Utility of certain-acceptors for spectrophotometric estimation of some antihistamines

ABSTRACT

Simple and sensitive colorimetric methods have been developed for the estimation of two new antihistamines; namely, mequitazine and terfenadine. The methods involved the reaction of these drugs as n- donors with either chloranilic acid P-CA [I], tetracyano- quinodimethane TCNQ [II] or tetracyanoethylene TCNE [III] as pi- acceptors, to give a stable and highly colored radical anion. The colored products were quantified spectrophotometrically at 540 nm for [I], at 750 nm and 843 nm for [II] and at 400 nm for [III]. The optimization of the different experimental conditions has been assessed. The suggested methods were applied to assay the tested compounds in tablet forms