Formulation Development of Sustained Release Matrix Tablet Containing Metformin Hydrochloride and Study of Various Factors Affecting Dissolution Rate

Original Research Article Metformin hydrochloride (MET) is an oral hypoglycaemic agent which improves glucose tolerance in patients with type 2 diabetes and diminishes basal plasma levels of glucose. The aim of this study was to develop and optimize MET matrix tablets for SR application. The SR matrix tablet of MET was prepared by wet granulation technique using Sodium carboxymethyl cellulose and hydroxyl propyl methylcellulose of different viscosity grades (HPMC K4M, HPMC K15M, and HPMC K100M). The influence of varying the polymer ratios was evaluated. The excipients used in this study did not modify physicochemical properties of the drug. MET has relatively short plasma half-life, low absolute bioavailability. The need for the administration 2 to 3 times a day when larger doses are required can decrease patient fulfilment. SR formulation that would maintain plasma level for 8-12 h might be sufficient for daily dosing of MET. SR products are needed for MET to prolong its duration of action and to improve patient compliances. The developed formulation of tablet (F1 to F6) was evaluated for pre-compression and post–compression method. The results of all parameter were found to be within the limits. The optimized formulations (F6) were subjected to stability studies and shown there were no significant changes in drug content, physicochemical parameters and release pattern. Assay of the pure drug and formulation was carried out by using UV and RP-HPLC method. The in vitro drug dissolution study was carried out using USP apparatus Type I, Basket method and the release mechanisms were explored. Mean dissolution time is used to characterize drug release rate from a dosage form and indicates the drug release is retarding efficiency of the polymer. The in vitro release studies exhibits the release up to 94.8%, over a prolonged period of time which confirms the extended release profile of formulation (F6) after 12 hrs as compared to marketed formulation, invitro drug release data obtained were fitted to various release model excess the possible mechanism of the drug release. In conclusion, development of MET SR tablets is a good approach to sustain the release rate to overcome frequent administration and also to release the drug for prolongs period thus maintaining plasma level above the MEC for desired time period. Further the efficacy of the developed formulations has to be assessed by pharmacokinetic studies in humans. Keyword: Metformin hydrochloride, SR matrix tablet, HPMC K100M, Wet granulation technique, In vitro drug dissolution. Copyright @ 2019: This is an open-access article distributed under the terms of the Creative Commons Attribution license which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use (NonCommercial, or CC-BY-NC) provided the original author and source are credited.