Development and Validation of HPTLC and RP HPLC Methods for Simultaneous Estimation of Atorvastatin, Glimepiride, and Metformin Hydrochloride in Bulk and Combined Dosage Form

Abstract

Combined formulations of atorvastatin, glimepiride, and metformin hydrochloride are widely used for type 2 diabetes with dyslipidemia. Reliable analytical methods for simultaneous estimation are needed for quality control. To develop and validate simple, accurate, economical, and reproducible HPTLC and RP‑HPLC methods for simultaneous determination of these three drugs in bulk and combined tablet dosage form. HPTLC was performed on precoated silica gel 60F₂₅₄ aluminum plates with mobile phase water:methanol:ammonium sulphate (3.5:3.5:12.6 v/v/v) and densitometric detection at 245 nm. RP‑HPLC used a Phenomenex C₁₈ column (250×4.6 mm, 5 µm) with mobile phase 20 mM potassium dihydrogen phosphate:acetonitrile (65:35 v/v), flow rate 1.0 mL/min, UV detection at 245 nm. Both methods were validated according to ICH Q2(R1) guidelines.

HPTLC gave Rf values of 0.33±0.01 (metformin), 0.50±0.01 (atorvastatin), and 0.65±0.01 (glimepiride). Linearity ranges: 50‑350 ng/spot, 1‑7 ng/spot, and 0.1‑0.7 ng/spot respectively. RP‑HPLC gave retention times of 3.92±0.70 min (metformin), 8.51±0.51 min (atorvastatin), and 12.18±0.62 min (glimepiride). Linearity ranges: 50‑250 μg/mL, 1‑5 μg/mL, and 0.1‑0.5 μg/mL respectively. Recovery was 98‑102% with RSD<2%. Both methods were successfully applied to tablet formulation (label claim: 10 mg atorvastatin, 1 mg glimepiride, 500 mg metformin). The developed methods are simple, precise, accurate, and suitable for routine quality control analysis of the three drugs in combined dosage forms.