Dissolution Testing and Content Uniformity Analysis for Metformin Tablets Using Vildagliptin as an Internal Standard

Poor-quality medicines, brand or generic, do not meet acceptable standards. Further studies must explore the status of generic medicines in Qatar and the region, especially during the GCC crisis. The research goal is to assess whether the multi-sourced antidiabetic medication, Metformin Hydrochloride (MH) tablets marketed in Qatar and other selected worldwide locations fulfill the compendial quality control parameters and in vitro bioequivalence/interchangeability requirements. Could we safely replace branded Glucophage® with generic MH without compromising the patient’s interest? This laboratory experimental study assessed the quality control parameters and in vitro bioequivalence/interchangeability requirements of sixteen marketed products of MH tablets from 11 countries in addition to 33 MH products from Qatar’s market based on the US Pharmacopeia (USP 34) guideline recommendations. Content analysis test showed that the minimum amount was 96.9% in product S10 from the International samples and 97.1% for both Neomet (Q-N.m-1) and Glucophage (Q-G.Ph-2) from Qatar’s samples, while the maximum amount was 103.3% in product S4 (Formit 500) from the international market and 101.8% in product Q-Di-4, which is Dimet -500 from Qatar’s market. The rapid increase in the percentage of the drug release is noticed in products (S2-S6-S8-S9-S10-S12-S13-s15-S16–(Q-N.m-1)-(Q-Di-1)-(Q-Di-3)-(Q-D.ph-1)-(Q-D.ph-3)-(Q-M.ph-1)-(Q-M.ph-2)-(Q-G.m-3)) as they achieved the acceptance limit at the first time point (15 min). However, the products that showed the slowest release are (S4-S11-S14-(Q-D.Ph-3)). But, eventually, at 45 min, all the products passed the dissolution test. similarity factor results revealed that the Glucophage (S15) and (Q- G.Ph-5) were found to be the most similar products to the innovator brand Glucophage® (France) with the highest similarity factors (f2= 91.1%) and (f2 = 90.0%) respectively. This research has confirmed that not all the generics are exchangeable with the reference product Glucophage®.