title: Improved fluorometric high-performance liquid chromatographic assay for (-)-carbovir in rat blood and urine.
abstract: Carbovir is a carbocyclic guanosine analogue with potent in vitro activity against the human immunodeficiency virus. All of the activity resides in the (-)-enantiomer. An ion-paired liquid chromatographic assay for (-)-carbovir was developed on a Spherisorb C8 column with fluorescence detection (275 nm excitation, 345 nm emission). Guanosine nucleosides are fluorescent at a pH less than 2.5, and fluorescence detection resulted in a four-fold improvement in the limit of quantitation (0.039 microgram/ml) compared to the previously developed assay with ultraviolet detection. Standard curves were processed with an internal standard at (-)-carbovir concentrations of 0.039-40 micrograms/ml in whole rat blood with a solid-phase extraction technique. Total variability was less than 16% at all concentrations and less than 10% at concentrations greater than 0.3 microgram/ml. Within-day variability was less than 7.5% at concentrations greater than 0.3 microgram/ml. Urine was analyzed directly after dilution and an diethyl ether wash to remove impurities. The total coefficients of variation were less than 10% from 0.5-20 micrograms/ml in urine. The concentrations of (-)-carbovir in rat blood were detectable for as long as 8 h after intravenous and oral doses of 20 and 60 mg/kg, respectively.
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis 55455.
authors.forename: R P
authors.initials: RP
authors.lastname: Remmel
authors.forename: S H
authors.initials: SH
authors.lastname: Huang
authors.forename: D
authors.initials: D
authors.lastname: Hoff
authors.forename: C L
authors.initials: CL
authors.lastname: Zimmerman
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000998:Antiviral Agents / Q000032:analysis* / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015224:Dideoxynucleosides / Q000032:analysis* / Q000097:blood / Q000652:urine; D005453:Fluorescence; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
chemical_list: D000998:Antiviral Agents; D015224:Dideoxynucleosides; C057503:carbovir