Spectrophotometric determination of 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors in pharmaceutical preparations

Simple and accurate spectrophotometric methods are presented for the determination of five 3-hydroxy-3- methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors (statins), namely atorvastatin, fluvastatin, pitavastatin, rosuvastatin, and simvastatin, in pharmaceutical preparations. The methods are based on the reaction of drugs as n-electron donor with 7,7,8,8-tetracyanoquinodimethane as π-acceptors to give highly colored complex species. All variables were studied in order to optimize the reaction conditions. Beer’s law was obeyed in the concentration ranges 4–20 μg mL^ −1 , 4–12 μg mL^ −1 , 0.8–2.4 μg mL^ −1 , 4–14 μg mL^ −1 , and 2.5–20 μg mL^ −1 for atorvastatin, fluvastatin, pitavastatin, rosuvastatin, and simvastatin, respectively. The proposed methods were successfully applied to the pharmaceutical preparations without any interference from excipients.