Formulation and in vitro evaluation of nateglinide microspheres using HPMC and carbopol-940 polymers by ionic gelation method

This study involves the design and characterization of Nateglinide [NAT] microspheres to enhance patient compliance. Ionic gelation technique was used to prepare Nateglinide Microspheres by using rate controlling polymers Carbopol-940 and Hydroxypropylmethyl cellulose [HPMC]. Shape and surface were evaluated with Scanning electron microscopy [SEM]. Percentage Yield, Particle size analysis, Encapsulating Efficiency, Micromeritic analysis, Fourier Transform Infra-Red Spectroscopy [FTIR], Differential Scanning Colorimetry [DSC] were done for characterization of Microspheres. Drug release studies were performed at pH 1.2 and 7.2 using USP dissolution type-2 apparatus and release rates were analyzed by the application of different pharmacokinetic models. The size of microspheres was found to be varied from 781 Micro m to 853 Micro m. Rheological studies proved excellent flow behavior while percentage yield was found to be varied from 72% to 79%. Absence of drug-polymers interactions was confirmed from FTIR and DSC results. The microspheres prepared with sodium alginate showed cracks while microspheres obtained from blend of Carbopol-940 plus sodium alginate were smooth and spherical. Maximum entrapment efficiency [71.4%] was achieved for Microspheres with Carbopol-940. The greater retardation in drug release was observed for microspheres containing Carbopol-940 and release pattern followed Higuchi kinetics model and negligible drug release was observed at pH 1.2