Assay of ephedrine or pseudoephedrine in pharmaceutical preparations by second and fourth derivative ultraviolet spectrophotometry

Abstract

Rapid second and fourth derivative ultraviolet spectrophotometric assay procedures are described for the determination of ephedrine or pseudoephedrine in pharmaceutical formulations. The methods have been applied successfully to Ephedrine Elixir BP, Ephedrine Hydrochloride Tablets BP, Ephedrine Nasal Drops BPC, Paediatric Belladonna and Ephedrine Mixture BPC, tablets and capsules containing aminophylline and amylobarbitone and coloured syrups containing triprolidine hydrochloride and codeine phosphate. A simple solvent extraction stage avoids interference from the co-formulated drugs and colouring agents in certain of the formulations. The specificity, accuracy and precision of the methods have been assessed.