KOPPULA TEJASWI, BRAHMAREDDY
The main objective of the present work was to develop sustained release matrix tablets of Metformin hydrochloride using different polymers viz. Hydroxypropyl methyl cellulose (HPMC) and natural gums like Guar gum and Eudragit. The tablets were evaluated for Preformulation studies like the angle of repose  bulk density, compressibility index and physical characteristics like hardness, weight variation, friability and drug content. In-vitro release of drug was performed in PBS pH 7.2 for twelve hours. All the physical characters of the fabricated tablet were within acceptable limits. The results of in vitro data of formulation F1 containing HPMC K4M as Matrix carrier and MCC as a diluent show prolonged release. But the release was slightly faster when compared to the innovator. The in vitro data of formulation F2, containing HPMC K15M as matrix carrier has shown prolonged release but at slightly faster rate when compared to the innovator. Formulation F3, containing Eudragit RLPO as matrix carrier, has shown prolonged release with 10% faster rate when compared to the innovator. F4 containing guar gum as a matrix carrier has shown prolonged release which was slightly slower when compared to the innovator. From the results above it could be understood that HPMC K4M & guar gum swell in the media and the drug entangled in its matrix is gradually leached by the media traveling the tortuous and viscous pathF8 formulation was found to be close to that of an innovator. Hence the “n” value was found to be 0.91 it shows that drug release follows super case 2 means of transport. It follows zero order release.