Kinetic Spectrophotometric Determination of Betahistine Dihydrochloride and Etilefrine Hydrochloride in Pharmaceutical Formulation

Abstract

The importance of betahistine dihydrochloride as an anti-vertigo medicine and of etilefrine hydrochloride in the management of hypotension necessitates the development of a simple, sensitive and inexpensive technique for their analysis. This study reports the development of an accurate, feasible kinetic technique for their determination. It is based on the reaction of the cited drugs with 4-chloro-7-nitrobenzofurazan (NBD–Cl) in presence of 0.05 M disodium hydrogen phosphate. The absorbance was measured at 496, and 503 nm for betahistine dihydrochloride and etilefrine hydrochloride respectively, at a fixed time of 30 minutes on thermostated water bath at 90°C. The absorbance concentration plots were rectilinear over the range 0.25–7 and 3–13 μg/ml for betahistine dihydrochloride and etilefrine hydrochloride, respectively. The method has been applied successfully to commercial tablet dosage form and can be further applied for their determination on a large scale in quality control laboratories, or in small laboratories. The obtained results statistically agreed with those obtained by official titrimetric methods. The determination of the studied drugs by the fixed concentration and rate constant methods is feasible with the calibration equations obtained, but the fixed time method proves to be more applicable.