Determination of Glibenclamide and Metformin Hydrochloride in active Pharmaceutical Ingredients and Combined Dosage Form Using a Stability- Indicating HPLC-UV Method

A simple, precise and accurate isocratic reversed-phase stability-indicating HPLC method was developed and validated for the determination of glibenclamide (GLB) and metformin hydrochloride (MET) in pure active pharmaceutical ingredients and commercial capsules. The method has shown adequate separation for GLB and MET from their main degradation products. Separation was achieved on An Inertsil® ODS-3 4.6 x 250 mm, 5 μm analytical column using a mobile phase consisting of methanol: phosphate buffer (pH 6.5) containing 0.01 M sodium dodecyl sulphate (50:50, v/v) at a flow rate of 1.5 ml/min and UV detection at 225 nm. The drugs were subjected to acidic, alkaline and oxidative hydrolysis to apply stress conditions. The linearity of the proposed method was investigated in the range of 50–150% of target concentration. The limits of detection were 0.01 and 0.002 μg/mL for GLB and MET, respectively. The limits of quantitation were 0.03 and 0.01 μg/mL for GLB and MET, respectively. Degradation products produced as a result of stress studies did not interfere with the detection of GLB and MET and the assay can thus be considered stability-indicating.