Validation of Stability Indicating HPLC Method in the Application of Comparative Pharmacokinetic Studies of Atorvastatin in Different Pharmaceutical Formulations (bulk drug, tablet, and nanoemulsion)

A simple, highly sensitive, isocratic stability indicating reversed phase-high performance liquid chromatography (RP-HPLC) method with UV detection at 247 nm was developed and validated for analysis of Atorvastatin (AT). Diclofenac was used as an internal standard (IS). Retention times of the AT and diclofenac (IS) were found to be 4.2 and 8.2 min, respectively. A mobile phase consisting of 0.05 M sodium phosphate buffer and methanol (30:70 v/v) pH 4.1 at flow rate 1ml/min was employed in this study. The calibration curves were linear with regression coefficient (r) of 0.9997 ± 0.0014. The limits of detection (LOD) and the limits of quantitation (LOQ) were found out to be 5.0 and 15 ng/ml, respectively. The method was statistically validated in accordance with International Conference on Harmonization (ICH) guidelines. The proposed method is sensitive, specific and was successfully applied for the estimation of atorvastatin in pharmaceutical formulations (bulk drug, tablet, nanoemulsion) and in rat serum pharmacokinetic studies.