title: Microanalysis of the antiretroviral nevirapine in human hair from HIV-infected patients by liquid chromatography-tandem mass spectrometry.
abstract: Sufficient drug exposure is crucial for maintaining durable responses to HIV treatments. However, monitoring drug exposure using single blood samples only provides short-term information and is highly subject to intra-individual pharmacokinetic variation. Drugs can accumulate in hair over a long period of time, so hair drug levels can provide drug exposure information over prolonged periods. We now report on a specific, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method for measuring nevirapine (NVP), a widely used antiretroviral drug, levels in human hair using even a single short strand of hair. Hair samples are cut into small segments, and the drug is extracted in methanol/trifluoroacetic acid (v/v, 9:1) shaken at 37 °C in a water bath overnight, followed by liquid-liquid extraction under alkaline conditions. The extracted samples are then separated on a BDS-C(18) column with a mobile phase composed of 50% acetonitrile containing 0.15% acetic acid and 4 mM ammonium acetate with an isocratic elution for a total run time of 3 min and detected by triple quadrupole electrospray multiple reaction mode at precursor/product ion at 267.0 > 225.9 m/z. Deuterated nevirapine-d5 was used as an internal standard. This method was validated from 0.25 to 100 ng/mg using 2 mg hair samples. The accuracies for spiked NVP hair control samples were 98-106% with coefficients of variation (CV) less than 10%. The CV for incurred hair control samples was less than 7%. The extraction efficiency for incurred control hair samples was estimated at more than 95% by repeated extractions. This method has been successfully applied to analyze more than 1,000 hair samples from participants in a large ongoing cohort study of HIV-infected participants. We also showed that NVP in human hair can easily be detected in a single short strand of hair. This method will allow us to identify drug non-adherence using even a single strand of hair.
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143, USA. yong.huang@ucsf.edu
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Qiyun
authors.initials: Q
authors.lastname: Yang
authors.forename: Kwangchae
authors.initials: K
authors.lastname: Yoon
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Lei
authors.forename: Robert
authors.initials: R
authors.lastname: Shi
authors.forename: Winnie
authors.initials: W
authors.lastname: Gee
authors.forename: Emil T
authors.initials: ET
authors.lastname: Lin
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Greenblatt
authors.forename: Monica
authors.initials: M
authors.lastname: Gandhi
mesh_terms: D019380:Anti-HIV Agents / Q000032:analysis*; D002853:Chromatography, Liquid / Q000191:economics / Q000379:methods; D015331:Cohort Studies; D015658:HIV Infections / Q000188:drug therapy*; D006197:Hair / Q000737:chemistry*; D006801:Humans; D019829:Nevirapine / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000191:economics / Q000379:methods*
chemical_list: D019380:Anti-HIV Agents; D019829:Nevirapine