Formulation and Evaluation of Spironolactone Microspheres using natural and synthetic polymers as a Carrier

Abstract

The  present  study  reports  a  novel  attempt to prepare microspheres of the diuretic drug spironolactone by using natural ,semisynthetic and synthetic polymers as carrier. Microspheres were prepared by solvent evaporation method using an acetone / liquid paraffin system and Phase separation coacervation method using petroleum ether and coconut oil as dispersion and continuous phase systems. n-hexane was added to harden the microspheres. The prepared microspheres were evaluated for their micromeritic properties, drug content and encapsulation efficiency and characterized by Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The in vitro release studies was performed by buffer change method to mimic Gas Intestine Tract(GIT) environment in pH 1.2, carbonate buffer (acidic) and pH 7.4, phosphate buffer (Alkaline). The prepared microspheres were yellow, free flowing and spherical in shape. The mean particle size of the microspheres was found in the range of 150 to 408μm.. The drug-loaded microspheres showed 82-91% of entrapment and release was extended up to 6 to 12 h releasing 77% of the total drug from the microspheres. The infrared spectra showed stable character of Spironolactone in the drug-loaded microspheres and revealed the absence of drug-polymer interactions. Scanning electron microscopy study revealed that the microspheres were spherical and porous in nature. The best-fit release kinetics was achieved with Koresmeyer-Peppas plot followed by zero order and First order. The release of Spironolactone was influenced by the drug to polymer ratio and particle size & was found to be both diffusion and dissolution controlled.