Improved method for concurrent quantification of antiretrovirals by liquid chromatography-tandem mass spectrometry

Therapeutic drug monitoring (TDM) is becoming more widespread to optimize the treatment of patients with HIV/AIDS. The analytic component of TDM requires a drug assay with high specificity, small sample volume requirements, reasonable cost, and rapid turnaround time. This study modified a procedure for the concurrent measurement of 15 antiretrovirals by tandem mass spectrometry. The upper limit of the calibration curves was extended to 10,000 ng/mL, and the matrix for standards was changed from methanol to serum. Also, an additional drug, tenofovir, a nucleotide reverse transcription inhibitor, was included in the revised/improved method. Calibration curves showed good linearity between a concentration range of 100 and 10,000 ng/mL (r > 0.997 for all drugs). Accuracy was assessed by correlation of the calibrators with proficiency testing samples spiked with known drug concentrations and yielded results within 8% of the target values.