DEVELOPMENT AND VALIDATION OF STABILITY INDICATING HPTLC METHOD FOR ESTIMATION OF GLIMEPIRIDE AND METFORMIN HYDROCHLORIDE

An Accurate, sensitive, precise and stability indicating high performance thin layer chromatographic method has been developed and validated for the estimation of Glimepiride and Metformin hydrochloride. The method was developed using TLC aluminium plates precoated with silica gel 60F254 as the stationary phase and 0.5% Ammonium Sulfate: Methanol (7.5:2.5 v/v) as mobile phase. Densitometric analysis of Glimepiride and Metformin hydrochloride was carried out in the absorbance mode at 228 nm. The two drugs were satisfactorily resolved with RF values 0.73 and 0.45 for Glimepiride and Metformin hydrochloride respectively. Linearity was found to be 600-2100 ng/band for Glimepiride and 200-700 ng/band for Metformin hydrochloride. The method was found to be accurate, precise, and robust according to acceptance criteria. The limit of detection (LOD) was found to be 0.05 ng/band and 0.32 ng/band for Glimepiride and Metformin hydrochloride respectively. The limit of quantification (LOQ) was found to be 0.16 ng/band and 0.96 ng/band for Glimepiride and Metformin hydrochloride respectively. The proposed HPTLC method was successfully applied for the forced degradation study of Glimepiride and Metformin hydrochloride. Forced degradation study was carried out for both the drugs in oxidative condition 0.3% H2O2 for 30mins, in acidic condition 0.1 M HCl at 80 ̊C for 60min, in basic condition 0.01 M NaOH at 80 ̊C for 30 min, in thermal condition 60 ̊C for 24 hours and in photolytic condition for 24 hours. Degradation products were well separated by proposed method. INTRODUCTION Glimepiride is widely used in the treatment of non-insulin dependent Type II diabetes mellitus 1. It acts by stimulating insulin secretions from the beta cells of pancreas and is also known to increase peripheral insulin sensitivity thereby decreasing insulin resistance. It can be used in combination with metformin, thiazolidinediones, alpha-glucosidase inhibitors and insulin 2. After oral administration, it is completely absorbed from the gastrointestinal tract. Peak plasma concentration is reached 2 3 hrs after dosing. Its bioavailability changes a little with food and glimepiride (99.5%) are bound to proteins. Glimepiride is completely metabolised in liver. 1-2 The structure of glimepiride is shown in Fig.1. QUICK RESPONSE CODE DOI: 10.13040/IJPSR.0975-8232.6(3). 1222-29 Article can be accessed online on: www.ijpsr. com DOI link: http://dx.doi. org/10.13040/IJPSR.0975-8232.6(3). 1222-29 Metformin is a Biguanides derivative producing an anti hyperglycemic effect which can only be observed in man or in the diabetic animal and only when there is insulin secretion. Metformin, at therapeutic doses, does not cause hypoglycemia when used alone in man or in the non-diabetic animal, except when using a near lethal dose. Metformin has no effects on the pancreatic beta cells. The main mechanism of action of metformin is reduction of hepatic glucose output, largely by inhibiting hepatic gluconeogenesis. Metformin also slows intestinal absorption of sugars and improves peripheral glucose uptake and utilization. A very important property of this drug is its ability to modestly reduce hyperlipidemia (low-density lipoprotein [LDL] and very-low-density lipoprotein [VLDL] cholesterol concentrations fall, and highdensity lipoprotein [HDL] cholesterol rises). These effects may not be apparent until 4 to 6 weeks of use. The patient often loses weight because of loss of appetite. The ADA treatment algorithm