Determination of Noramidopyrine Methane Sulfonate Sodium Salt, Pitophenone Hydrochloride and Fenpiverine Bromide in Pharmaceuticals by Ratio-Spectra Zero-Crossing Derivative Spectrophotometry

Abstract

Rapid and accurate ternary mixture analysis of noramidopyrine methanesulfonate sodium salt (N), pitophenone hydrochloride (P) and fenpiverine bromide (F), was performed. Ratio-spectra 1^st - derivative spectrophotometry by zero-crossing measurements was used due to the drugs closely overlapping absorption spectra. Neither sample pretreatment, nor separation was required. Linear calibration graphs of 1^st-derivative values at 289 nm for N, 273.5 nm for P and 248.5 nm for F, were obtained vs. concentration with negligible intercept on the y-axis, up to 40 μg/ml of each drug. Correlation coefficients were from 0.9997 to 0.9999. The limits of detection (LOD) were calculated to be 0.47 for N, 0.23 for P and 0.90 μg/ml for F. The method was successfully applied to and in commercial injections for these drugs obtaining selectivity, accuracy and precision.

Key Words:

• derivative spectrophotometry
• ratio-spectra zero-crossing
• measurements
• noramidopyrine methanesulfonate
• pitophenone hydrochloride
• fenpiverine bromide