Handsheet Coated by Polyvinyl Acetate as a Drug Release System

The present work aims to prepare a controlled release matrix, using biodegradable materials containing different active ingredients (AI) in order to deliver only the necessary dose for a specific time and a well-defined target. The matrix is a manual sheet, composed of lignocellulosic fibers. The membrane, which regulates the release, is obtained by immersing the sheet in an emulsion of polyvinyl acetate. Different thicknesses were deposited by varying the concentration of the emulsion. Five AIs, which differ in volume and solubility, were used as probes: salicylic acid (SA), acetylsalicylic acid (ASA), metoclopramide (MCP), ketoprofen (KP), and thiocolchicoside (TCC). Kinetic studies have shown that the release of these substances is strongly related to the pH, the solubility of the AI, the thickness, and the permeability of the polymer membrane. The kinetics of release of AI are zero order in an acidic medium and complex in a basic medium. The images taken by scanning electron microscopy (SEM) show the variation in thickness with the number of layers of emulsion deposited. Our system, paper coated with a polyvinyl-acetate (PVAc) emulsion film without a coalescing agent has proven to be a promising matrix for achieving the controlled release of different IAs. It suffices only to adjust the thickness of the membrane. The process is simple and easy compared with other recently developed extended release matrices.