Pectin-based microspheres for colon-specific delivery of vancomycin.

OBJECTIVES: The aim of this study was to describe a colon-specific delivery system based on pectin hydrogels formed by complexation with chitosan. METHODS: Hydrogels were prepared at different weight ratios (4 : 1, 7 : 1, 10 : 1; pectin/chitosan), loaded with vancomycin hydrochloride (2 : 1, 4 : 1; polymer/drug weight ratio) and collected by spray-drying. The microspheres obtained were characterized in terms of morphology, swelling behaviour, mucoadhesive properties and drug loading efficiency. The influence of different pectin/chitosan hydrogels on the release behaviour of microspheres at pH 2.0, 5.5 and 7.4 were evaluated in vitro with and without pectinolytic enzyme. KEY FINDINGS: The results showed that water uptake was increased by raising the environmental pH (from 2.0 to 7.4) and the pectin/chitosan weight ratio, while drug availability was increased by raising the environmental pH (from 2.0 to 7.4) and decreased by raising the pectin/chitosan weight ratio. In the presence of pectinase, the glycoside bonds of pectin were degraded and a considerable amount of drug was released in a short time. CONCLUSIONS: This study suggested that pectin/chitosan microspheres were able to limit the release of vancomycin under acidic conditions and release it under simulated colonic conditions, confirming their potential for a colon-specific drug delivery system.