Simultaneous Determination of Ketoconazole, Ritonavir and Lopinavir in Solid Lipid Nanoparticles by RP-LC

Lopinavir (LPV), ritonavir (RTV) and ketoconazole (KTZ) loaded solid lipid nanoparticles (SLN) were formulated based on reported drug-drug interaction among these three drugs. In order to study the drug-drug interactions and to optimize the formulation, the in vitro release data of these three drugs from the formulation is necessary. Hence, there is a need to develop a simple, accurate and a rapid RP-LC method for the simultaneous determination of KTZ, RTV and LPV. The present method was developed using Kromasil C18 column (250 mm × 4.5 mm, 5 μm) with mobile phase consisting of acetonitrile: 0.2% triethylamine pH adjusted to 6.5 (60:40 v/v) at a flow rate of 1 mL min⁻¹. Chromatographic separation was monitored at 210 nm. Retention times of KTZ, RTV and LPV were 6.24, 8.05 and 9.23 min respectively. The method was linear over range of 0.5-10 μg mL⁻¹. This method was successfully applied for the determination of KTZ, RTV and LPV in SLN.