Spectrophotometric determination of phenylephrine hydrochloride in pharmaceutical preparations by oxidative coupling reaction

Abstract

Phenylephrine is a medication mainly applied as a decongestant to relieve hemorrhoids, increase blood pressure, and dilate the pupil. It is the first-line choice for prevention and treatment of hypotension during spinal anesthesia for cesarean section. However, many methods were used for the determination of this drug and its properties. This paper proposes a method that uses N, N dimethyl-p-phenylenediamine dihydrochloride as a new chromogenic reagent (NNDPH). This method is based on the oxidative coupling reaction of phenylephrine with N, N dimethyl-p-phenylenediamine dihydrochloride with ferric chloride in basic media to form green-blue soluble dye product. The outcomes demonstrate that the maximum absorption is at 680 nm, molar absorptivity of 5.54 × 103 mol-1.cm-1, and Sandell’s sensitivity of 0.038 µg.cm-2. The concentration range of 4 to 22 µg.mL-1 of the product is conformable to Beer’s law. Furthermore, it is applied successfully for estimating the drug properties on a simple condition or pharmaceutical preparations.