A novel HPLC method developed and validated for the detection and quantification of atorvastatin, fluvastatin, pitavastatin and pravastatin during transdermal delivery studies

An HPLC method was developed and validated to quantify and identify several statins (atorvastatin, fluvastatin, pitavastatin and pravastatin) that were used during transdermal drug delivery. The method proved to be most effective with a Restek Ultra C₁₈, 250 x 4.6 mm, 5 μm column, a flow rate of 1.0 ml/min, UV detection at 240 nm and injection volume of 10 μl. The mobile phase used was acetonitrile/Milli-Q^® water with 0.1% orthophosphoric acid starting with 30% acetonitrile, which increased linearly to 70% (after 4 min) for up to 10 min and then re-equilibrated to start conditions. This HPLC method indicated linearity (correlation coefficient (R²) of 1) within the concentration range of 0.05-200.00 μg/ml and had an average recovery of 98-103%. Limit of detection (LOD) and limit of quantification (LOQ) showed that statins could still be identified at concentrations of 0.004-0.006 μg/ml with the exception of atorvastatin (quantifiable at 0.013-0.035 μg/ml). Specificity performed during method validation, confirmed that the method was suitable for accurate detection and quantification of the statins when included in the transdermal formulations with other excipients.