Formulation and Evaluation of Indomethacin Microspheres using natural and synthetic polymers as Controlled Release Dosage Forms

Abstract

Purpose: The aim of this study was to formulate and evaluate microspheres as controlled release preparations of a highly water-insoluble drug, Indomethacin, using natural polymer, Egg albumin; semi synthetic polymer, Ethyl cellulose and Synthetic polymer, Meth acrylic acid esters (Eudragit L 100) as the retardant materials. Methods: Microspheres were prepared by solvent evaporation method using an acetone / liquid paraffin system and Phase separation co-acervation method using petroleum ether and coconut oil as dispersion and continuous phase systems. Magnesium stearate was used as the droplet stabilizer and 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). Results: The prepared microspheres were pale yellow, free flowing and spherical in shape. The mean particle size of the microspheres was found in the range of 150 to 400µm. The drug-loaded microspheres showed 70-86% of entrapment and release was extended up to 6 to 8 h releasing 86% of the total drug from the microspheres. The infrared spectra showed stable character of Indomethacin 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. Conclusion: The best-fit release kinetics was achieved with Koresmeyer-Peppas plot followed by zero order and First order. The release of Indomethacin was influenced by the drug to polymer ratio and particle size & was found to be both diffusion and dissolution controlled.