Entrecruzamiento de un almidón comercial cubano para su uso como matriz de liberación controlada de fármacos

Abstract

Crosslinking of a Cuban commercial starch with epiclorohydrin (ECH), for obtaining a polymeric matrix to be used in controlled release of drugs, was studied. Gelatinization time was previously determined at the experimental conditions lately used for ECH crosslinking of starch. The independent variables for the crosslinking study were ECH dose (percentage on starch), ammonia dose (moles of NH₃/moles of ECH) and time for ECH addition (min) in order to crosslink full or partial gelatinized starches. Crosslinking was followed by dynamic viscosity measurements. Crosslinked starches were characterized by IR and ¹³C NMR spectroscopies, scanning electron microscopy (SEM) and determining the swelling on several fluids, as simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). Maximum viscosity and crosslinking time were only significantly influenced by ECH dose. Crosslinking time ranged between 60 to 150 min, meanwhile maximum viscosity changed from 110 to 170 mPa · s . A significant high correlation between IR absorbance at 2 930 cm^-1 (corresponding to CH₂ groups) and maximum viscosity was found, indicating the possibility of measuring the crosslinking degree of starch by this technique. SEM showed crosslinked starches as relative homogeneous materials, meanwhile granules of 10 mm diameter were found in the initial starch.