Determination of tenofovir in human plasma by high-performance liquid chromatography with spectrofluorimetric detection

A sensitive high-performance liquid chromatography method was developed with spectrofluorimetric detection for the determination of tenofovir, a new HIV reverse transcriptase inhibitor, in human plasma. After precipitation of 200 μl of plasma samples by methanol and evaporation of the supernatant, fluorescent derivatized compounds were obtained by a 40-min incubation at 80 °C with chloroacetaldehyde 0.34% at pH 4.5. The assay was performed isocratically using 5 mM Na2HPO4 (pH 6), containing tetrabutylammonium (TBA) chloride 5 mM, and acetonitrile (85:15, v/v) as mobile phase, and a Cluzeau C8 plus satisfaction column maintained at 35 °C. Detection was performed at excitation and emission wavelengths set at 236 and 420 nm, respectively. In these conditions, tenofovir can be separated from adefovir, the internal standard, and endogenous substances. The method was found to be linear and has been validated over a concentration range of 5–1000 μg/l. The average coefficient of the limit of quantification (5 μg/l) was 5.38% and at this concentration, a signal-to-noise ratio of 500 was measured