissolution devices, such as rate of flow and pH of dissolution medium, on the parameters that characterize the release mechanism was studied, and it was found that the main factor was the hydrodynamic condition of rate of flow.
Comparison of the wetting behaviour of polyamides presented as particles and films—Influence of a plasma microwave treatment
The wettability of two types of polyamide powder (ORGASOL® and RILSAN), differing by their shape and chain ends, has been studied by three methods: inverse gas chromatography, capillary ascension and contact angle measurement on films obtained by the compression at room temperature of the powders. The results are compared with the contact angles measured on the films realized with the melted powders. All the techniques give the same classification of the wettability of the two kinds of polyamides but not the same absolute values of contact angles. In particular, the influence of the shape of the particles has been shown on ORGASOL® by capillary ascension and by contact angle performed on films obtained by compression at room temperature of the powder. A N2/O2 plasma treatment applied to the particles leads to an increase of the water wettability of the powders but the treatment was found less efficient than on the melt powder based films.
EVALUATION OF POLYMERIC MATERIALS. II. SCREENING OF SELECTED VINYLS AND ACRYLATES AS PROLONGED-ACTION COATINGS.
Acrylic and vinyl polymers, copolymers, and derivatives were evaluated as potential sustained-action coatings. Based on a screening of films of the polymeric materials for solubility characteristics, free film formation, and drug permeability, the n -butyl half ester of poly(methyl vinyl ether)/maleic anhydride offered the most in vitro promise of controlling drug release. The n -butyl half ester had no cumulative toxic effects based on a short-term feeding study.