Spectrofluorimetric determination of Alogliptin benzoate through condensation with ninhydrin and phenylacetaldehyde: application to dosage form and rat plasma

Alogliptin benzoate (ALG) is a dipeptidyl peptidase-4 inhibitor used to treat type 2 diabetes mellitus. In this study, a spectrofluorimetric method was developed for the derivatization of ALG to develop a fluorescent derivative. The derivatization reaction was carried out by reacting ALG with ninhydrin and phenylacetaldehyde in Teorell and Stenhagen buffer at pH 6.6. The reaction product was a fluorescent pyrrolidone derivative that was observed at lambda ex of 385 nm and lambda em of 475 nm. The effects of various experimental conditions on the derivatization reaction were investigated. The optimal conditions were found to be a reaction time of 15 min, a temperature of 80 degrees C, and a concentration of ninhydrin and phenylacetaldehyde of 1.4 mg mL-1 and 0.028% v/v, respectively. A calibration plot was constructed in the concentration range of 20-460 ng mL-1. The calibration curve had a high correlation coefficient of 0.9991 and a low detection limit of 6.57 ng mL-1. The eco-scale penalty points for the derivatization method were calculated to be 86. This indicates that the method is environmentally friendly and has a low risk of generating harmful waste. The derivatization method described in this study provides a sensitive and green method for the quantification of ALG in pure form, dosage form, spiked and real rat plasma.