Newly developed method for the determination of sitagliptin phosphate using rubeanic acid as a precipitating agent via the use of ISNAG continues flow fluorimeter

Abstract

A new, a simple, sensitive and fast developed method for the estimation of sitagliptin phosphate in pure and pharmaceutical drugs (tablet). This method based on the reaction between sitagliptin phosphate and rubeanic acid to form reddish-black ppt, using ISNAG-Fluorimeter analyzer via the measure of diverged light at 90° from radiation source which is used a range of high intensity ultraviolet 184.9 nm & 253.7 nm by low-pressure mercury lamp while detector cell can detect at 410-1150 nm. The resultant of diverged light by an interaction between incident photons and precipitated particles giving rise to a longer wavelength that the detector can detected. Chemical and physical parameters were studied and optimized. The calibration graph was linear in the range of (0.03-13 ) mmol.L−1 , with correlation coefficient ( r )= 0.9881 ,linearity percentage r2%= 97.64 , L.O.D = 0.7848µg/sample and RSD lower than 0.6 % for (3&7 ) mmol.L−1 ( eight replicates) concentration of sitagliptin phosphate. This method was successfully applied for the determination of sitagliptin phosphate in two different companies of pharmaceutical drugs. A comparison was made between the newly developed method analysis with the classical method (UV-spectrophotometer by measuring of absorbance ) using standard addition method via the use of t-test, it was noticed that there was no significant difference between two methods at %95 confidence level.