A new derivative and non-derivative UV-spectroscopic approach for quantification of simvastatin and sitagliptin in bulk and pharmaceutical formulation
Rama Rao Nadendla, Abhinandana Patchala
Simple accurate and precise spectrophotometric methods have been developed for the simultaneous estimation of simvastatin (SIMV) and sitagliptin (SITA) by employing four different analytical UV-Spectroscopic methods. From them method A was simultaneous equation method involves formation and solving the simultaneous equation using 238 nm and 267 nm as two wavelengths for simvastatin and sitagliptin respectively. Method B related to first order derivative spectrophotometry. The first order derivative absorption at 230 nm (zero crossing point of SITA) was used for SIMV and 275nm (zero crossing point of SIMV) was used for SITA. Method C is simultaneous estimation of simvastatin and sitagliptin by using dual-wavelength method. Method D involved in Q-absorption analysis based on the measurement of absorbance at two wavelengths that is the λmax of SITA 267 nm and iso -absorptive point of both drugs at 250 nm. Two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the second drug. At wavelengths 225 and 248 nm SITA had equal absorbance values; therefore, these two wavelengths have been used to determine SIMV; on a similar basis 254 and 274 nm were selected to determine SITA in their binary mixtures. The four methods were obeyed the Beer’s law in the concentration range of 3-15 μg/ml for SIMV and 50-150 μg/ml for SITA.