Analytical study of linagliptin and metformin hydrochloride anti-hyperglycemic drugs / Nahla Fathy Abdelmohsen ; Supervised Faten Ahmed Fouad Nour Eldien , Eman Yousry Zaki , Shaban Abdallatif Abdallah

Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Analytical Chemistry

The present thesis includes a systematic study using HPLC and spectrophotometric techniques for the determination of anti- hyperglycemic drugs linagliptin (LNG) and metformin HCl (MET) A simple, precise and accurate isocratic reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed and validated for the estimation of linagliptin (LNG) and metformin hydrochloride (MET) in bulk and in tablet dosage form using an agilent TC C18 column (25 cm, 4.6 mm, 5 æm). Mobile phase consisted of 0.05 mol L-1 pentane sulphonic acid sodium salt: acetonitrile mixture (50:50 v/v), at a flow rate of 1 mL min-1 and the injection volume was 20 æL. The detection was achieved with UV detector at 225 nm. The retention time of MET and LNG was 2.87±0.06 and 4.24±0.03 min, respectively. The proposed method was validated for linearity, accuracy, precision, LOD and LOQ. The calibration was linear over the concentration range of 0.5- 500 og mL-1 for MET and 0.1-100 og mL-1 for LNG with LOD and LOQ 0.032 and 0.097 æg mL-1 for LNG and 0.0911 and 0.276 æg mL-1 for MET, respectively. Two simple, accurate and sensitive spectrophotometric methods for the simultaneous determination of LNG and MET in bulk powder and pharmaceutical formulations were developed. The first method was zero- crossing derivative spectrophotometry using first (1D), second (2D), third (3D) and fourth (4D) derivative methods. The wavelengths 311.6, 299.6, 309.9 and 304.4 nm for LNG and 257.2, 233.8, 267.0 and 264.6 nm for MET were chosen to be the optimum working wavelengths for their simultaneous determination using 1D, 2D, 3D and 4D methods, respectively. The second method was ratio spectra derivative (1DD) spectrophotometry, which was applied by measuring the amplitudes at the maximum wavelengths 312.8 and 233.8 nm for LNG and MET, respectively. The calibration curves were linear in the concentration range of 0.4-30.0 æg mL-1 for LNG and in range 1.5-30.0 æg mL-1 of MET. The analytical validations and recovery study was performed to confirm the accuracy of the proposed methods. The methods were validated according to the International Conference on Harmonization (ICH) guideline

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