Development and Validation of HPTLC Method for Simultaneous Determination of Amlodipine Besylate and Metoprolol Succinate in Bulk and Tablets

A simple, selective, precise high-performance thin-layer chromatographic method for simultaneous determination of amlodipine besylate and metoprolol succinate in bulk and pharmaceutical combined dosage form was developed and validated. The method employed HPTLC aluminum plates precoated with silica gel 60F-254 (10×10) as the stationary phase. The solvent system consisted of toluene:ethyl acetate:methanol:triethylamine (4:1:1:0.4 v/v/v). The system was found to give a compact spot for amlodipine besylate (R(f) = 0.39±0.02) and metoprolol succinate (R(f) = 0.59±0.02). Densitometric analysis of amlodipine besylate and metoprolol succinate was carried out in the absorbance mode at 254 nm. Linear regression analysis data for the calibration plots showed good linear relationship with r(2) = 0.9990±0.0013 with respect to peak area in the concentration range 400-1400 ng per spot for amlodipine besylate and r(2) = 0.9993±0.0013 with respect to peak area in the concentration range 3800-13300 ng per spot for metoprolol succinate. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 39.99 and 121.20 ng per spot for amlodipine besylate and 234.31 and 710.03 ng per spot for metoprolol succinate, respectively. Statistical analysis proved that the method is selective, precise and accurate for the estimation of amlodipine and metoprolol.