Determination of Nifedipine drug in Pure and Pharmaceutical Preparations by Normal Flow Injection Analysis using Sulfamethaxazole Drug as Chromogenic Reagent

Abstract

A highly sensitive  and accurate spectrophotometric method  including Technique ( Normal Flow injection analysis have been  used for determined  Nifedipine (NIF) drug  in pure and dosage forms. This approach based on the response of drug with  diazotized  sulfamethoxazole (SMZ) to form  colore   product after diazotization  of reagent and coupling reaction with drug The coloured chromogen suggests absorption maximum at 496 nm. The method  of the line conditions of response had been investigated by (1) invariable chemical  approach, by optimizing the impact of experimental variables (special bases, reagent awareness, and reaction time), (2) physical methods  including the effect of three experimental factors  (injection loop length , reaction coil ,flow rate  and reaction time). The results gave  Beer's law is obeyed over the awareness range 2-180 μg. ml-1 with an excellent determination coefficient (r²= 99.97) and molar absorptivity  3428.714.  The stoichiometry of the resulting azo dye has been also worked out and it is found to be 1:1 Nif: SMZ. This method has been carried out successfully for the determination of Nifedipine in pharmaceutical preparations (tablets).

Keywords: Nifidipine , flow injection analysis, spectrophotometry, Sulfamethoxazol ، diazotization.