Design and evaluation of extended release metformin hydrochloride tablets for type II diabetis mellitus
Metformin hydrochloride tablets intended for extended release were prepared using Eudragit L 100, EudragitNE 30 D andHydroxy PropylMethyl Cellulose(HPMC)/Ethyl cellulose (EC) combination. The technique employed was wet granulation followed by compression. The in vitro release profile of the resulting tablets was evaluated in 0.1N Hcl for 2 hrs and pH 6.8 phosphate buffers for remaining hrs. Preliminary data suggested that the HPMC/EC combination of polymer showed a great promising retardant release. The other in process quality parameters were also studied for the batch tablets, which gave in vitro profiles in accordance with the theoretical release profiles for, sustained release. The release kinetics has been examined for the tablets, which obeyed the stability study, and in vitro profile limits fromthe standard point of diffusion controlled process (higuchi profile) and that of a first order kinetics. The release pattern of the drugs is uniform throughout and is reproducible. Batches 7-10 of metformin ER tablets were formulated using varying proportions of drug and HPMC K4Mratios keeping a constant ratio of ethyl cellulose. The drug is primarily granulated with ethyl cellulose and again re-granulated with HPMC K4Mfor maximumsustained release. This formulation was done with easily available&lowcost polymers, which can effectively reduce the cost of formulated product.