A simple spectrophotometric method for the determination of nylidrin hydrochloride, isoxsuprine hydrochloride and salbutamol sulphate in pharmaceutical preparations

A simple spectrophotometric method for the determination of nylidrin hydrochloride, isoxsuprine hydrochloride and salbutamol sulphate is described, based on measurement of the orangeyellow species produced when the drugs are coupled with diazotized benzocaine ( p-aminoethyl benzoate) in trimethylamine medium. The method is applicable over the range 1–12 μg ml for isoxsuprine hydrochloride and nylidrin hydrochloride and 1–8 μg ml for salbutamol sulphate. The method is a modification of the Bratton-Marshall reaction and is simple, reproducible, accurate and more sensitive than those cited in the literature.