TLC–Densitometric method for the simultaneous estimation of Glimepiride and Linagliptin used in treatment of Diabetes

Combination of Glimepiride and Linagliptin is prescribed in treatment of type 2 diabetes. The present work represents an accurate, precise, and specific high–performance thin layer chromatographic method for the estimation of Glimepiride and Linagliptin in combined dosage form. Pre–coated silica gel G60 F254 aluminum sheet were used as stationary phase and mixture of Methanol: Toluene (2:8, v/v) was used as mobile phase. The method was found to be linear in the range of 20–120 ng/band for Glimepiride and 100–600 ng/band for Linagliptin with a correlation coefficient (r2) 0.9952 for Glimepiride and 0.9936 for Linagliptin. The proposed method was validated with respect to linearity, accuracy, precision, robustness, and specificity as per ICH Q2 (R2) guideline. Forced degradation study was carried out to find out the intrinsic stability of both the molecules. Glimepiride was significantly degraded in acid, alkali, oxidative, thermal, and photo stress conditions while Linagliptin was found to be stable. Drug content in synthetic mixture is determined by proposed method where it exhibited good recovery which shows the applicability of method for the analysis of both the drugs in combined formulation.