Stability-indicating method for the determination of assay and quantification of impurities in amlodipine–atorvastatin combination dosage form by RP-HPLC

ABSTRACT

A simple stability-indicating RP-HPLC method was developed and validated for quantification of amlodipine, atorvastatin, and its impurities on Waters HPLC using Unisol C₁₈ 5 µm, 250 × 4.6 mm column in their combined tablet dosage as per ICH guidelines. The gradient (T/%B) at 0/42, 18/42, 22/75, 30/75, 32/42, and 35/42 of 40 mM 4.7 pH ammonium acetate as mobile phase A and acetonitrile as mobile phase B of flow rate 1.5 mL/min and 240 nm wavelength. Peak purity compiled for amlodipine and atorvastatin in all stressed conditions. For impurities: Precision was found in between 1.5 and 3.6%. The limit of detection and quantification for amlodipine, amlodipine impurity A, and atorvastatin was found to be 0.06 and 0.18 µg/mL, for atorvastatin Impurity A, B, C, and H was determined as 0.04 and 0.11 µg/mL, for Atorvastatin Impurity D was measured as 0.11 and 0.28 µg/mL, respectively. The linear regression achieved >0.9999 from 0.22 to 7.5 µg/mL. Recovery was observed in between 97 and 101%. For assay: Precision was determined in between 0.1 and 0.2%. The linear regression achieved >0.9999 for amlodipine and atorvastatin. Recovery ranged from 100 to 101%. The validated method was found to be accurate, precise, reliable, and robust to determine the assay as well as impurities in amlodipine–atorvastatin combination dosage formulation.

GRAPHICAL ABSTRACT

KEYWORDS:

• Amlodipine
• atorvastatin
• ICH guidelines
• recovery
• stressed conditions
• validated method

Acknowledgment

The authors express their gratitude to the Department of analytical research and development of Ashland India Private Limited, Hyderabad, Telangana, India for the backing regarding research facilities and samples.