Simultaneous Determination of Atorvastatin and Aspirin in Human Plasma by LC-MS/MS: Its Pharmacokinetic Application

Abstract

A simple, rapid, and sensitive liquid chromatography tandem mass spectro-metric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin and aspirin in human plasma using a polarity switch. Proguanil and furosemide were used as the internal standards for the quantification of atorvastatin and aspirin, respectively. The analytes were extracted from human plasma by the liquid-liquid extraction technique using methyl tert-butyl ether. The reconstituted samples were chromatographed on a Zorbax XDB Phenyl column by using a mixture of 0.2% acetic acid buffer, methanol, and acetonitrile (20:16:64, v/v) as the mobile phase at a flow rate of 0.8 mL/min. Prior to detection, atorvastatin and aspirin were ionized using an ESI source in the multiple reaction monitoring (MRM) mode. The ions were monitored at the positive m/z 559.2→440.0 transition for atorvastatin and the negative m/z 179.0→136.6 transition for aspirin. The calibration curve obtained was linear (r(2) ≥ 0.99) over the concentration range of 0.20-151 ng/mL for atorvastatin and 15.0-3000 ng/mL for aspirin. The method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 3.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The proposed method was found to be applicable to clinical studies.

Keywords: Acetylsalicylic acid; Aspirin; Atorvastatin; Chromatography; Liquid–liquid extraction; Pharmacokinetics.

Fig. 1.

Chemical structures of atorvastatin, aspirin, proguanil, and furosemide.

Fig. 2.

Typical MRM chromatograms of atorvastatin (left panel) and IS (right panel) in (A) human blank plasma; (B) human plasma spiked with IS; (C) an LLOQ sample along with IS; and (D) a 1.5 h plasma sample (10.1 ng/mL) showing atorvastatin peak along with IS obtained following oral administration of 20 mg of atorvastatin tablet to a healthy volunteer.

Fig. 3.

Typical MRM chromatograms of aspirin (left panel) and IS (right panel) in (A) human blank plasma; (B) human plasma spiked with IS; (C) an LLOQ sample along with IS; and (D) a 1.5 h plasma sample (304 ng/mL) showing aspirin peak along with IS obtained following oral administration of 75 mg of aspirin tablet to a healthy volunteer.

Fig. 4.

Mean plasma concentration–time profile of atorvastatin (A) and aspirin (B), in human plasma following oral dosing of atorvastatin (20 mg) and aspirin (75 mg) tablet to healthy volunteers (n = 6).