Preparation and evaluation of microspheres of xyloglucan and its thiolated xyloglucan derivative

Xyloglucan is a natural polymer reported to possess mucoadhesive properties. To enhance the mucoadhesion potential, xyloglucan was thiolated with cysteine. The microspheres of xyloglucan were prepared using a biocompatible crosslinker sodium trimetaphosphate and it was optimized for formulation variables, namely polymer concentration, internal:external phase ratio and stirring speed using a Box–Behnken experimental design. The formulation was also optimized for performance parameters like entrapment, t80 and % mucoadhesion. The microspheres were characterized by Fourier transform infrared spectroscopy, DSC and SEM for the optimum formula and then were reproduced by replacing the xyloglucan with thiomer. The microspheres formed showed entrapment efficiency of about 80%, t80 of about 400 min and % mucoadhesion of 60% while same for thiomer were 90%, 500 min and 80% respectively. In oral glucose tolerance test protocol the thiomer microspheres showed significant reduction in blood glucose levels. Thus thiolated xyloglucan offers a better polymer for multiparticulate drug delivery.