FORMULATION AND IN VITRO EVALUATION OF GASTRORETENTIVE FLOATING DRUG DELIVERY OF VALSARTAN USING HOT MELT EXTRUSION TECHNIQUE

The aim of present study is to improve the aqueous solubility of valsartan by utilizing hot melt extrusion technique (HME). Hot melt extrudates were prepared by novel polymeric matrices such as HPMCAS and Plasdone S630 copovidone at different ratios. The solubility studies of extrudates, showed a significant improvement in aqueous solubility. Gastroretentive floating tablets of valsartan using its extrusion complex with plasdone S630 copovidone were formulated by, direct compression method. The tablets comprised of HPMC K4M, HPMC K15M, as release retarding polymers to control the drug release. Preliminary trials applied to optimize the drug release profile. A 10.5 fold increase in the solubility of valsartan was observed with valsartan: plasdone S630 copovidone complex in the ratio of 1:2. Trial batches of tablets showed best results for formulation F3 (20% HPMC K15M and pregelatinized starch 12%) released 99.41% of valsartan in 20 h, with desired floating lag time (18 sec) and constantly floated on dissolution medium for more than 24 h. Accelerated stability studies were conducted at 40 plus or minus 2 degree C temperature and 75 plus or minus 5% RH to determine the effect of aging on the physical and chemical stability of the drug, the results showed no significant loss of activity of drug in the prepared formulations. From the study it was concluded that a gastroretentive floating drug delivery of poorly soluble valsartan can be formulated using hot melt extrusion technique.