A new application of isoindole fluorophore derivative in Sitagliptin anti-diabetic medication assay: application to dosage forms and biological fluids evaluation.

Dipeptidyl peptidase-4 enzyme suppressant is a unique category of oral antidiabetic medication. Sitagliptin (STG) is a perfect member of this category and is pharmaceutically marketed alone or in combination with metformin. Here, the ideal usage of an isoindole derivative was generated for STG assay in a feasible, easy-to-use, economic, and affordable way. STG as an amino group donor can form a luminescent derivative; isoindole upon interaction with o-phthalaldehyde and the existence of (2-mercaptoethanol) 0.02% v/v as a thiol group donor. Excitation (339.7 nm) and emission (434.6 nm) wavelengths were used to monitor the isoindole fluorophore yield, moreover, each experimental variable was carefully investigated and adjusted. The calibration graph was produced by plotting fluorescence intensities against STG concentrations, and controlled linearity was seen at concentrations values ranging from 50 to 1000 ng/mL. A thorough analysis of the ICH guidelines was employed to prove the technique validation. The implementation of the present technique was extended successfully into the evaluation of various types of STG dose forms and spiking samples of human plasma and urine. The developed technique was shown to be an effective, simple, and quick replacement for quality control and clinical study evaluation of STG.