The Release of an Ampholytic Drug from Acrylic Films

Abstract

Benzyloxiamine was used as an ampholytic drug model to study the in vitro drug release from films in a function of pH. Two films based on commercial acrylic dispersions Scopacryl^R and Eudragit^R were used as drug carriers. The films investigated were produced by a solvent east technique. The pH into the films was adjusted at every experiment before cast

To understand the factors governing the release of the ampholytic drug its protonation/ionization macro and microconstants have been determined. The protonation macroconatants determined were log K₁= 7.80, log K₂ = 4.26 and log B₂= 12.06. The microconstants calculated were log K^f= 7.79, log K^a= 4.74, log K_a^f = 7.33 and log K_f^a = 4.29.

The release data could be interpreted by taking into account species concentrations calculated by use these constants on the one hand and the velocity and diffusion coefficients on the other.