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

Purpose: The aim of this study was to formulate and evaluate microspheres as controlled releasepreparations of a highly water-insoluble drug, Indomethacin, using natural polymer, Egg albumin; semisynthetic polymer, Ethyl cellulose and Synthetic polymer, Meth acrylic acid esters (Eudragit L 100) as theretardant materials.Methods: Microspheres were prepared by solvent evaporation method using an acetone / liquid paraffinsystem and Phase separation co-acervation method using petroleum ether and coconut oil as dispersionand continuous phase systems. Magnesium stearate was used as the droplet stabilizer and n-hexane wasadded to harden the microspheres. The prepared microspheres were evaluated for their micromeriticproperties, drug content and encapsulation efficiency and characterized by Fourier transform infraredspectroscopy (FT-IR), and scanning electron microscopy (SEM). The in vitro release studies was performedby 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 meanparticle size of the microspheres was found in the range of 150 to 400μm. The drug-loaded microspheresshowed 70-86% of entrapment and release was extended up to 6 to 8 h releasing 86% of the total drug fromthe microspheres. The infrared spectra showed stable character of Indomethacin in the drug-loadedmicrospheres and revealed the absence of drug-polymer interactions. Scanning electron microscopy studyrevealed that the microspheres were spherical and porous in nature.Conclusion: The best-fit release kinetics was achieved with Koresmeyer-Peppas plot followed by zero orderand 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.