title: Good performance of an immunoassay based method for nevirapine measurements in human breast milk.
abstract: BACKGROUND
  Understanding the distribution of antiretro-virals in breastfeeding HIV-positive mothers is essential, both for prevention of mother-to-child HIV transmission and for research on the development of drug resistance. The ARK nevirapine (NVP)-test is an immunoassay method for nevirapine measurements, developed and validated for plasma use. In this study, the ARK NVP-test was evaluated for measurement of nevirapine concentrations in breast milk. High performance liquid chromatography (HPLC) is the method currently used to determine nevirapine in breast milk. This method, however, requires complicated extraction techniques. The ARK method employs an immunoassay technology and requires a small sample volume (40 μL) and no pre-treatment of the samples.
  
  
  METHODS
  Commercial enzyme and antibody were used and calibration standards and quality controls were prepared from pooled breast milk from HIV-uninfected women. Clinical samples from HIV-infected women receiving a single-dose of nevirapine were analyzed.
  
  
  RESULTS
  Precision and accuracy were evaluated with two concentrations of quality control materials analyzed in three replicates on four different days and was <4%, and between 96.5% and 104.6%, respectively. Clinical samples were analyzed and CVs ranged from 0.0% to 11.1%. The median nevirapine concentration in breast milk 1 week post-partum was 0.29 μg/mL (range 0.11-0.90 μg/mL) in women treated with a single-dose of nevirapine.
  
  
  CONCLUSIONS
  The ease of use and small sample volume makes the ARK assay an attractive alternative to HPLC analyses for determinations of nevirapine concentrations in breast milk.
authors.affiliation: Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark. ksalado@hotmail.com
authors.forename: Kirsten
authors.initials: K
authors.lastname: Salado-Rasmussen
authors.forename: Zahra Persson
authors.initials: ZP
authors.lastname: Theilgaard
authors.forename: Mercy
authors.initials: M
authors.lastname: Chiduo
authors.forename: Court
authors.initials: C
authors.lastname: Pedersen
authors.forename: Jan
authors.initials: J
authors.lastname: Gerstoft
authors.forename: Terese Lea
authors.initials: TL
authors.lastname: Katzenstein
mesh_terms: D002138:Calibration; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D057230:Limit of Detection; D008895:Milk, Human / Q000737:chemistry*; D019829:Nevirapine / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results
chemical_list: D019829:Nevirapine