Abstract
The critical micelle concentration (cmc) of an amphiphilic drug amitriptyline hydrochloride (AMT) was determined in the presence of varying amounts of inorganic salts (NaF, NaCl, NaBr, LiCl, KCl), urea and thiourea over the temperature range 293-308K by conductometric and dye solubilization (ambient) techniques. The cmc values showed an inverted U-shaped behavior with temperature. In the presence of salts the cmc decreased which is explained on the basis of the nature and ion size. Urea and thiourea, at low concentrations (0.2mM urea and 0.1mM thiourea), decreased the cmc, whereas, at high concentrations, increase was observed with both the additives. Relevant thermodynamic parameters were also evaluated and discussed.