title: Determinations of zidovudine/didanosine/nevirapine and zidovudine/didanosine/ritonavir in human serum by micellar electrokinetic chromatography.
abstract: Micellar electrokinetic chromatography methods were developed and validated to separate and quantitate anti-HIV drug mixtures containing zidovudine(AZT)/didanosine(ddI)/nevirapine (mixture A) and AZT/ddI/ritonavir (mixture B) in human serum. Serum samples were prepared using a solid-phase extraction procedure. The effects of various factors such as buffer type, buffer and surfactant concentrations, and pH on the separations were investigated. The optimized resolution was achieved with a run buffer containing 18 mM sodium dodecylsulfate in 15 mM phosphate and borate buffer (pH 9.0). An uncoated 52 cm (effective length 30 cm)x50 micrometer ID fused-silica capillary operated at 30 degrees C was used in the analysis with UV detection at 210 nm. Aprobarbital was chosen as the internal standard. All analytes were separated within 14 min with a voltage of +15 kV and a current around 30 microA. The methods were validated over the range of 0.5-25.0 microgram/ml for AZT, 0.8-18.5 microgram/ml for ddI, 0.5-22.8 microgram/ml for nevirapine in mixture A and the range of 0.5-25.0 microgram/ml for AZT, 0.8-18.5 microgram/ml for ddI, 1.2-28.8 microgram/ml for ritonavir in mixture B. Intra-day and inter-day accuracy was less than 12.4% and intra-day and inter-day precision was less than 13.9% for both mixtures. Extraction recoveries of all analytes from serum were higher than 75.9%. The assay should be applicable to pharmacokinetic studies and routine monitoring of these drugs in serum.
authors.affiliation: Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, 30602-2352, Athens, GA, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Fan
authors.forename: James T
authors.initials: JT
authors.lastname: Stewart
mesh_terms: D019380:Anti-HIV Agents / Q000097:blood / Q000737:chemistry; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D016049:Didanosine / Q000097:blood* / Q000737:chemistry; D006801:Humans; D019829:Nevirapine / Q000097:blood* / Q000737:chemistry; D019438:Ritonavir / Q000097:blood* / Q000737:chemistry; D015215:Zidovudine / Q000097:blood* / Q000737:chemistry
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine; D019829:Nevirapine; D016049:Didanosine; D019438:Ritonavir