PREPARATION AND CHARACTERIZATION OF METHOCEL K4M, EUDRAGIT RLPO AND PEG 4000 LOADED CARBAMAZEPINE MICROSPHERES.

Modulated carbamazepine prolonged release dosage forms, microspheres have been prepared by the emulsion solvent evaporation method using Methocel K4M, PEG 4000 and Eudragit RLPO. A 22 factorial design was made by central composite design where the amount of Methocel K4M and PEG 4000 were selected as independent variables. Thirteen formulations were prepared with MDT, T50%, T80%, and swelling index as dependent variables. Data’s were analyzed statistically using linear regression model by IBM SPSS version 22. Effect of varying amount of Methocel K4M and PEG 4000 on the drug content, entrapment efficiency, swelling index, surface morphology (SEM), and in-vitro drug release rate were evaluated. Formulations with high amount of Methocel K4M showed good swelling properties. In SEM studies microspheres appeared rough and spherical in shape. Increasing amount of PEG produced pores on the surface of the microspheres due to the diffusion of polymers towards the external phase thus showing better drug release (B1, B3 & B8). Further clarification on release mechanism from spherical particles were studied using the Kopcha kinetics, Weibull model and Baker-Lonsdale model. In Kopcha kinetics all the formulations had ratio of A/B greater than 1 where release was primarily controlled by a Fickian diffusion. Weibull Model has parameters that are more sensitive to release kinetic data, the value of ? was <1 and Td value was low showing enhance drug release. In Baker-Lonsdale model most spherical matrix had uniformly distributed drugs with consistent drug release by diffusion mechanism which was seen as linear graphs.