A floating-type dosage form of repaglinide in polycarbonate microspheres

Abstract

ObjectiveTo prepare a floating type dosage form for the anti-diabetic drug repaglinide using polycarbonate (PC) microspheres capable of floating in the gastro-intestinal fluid to improve the biological half life and bioavailability of the drug. MethodsFloating microspheres containing repaglinide were fabricated using different ratios of PC and poly(propylene glycol) (PPG) by a solvent evaporation technique using dichloromethane as the solvent. Microspheres were characterized using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Toxicity of the microspheres was examined using NH 3T3 cells. In vitro drug release was examined in simulated gastric and intestinal fluids. ResultsMicrospheres having encapsulation efficiency (>90%) and floating ability (>70%) were obtained. DSC studies confirmed the amorphous nature of drug in the microspheres. The microspheres were non-toxic to NH 3T3 cells in vitro. In vitro release studies showed a biphasic mode of release from all formulations. ConclusionsIt was seen that the mechanism of release of repaglinide from the microspheres was diffusion controlled and Fickian in character. Incorporation of more PPG in the system and increase in the drug payload led to faster release. The system is expected to ensure retention in the gastro-intestinal tract (GIT) for longer periods.