Simultaneous Estimation of Lamivudine, Tenofovir Disoproxil Fumarate and Efavirenz in Bulk and Tablet Dosage Form by Cramer’s Rule

Background: Cramer's rule is one of the significant techniques applied to settle an arrangement of conditions. In this rule, the upsides of the factors in the framework are to be determined utilizing the determinants of networks. Consequently, Cramer's rule is otherwise called the determinant rule. Few analytical methods for simultaneous estimation of Lamivudine, Tenofovir disoproxil fumarate and Efavirenz available currently are UPLC, RP-HPLC which are quit affordable. UV-Visible method is also available but that are not based on Cramer’s rule which affords more accurate results in analytical research protocols. Traditional method needs to separate the LAM, TDF and EVZ before analysis. Proposed method did not need to separate these 3 drugs and only needs to prepare the sample solution directly as per given in the assay procedure and measure the absorbance at 262 nm, 247nm and 272 nm. Materials and Methods: Jasco V- 730 double beam UV- vis-spectrophotometer at wavelength range of 200-400 nm was used for research protocol. Trioday tablet containing three Anti-HIV drugs and manufactured by Cipla were used for the study. Methanol and freshly prepared distilled water was used as solvents. UV-visible spectroscopy method is applied for simultaneous estimation of Lamivudine, Tenofovir disoproxil fumarate and Efavirenz in their ternary mixture and their tablet dosage form. UV-vis-spectrophotometry is based on the additivity of absorbance of drugs. The drugs show maximum absorbance at 247 nm for Efavirenz, 262 nm for Tenofovir and 272 for Lamivudine in methanol so these wavelengths were selected for further analysis. Matrix was drawn using the standard absorptivity values obtained at all the three wavelengths and the amount of drug in the tablet dosage form was calculated by solving matrix using Cramer’s rule. The developed method was validated as per ICH guidelines. Results: The maximum wavelength found to be linear in the range of 5-30 µg/mL for Lamivudine and Tenofovir disoproxil fumarate while 10-60 µg/mL for Efavirenz. The precision was carried out at two level viz intra-day and inter-day for which the RSD was found within limit (<%2). Recovery study was carried out on the developed method and the recovery was found to be in the range of 97.5 – 102.5%. Conclusion: From analytical data it can be concluded that all the three drugs obey the Beers-Lambert’s law at these selected wavelengths of maximum. Method was found to be simple, sensitive, precise and accurate. The developed method can be applied for the routine analysis of the Lamivudine, Tenofovir disoproxil fumarate and Efavirenz in combined dosage form using Cramer’s rule.