Lopinavir

To improve the solubility enhancement of solid dispersion of Lopinavir by spray-drying by adding the Soluplus as polymer that is compatible with Lopinavir, was evaluated and the process used for preparation of Spray dried solid dispersion was validated and the 1:3 ratio used for preparation of solid dispersion. Dissolution tests were carried out on several spray dried solid dispersion of Lopinavir and physical mixture. The solid dispersion characterized by DSC, XRD, % Entrapment Efficiency, solubility study, drug content determination, practical yield, dissolution studies.

A simple, precise and stability-indicating HPLC method was developed and validated for the simultaneous estimation of anti-retroviral drugs Lopinavir and Ritonavir. The separation was achieved on AgilentC8, 150mm* 4.6 ,5µ  column with isocratic flow. The mobile phase at a flow rate of 1.5ml consisted of 0.05M Potassium Dihydrogen Orthophosphate buffer and Acetonitrile: MeOH in the ratio of (80:20).The ratio of buffer: organic is (45:55).The UV detection was carried  out at 210nm. The method was successfully validated in accordance to ICH guidelines. This method was then used to study the stability aspects of both the drugs when subjected to acidic, alkaline, thermal and photo degradation condition.

A reversed phase high-performance liquid chromatographic method was developed and validated for the quantitative determination of two antiviral drugs viz. lopinavir and ritonavir. Chromatography was carried out by gradient  technique on a reversed-phase C18 Column, Phenomenex (250 x 4.6 mm, 5 µ) with mobile phase mixture of Buffer: Acetonitrile (45:55 v/v) was used as a mobile phase and the pH was adjusted into 4.5 by using with O-phosphoric acid, at a flow rate of 1.2 ml/min. The UV range was detected at 240nm for lopinavir and ritonavir respectively. The different analytical performance parameters such as linearity, precision, accuracy, and specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines. The linearity of the calibration curves for each analyte in the desired concentration range is good (r2 >0.9). The recovery of the method was between 102.1% and 100.1% for lopinavir and ritonavir respectively. Hence the proposed method is highly sensitive, precise and accurate and it successfully applied for the reliable quantification of API content in the commercial formulations of lopinavir and ritonavir. Key words: Lopinavir, Ritonavir, UV spectrophotometry, RP-HPLC.