The construction and characteristics of drug-selective electrodes. Applications for the determination of complexation constants of inclusion complexes with α- and β-cyclodextrins including a kinetic study

Abstract

Ion-selective membrane electrodes selective to the drugs chlorpromazine, dicyclomine, imipramine, desipramine and propranolol hydrochlorides have been constructed using a modified poly(vinyl chloride) membrane which has ionic end-groups as ion-exchange sites and which was cast using a solid polymeric plasticiser. These drug electrodes show excellent Nernstian responses in the concentration range 10^–2–10^–7 mol dm^–3 and their selectivity coefficients with respect to each other, as well as their workable pH range have been investigated. The electrodes have also been used to determine the complexation constants of chlorpromazine and dicyclomine hydrochlorides with both α- and β-cyclodextrins. In all cases a 1:1 complex was observed. The kinetics associated with the formation of the complex involving α-cyclodextrin and dicyclomine hydrochloride have also been investigated using the ultrasonic technique.