Using 2,4- Dinitroaniline as a Reagent for the Spectrophotometric Determination of Vancomycin Hydrochloride by Diazotization Coupling Reaction
الملخص
This paper shows the development of a spectroscopic technique with high sensitivity and accuracy for the determination of very small quantities of vancomycin hydrochloride (VH) in the raw material and pharmaceutical preparation (injection). The method is based on the diazotization coupling reaction of the drug with a diazotized 2,4-dinitroaniline reagent in an alkaline medium at room temperature, whereby 2,4-dinitroaniline is produced. This is then coupled with VH in ammonium hydroxide medium, forming an orange-colored azo dye that is water-soluble and has a maximum absorption at 462 nm. The calibration curve was linear and Beer's law was obeyed in the range of (0.25-55) µg/ml with molar absorbance 3.71 x104 l.mol-1.cm-1, and the Sandell sensitivity was 0.04 nanogram/cm². The average recovery rate was 100.53%, and the relative standard deviation did not exceed 2.1%. The method was successfully applied to determine vancomycin hydrochloride in pure form and its pharmaceutical formulation, where the results were in accordance with the standard addition method.