Cloud-Point Extraction and Spectrophotometric Determination of Nifedipine in Pharmaceutical Dosage Forms

Abstract

Sadeem Subhi Abed.

A simple, sensitive and eco-friendly cloud point extraction (CPE) technique was suggested for spectrophotometric assay of nifedipine (NIF) in pure and pharmaceutical dosage forms. The red colored product results from oxidative coupling reaction between reduced NIF and 4-aminoantipyrine (4AAP) was extracted using non-ionic surfactant (TritonX-114) and then determined at maximum wavelength 554 nm using visible spectrophotometer. All the factors that affected the efficiency of extraction such as concentrations of reagents and surfactant, time of extraction and temperature were studied. Using resultant optimum conditions, the linearity range of calibration curve was 0.8-45 μg/mL (r = 0.9976). The detection and quantification limits were of 0.395 and 1.317 μg/mL respectively with relative standard deviation best than 2%. The method was applied for assay of NIF in pharmaceutical dosage forms with percentage recovery of 99.18% and preconcentration factor about 20. The molar ratio of the result product was studied by mole ratio method using equimolar concentration of reactants indicated that the complex formed between the reduced NIF and 4AAP was 1:1 respectively. Suggested CPE method was successfully applied for the estimated of NIF in pharmaceutical tablets. The results obtained are compared with UV method (standard method) and the results indicated insignificant difference between two methods.