Abstract

Background: The determination of antiretroviral drugs in hair is receiving considerable research interest to assess long-term adherence to antiretroviral therapy (ART). Currently in China, lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir are combined as first-line and second-line free therapy regimens and are recommended for people living with HIV (PLWH). Simultaneous determination of the 6 antiretroviral drugs in human hair is important for accurately and widely assessing long-term adherence in Chinese PLWH receiving different ART regimens.

Methods: Six drugs were extracted from 10-mg hair samples incubated in methanol for 16 hours at 37°C and then analyzed by liquid chromatography with tandem mass spectrometry using a mobile phase of 95% methanol, with an electrospray ionization source in multiple reaction monitoring and positive mode.

Results: The LC-ESI+-MS/MS method exhibited a linear range (R2 > 0.99) within 6-5000, 10-5000, 6-50,000, 12-50,000, 8-5000, and 8-12,500 pg/mg for lamivudine, zidovudine, nevirapine, efavirenz, ritonavir, and lopinavir. For all 6 drugs, the limits of quantification ranged between 6 and 12 pg/mg. The intraday and interday coefficients of variation were within 15%, and the recoveries ranged from 91.1% to 113.7%. Furthermore, the other validation parameters (ie, selectivity, matrix effect, stability, and carryover) met the acceptance criteria stipulated by guidelines of the US Food and Drug Administration and European Medicines Agency. Significant intergroup differences were observed between high-adherence and low-adherence groups, with high intercorrelations in the hair content of the 6 drugs.

Conclusions: The developed method demonstrated good reliability, to comprehensively and accurately assess adherence in PLWH receiving different ART regimens.