Self-association of Verapamil in Aqueous Electrolyte Solution

Abstract

The self-association of the amphiphilic drug verapamil hydrochloride in water and in the presence of added electrolyte (0.0–0.009 mol kg−1 NaCl) has been studied by light-scattering and NMR techniques. Critical micelle concentrations were determined from inflections in the data from both techniques. Aggregation numbers determined by the application of mass action theory to the concentration dependence of 1H NMR chemical shifts were in agreement with values from static light scattering and indicated very limited association (aggregation numbers between 2 and 4).