Simultaneous Determination of Sitagliptin and Metformin in Bulk and Janumet Tablets Using High Performance Liquid Chromatographic, Spectrophotometric and Chemometric-Assisted Spectrophotometric Methods
Hesham Salem
Analytical Pharmaceutical Chemistry Department
Faculty of Pharmacy
Minia, Egypt
Abstract:
Five methods were developed for simultaneous determination of Sitagliptin and Metformin without previous separation. In the first method (HPLC), a reversed-phase column and a mobile phase of acetonitrile:phosphate buffer (pH=3.5) (70:30 v/v) at 1.0 mL min-1 flow rate was used to separate both drugs and UV detection at 254 nm. In the second method both drugs were determined using first derivative UV spectrophotometry, with zero crossing measurement at 295 and 250 nm for Sitagliptin and Metformin, respectively. The third method depends on first derivative of the ratios spectra by measurements of the amplitudes at 287 nm and 252.5 for Sitagliptin and Metformin, respectively. The fourth one depend on isosbestic points at 256 and 228 nm, while the content of ciprofloxacin was determined by measuring the absolute value of the ultraviolet curves at 320 nm, without interference from Sitagliptin. The fifth method describes the use of multivariate spectrophotometric calibration for the simultaneous determination of the analyzed binary mixture where the resolution is accomplished by using classical least squares (CLS) regression analysis. Although the components show high degree of spectral overlap, they were simultaneously determined with high accuracy and without interference of pharmaceutical dosage form excipients. All the proposed methods were extensively validated. They have the advantage of being economic and time saving. All the described methods can be readily utilized for the analysis of pharmaceutical formulations. The results obtained by adopting the proposed methods were statistically analyzed and compared with those obtained by official methods.
