Analytical Method Optimization and Validation for Combined Estimation of Dolutegravir and Lamivudine Using UV and RPHPLC Techniques

Abstract

Dolutegravir and lamivudine are widely used antiretroviral agents in fixeddose combinations for the management of HIV infection. Reliable, economical, and rapid analytical methods are essential for routine quality control of these formulations. The present study aimed to develop and validate simple, accurate, precise, and cost-effective UV–Visible spectrophotometric and RP-HPLC methods for the simultaneous estimation of dolutegravir and lamivudine in synthetic mixture and pharmaceutical dosage forms. A UV spectrophotometric method based on the Q-absorbance ratio technique was developed using 290 nm as the iso-absorptive wavelength and 271 nm as the λmax of lamivudine. The linearity range for the UV method was 1–5 µg/mL for dolutegravir and 6–30 µg/mL for lamivudine. An RP-HPLC method was developed using a C18 column with detection at 290 nm. The optimized mobile phase consisted of methanol with pH adjusted to 4.6 using orthophosphoric acid, delivered at a flow rate of 1.0 mL/min. The retention times were approximately 1.7 min for dolutegravir and 1.1 min for lamivudine. Both methods were validated as per ICH guidelines for linearity, accuracy, precision, robustness, ruggedness, LOD, and LOQ. The UV method demonstrated good linearity, with recovery values of approximately 101.12% for dolutegravir and 99.98% for lamivudine. The RP-HPLC method showed linearity over 20– 100 µg/mL for dolutegravir and 120–600 µg/mL for lamivudine, with correlation coefficients of 0.998 and 0.9982, respectively. The percentage purity by RP-HPLC was 102.4% w/w for dolutegravir and 99.77% w/w for lamivudine. The LOD/LOQ values for RP-HPLC were 5.3/16.16 µg/mL for dolutegravir and 30.74/93.16 µg/mL for lamivudine. The proposed UV and RP-HPLC methods were found to be simple, rapid, accurate, precise, robust, and suitable for routine quality control analysis of dolutegravir and lamivudine in combined pharmaceutical dosage forms.