Indomethacin loaded alginate microparticles were prepared by using the ionic cross linking technique using calcium chloride. The effect of sodium alginate concentration was evaluated with respect to particle shape, entrapment efficiency and in vitro release behaviors. The effect of various concentrations of hydroxyl propyl methylcellulose (HPMC 50cps), polyvinylpyrrolidone (PVP K 25) and calcium chloride on the % drug release was also evaluated. By changing formulation parameters the shape and entrapment efficiency were found to be altered. The desired in vitro release profile was obtained by altering the sodium alginate concentration only. The kinetic modeling of the release data indicates that indomethacin release from alginate microparticles follows first order and the release mechanism was case II transport. The fourier transform infrared spectroscopy (FTIR) study confirmed the absence of any drug polymer interaction. Diffrential scanning calorimetry (DSC), X-ray diffraction (XRD) studies revealed that the crystallinity of the drug decreases when loaded in the alginate microparticles. Indomethacin associated adverse effects can be reduced by using controlled release formulations. The controlled release microparticles loaded with indomethacin were evaluated for various in vivo parameters such as ulcer index, lipid peroxidation (LPO), reduced glutathione (GSH) and catalase (CAT) levels. Ulcer index and other biochemical parameters (except GSH levels) were found to be significantly different when compared to pure drug which is desirable. Therefore, loading of indomethacin in controlled release microparticles found to have fewer side effects when compared to pure drug which is clearly evident from various in vivo tests conducted. Both in vitro and in vivo studies confirmed beyond doubt the advantage of control release of indomethacin in the effective therapeutic management of inflammation and proved to be better than conventional dosage form with substantial decrease in side effects.

Keywords: Controlled release, Indomethacin, Microparticles