A Validated Stability Indicating HPTLC Method for Determination of Cephalexin in Bulk and Pharmaceutical Formulation

A simple, specific, precise and stability-indicating high performance thin layer chromatographic method of analysis of Cephalexin, both as a bulk drug and in formulation was developed and validated. The method employed TLC (Thin Layer Chromatography) aluminum plates pre-coated with silica gel 60 F254 as the stationary phase. The solvent system consisted of Ethyl Acetate : Methanol : Ammonia (6:4:1, v/v/v). This system was found to give compact spots for Cephalexin (Rf, retardation factor, value–0.56). Cephalexin was subjected to hydrolytic, oxidative, dry heat and photo-degradation as per ICH guidelines. The responses for the products of degradation were well separated from the pure drug. Densitometric analysis of Cephalexin was carried out in the absorbance mode at 260 nm. The linear regression analysis data for the calibration spots showed good relationship with (regression) r = 0.9991 in the range of 500–1500 ng (nanogram) per spot. The limits of detection and quantitation were 51.03 ng and 154.64 ng, respectively. The drug was observed to not undergo degradation with dry heat and photodegradation, but gets affected in and hydrolytic and oxidative conditions. As the method could effectively resolve the drug from its degradation products, it can be employed as a stability-indicating one.