Produção e caracterização de matrizes modelo de triacetatos de celulose obtidos da palha de milho e diacetato comercial para liberação controlada de naproxeno

Abstract

In this work the cellulose acetate produced by homogeneous acetylation of cellulose extracted from corn stover was used to produce model systems for controlled release of Naproxen in the form of membranes and microparticles. The commercial cellulose diacetate was used as standard material in the production of membranes, and microparticles. The triacetates hydrolyzed and unhydrolyzed cellulose produced from corn stover presented degree of substitution of 2.53 ± 0.16 and 2.79 ± 0.35 respectively. The membranes were produced using the formulation acetate / solvent/naproxen to symmetric membranes acetate/solvent/water/naproxen for asymmetric membranes. The materials were characterized by scanning electron microscopy, differential scanning calorimetry and thermogravimetry, and was later evaluated the drug release kinetics. The hydrolysis process for obtaining corn straw triacetate impaired physical stability of the matrices produced with this derivative, which showed extremely fragile and brittle, making it unsuitable for use in controlled release systems. The release assays were performed with unhydrolyzed triacetate and commercial systems diacetate and the percentage of naproxen released was obtained by square wave voltammetry. For both polymers, the asymmetric membranes had higher cumulative percentage of drug released as compared to symmetric membranes. Asymmetric membranes diacetate reached about 80% release and that release was 30% to symmetric membranes. In the preparation of the microparticles were taken formulations acetate/solvent/naproxen acetate/ solvent/pore forming agent/naproxen. As solvents were used as dichloromethane for dioxane triacetate and diacetate for commercial as pore formers were inserted in formulations polyethylene glycol and water. Systems were prepared with different concentrations of naproxen in the ratio w/w acetate:drug 10:1, 2:1 and 1:1. The thermal analysis showed that the improved composition of the system polymer/drug was 10:1 w/w, since the drug does not appear melting peaks showing that the drug is molecularly dispersed in the polymer matrix. The kinetic model of drug release is broadcast solution. The particles produced with triacetate showed a release exceeding drug the particle produced commercially diacetate, where particles produced diacetate had a mean release of 2%, while the particles produced with modified triaceato reached about 25% release, featuring differences the interaction between the transparencies and the drug as well as increased stiffness of the particles produced with commercial diacetate. Modifications to polietilenogilicol and water in the particles with triacetate increased the release of naproxen, the release of the modified particles became 13% more than the release of the non-modified particles. The results show that the morphological changes in the controlled release systems are effective considering the increase in the percentage of drug release.