Cinética de liberação controlada de um fármaco modelo em filmes de amido

Abstract

The study of systems for controlled release of drugs is an important part of research in the pharmaceutical industry, as the use of such aids to maintain drug levels stable, reducing the risk of forgetting and degradation in the body. In order to provide controlled release of a drug, the polymer matrix must have physical and chemical conditions to afford the medicament and effectively control the release thereof to the medium. The way the medicine is released into the medium depends on processes of diffusion, swelling and erosion of this matrix, therefore the knowledge of these parameters is essential for the proper implementation of the final product. This study aimed to prepare films from cassava starch, generated by casting method using sorbitol as a plasticizer in concentration of 1% (m / m) compared to the mass of dry starch, and further study of the properties barrier in these films relative humidity (RH) of 43% and 100%. Also was to study the effectiveness in the entrapment of a drug in the polymer matrix. The barrier properties were evaluated: water absorption 43% RH with determination of the diffusion coefficient of water (D) permeable to water vapor (PVA) at 100% RH and determining the rate of transmission of water vapors ( TVA), and the swelling index of the film in distilled water (Ii). The TVA obtained and PVA films for drug-immobilized is about seven times greater than that for pure starch films, which still is about one hundred times greater than the permeability of high density polyethylene. The absorption tests enabled the quantification of the absorbed water which occurred around 3.5% for films with and without drug, but at times 40 and 20 minutes, respectively. The results for n, k and D were similar for both types of films were on average as Found: n 0.010 k 0.925 s-1 and 2.45 x 10-11 cm2.s D-1. The swelling index showed that the film gained more than five times its weight in water at seven minutes and became completely soluble after this time. Regarding the profile of drug release, it is observed from the spectrum scan of aliquots taken that all the drug is released in less than ten minutes of immersion. There thus serving the purpose of controlled release.