Simultaneous determination of emtricitabine and tenofovir disoproxil fumarate in pharmaceutical preparations using spectrophotometric, chemometric and chromatographic methods

Abstract

Simple, accurate and sensitive spectrophotometric, chemometric and chromatographic methods were used for the simultaneous determination of emtricitabine (ETC) and tenofovir disoproxil fumarate (TDF) in tablets. In 1st derivative spectrophotometry, the first derivative spectra of the solution of ETC and TDF in water were recorded as ?? = 4 nm and the first derivative absor-bances were measured at the zero-crossing points at 297.3 and 281.2 nm for ETC and TDF, respectively. In ratio of the 1st derivative spectrophotometry measurements were recorded at 239.0 and 270.2 nm for ETC and TDF, respect-ively. Then analytical signals were measured at the wavelengths corresponding to either maximum or minimum for both drugs. For these spectrophotometric methods Beer?s law is obeyed in the concentration range of 2?15 ?g mL-1 for both drugs. As chemometric method, the PLS technique was used. In chroma-tographic method, the separation was achieved on a C18 column with DAD (262 nm) and isocratic elution of methanol, acetonitrile and 0.1 % orthophos-phoric acid in the volume ratio of 40:40:20, respectively, containing the mob-ile phase. The mean recovery and the relative standard deviation of the methods were found as 97.51?100.17 % and 0.55?1.26 % respectively. All these methods were statistically compared, and they were successfully applied to a pharmaceutical preparation.