Simultaneous determination of atorvastatin calcium and ramipril in capsule dosage forms by high-performance liquid...

Two simple and accurate methods to determine atorvastatin calcium and ramipril in capsule dosage forms were developed and validated using HPLC and HPTLC. The HPLC separation was achieved on a Phenomenex Luna C18 column (250 x 4.6 mm id, 5 microm) in the isocratic mode using 0.1% phosphoric acid-acetonitrile (38 + 62, v/v), pH 3.5 +/- 0.05, mobile phase at a flow rate of 1 ml/min. The retention times were 6.42 and 2.86 min for atorvastatin calcium and ramipril, respectively. Quantification was achieved with a photodiode array detector set at 210 nm over the concentration range of 0.5-5 microg/mL for each, with mean recoveries (at three concentration levels) of 100.06 +/- 0.49% and 99.95 +/- 0.63% RSD for atorvastatin calcium and ramipril, respectively. The HPTLC separation was achieved on silica gel 60 F254 HPTLC plates using methanol-benzene-glacial acetic acid (19.6 + 80.0 + 0.4, v/v/v) as the mobile phase. The Rf values were 0.40 and 0.20 for atorvastatin calcium and ramipril, respectively. Quantification was achieved with UV densitometry at 210 nm over the concentration range of 50-500 ng/spot for each, with mean recoveries (at three concentration levels) of 99.98 +/- 0.75% and 99.87 +/- 0.83% RSD for atorvastatin calcium and ramipril, respectively. Both methods were validated according to International Conference on Harmonization guidelines and found to be simple, specific, accurate, precise, and robust. The mean assay percentages for atorvastatin calcium and ramipril were 99.90 and 99.55% for HPLC and 99.91 and 99.47% for HPTLC, respectively. The methods were successfully applied for the determination of atorvastatin calcium and ramipril in capsule dosage forms without any interference from common excipients.