Determination of saquinavir and ritonavir in human plasma by reversed-phase high-performance liquid chromatography and the analytical error function.

Two simple and reproducible high-performance liquid chromatography methods with ultraviolet detection were developed and validated for the quantitation of two protease inhibitors, saquinavir and ritonavir, in human plasma. The same single liquid-liquid extraction procedure with ethyl acetate-hexane (50:50, v/v), reversed-phase column and mobile phase were used. The analyses were accomplished using a Luna C(18) column (150 mm x 4.