Preparação de particulados de celulose de fibra de bananeira carboximetilada visando estudos de liberação prolongada de fármaco

Abstract

Systems of drug release made of cellulose obtained from renewable sources have been widely used in several works. In this context, this project aimed to produce micro particulates from the cellulose extracted from the banana pseudo stem fibers. In order to evaluate the quality of the cellulosic fiber obtained, some characterizations were performed, in which the banana pseudo stem fibers presented 10.12% of total extractive, 37.55% of cellulose and 26.68 % of hemicelluloses. Total lignin content was 13.66%. After the use of 3% sodium hydroxide solution, it was obtained treated fibers (FT) with a Kappa number value of 5.34. The micro Kappa number was 0.17 in the bleached treated fibers (FTB), which indicates that the lignin was practically removed. The crystallinity indexes for crude fiber (FB), FT and FTB were 44%, 45% and 65% respectively, evidencing that the removal of non-cellulosic components is responsible for the observed index increase. The particulates produced from the carboxymethylation of the FTB by the method of biomineralization were almost spherical, with dimensions varying from 1μm to 5μm, which were measured by scanning electron microscopy. The thermogravimetry and derivative thermogravimetry showed that the removal of non-cellulosic components of the banana pseudo stem fibers altered the thermal stability of the fibers, since the FB, FT, and FTB presented maximum decomposition temperatures (TMÁX) of 304, 353 and 340 ºC, respectively. The carboxymethylcellulose (CMC), CMC/CaCO3 (100) and CMC/CaCO3 (50) had maximum decomposition temperatures (TMÁX) of 261, 288 and 291 ºC, respectively. This result evidenced that the presence of the inorganic complexant increased the thermal stability of the synthesized particulates. In the kinetic study of release of thiamine hydrochloride, performed in buffer solution pH = 6.5, the load of inorganic complexant used during the synthesis of the particles affects the release kinetics, as seen by the kinetic constants K1 and K2 which are involved in the two release steps, according to the Korsmeyer-Peppas model. Furthemore, the kinetic study of the release of thiamine hydrochloride showed that the CMC particulate system of the banana pseudo stem fibers present a good potential to be explored.