Quantification of darunavir (TMC114) in human plasma by high-performance liquid chromatography with ultra-violet detection

A precise and accurate high-performance liquid chromatography (HPLC) method with UV detection has been developed and validated for darunavir, a peptidic protease inhibitor. An internal standard, methylclonazepam, was added to 100 μL of plasma before a solid-phase extraction on C18 Bond Elut column. The eluted solutions were evaporated to dryness and reconstitued with 100 μL of mobile phase before being injected in the chromatographic system. The separation was performed on a C8 column using an acetonitrile and ultrapure water mixture (40:60, v/v) as mobile phase. All compounds were detected at a wavelength of 266 nm. The method was linear and validated over a concentration range of 0.25–20 mg/L. The within-day precision, ranged from 3.0 to 7.9%, while the within-day accuracy ranged from −11.4 to 0.5%. The between day precision and accuracy were respectively less than 13.7 and −11.4%. The mean recovery was 75.7% for darunavir and 66.7% for methylclonazepam. This method provides a useful tool for therapeutic drug monitoring in HIV patients.