High-performance liquid chromatographic determination of the antifungal drug fluconazole in plasma and saliva of human immunodeficiency virus-infected patients.

A high-performance liquid chromatographic (HPLC) assay has been developed for the determination of the antifungal drug fluconazole in saliva and plasma of patients infected with the human immunodeficiency virus (HIV). Samples can be heated at 60 degrees C for 30 min to inactivate the virus without loss of the analyte. The sample pretreatment involves a liquid-liquid extraction with chloroform-1-propanol (4:1, v/v). The chromatographic analysis is performed on a Lichrosorb RP-18 (5 microns) column by isocratic elution with a mobile phase of 0.01 M acetate buffer (pH 5.0)-methanol (70:30, v/v) and ultraviolet (UV) detection at 261 nm. The lower limit of is 100 ng/ml in plasma (using 500-microliters samples) and 1 microgram/ml in saliva (using 250-microliters samples) and the method is linear up to 100 micrograms/ml in plasma and saliva. At a concentration of 5 micrograms/ml the within-day and between-day precision in plasma are 7.1 and 5.7%, respectively. In saliva the within-day and between-day precision is 10.8% (at 5 micrograms/ml). The methodology is now being used in pharmacokinetic studies in HIV-infected patients in our hospital.