Formulation and Evaluation of Spray Dried Microspheres of Controlled Release Ramipril

Abstract

The present study sought to develop and evaluate spray-dried microspheres of chitosan and xanthan gum for controlled release of ramipril, a widely used antihypertensive drug. The prepared microspheres were characterized by particle size analysis, scanning electron microscopic studies, differential scanning calorimetric analysis, Fourier transform infrared spectroscopy analysis, X-ray diffraction studies, drug entrapment efficiency, and in-vitro drug release study. The prepared microspheres were spherical in shape and freely flowing. The size of the microspheres was in the range of 25.7 to 47.4 µm and the drug entrapment efficiency was in the range of 74.68% to 90.44%. TheDSC analysis and X-ray diffraction studies indicated that the drug was uniformly dispersed in amorphous state in the microspheres. The in-vitro drug release indicated that the spray-dried microspheres prepared with chitosan alone were not suitable for controlled released delivery of drug as maximum amount of drug was released within 5 hrs. Whereas microspheres prepared by xanthan gum released small amount of drug within 5 hrs and more amount of drug was controlled released that fit the therapeutic needs. Drug release mechanism followed non-Fickian transport. These suggest the formulation potential of chitosan and xanthan gum for spray-dried microspheres for controlled release of ramipril