No abstract

The cloud point (CP) and thermodynamic parameters at cloud point viz., ΔsG0, ΔsH0and TΔsS0 of an amphiphilic drug amitriptyline hydrochloride (AMT) at several compositions of organic solvent‐water namely, ethylene glycol (EG) / glycerol (GL) ‐ water (WR) (0%, 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% w/w) mixed media and the effects of addition of conventional hexadecyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and gemini (14‐4‐14, 14–5‐14 and 14–6‐14) surfactants at selected compositions of organic solvent‐water media (0%, 5%, 10%, 15% and 20%, w/w) have been studied at a pH 6.7. Conductivity measurements were done to determine the critical micelle concentration (cmc) and degree of counterion dissociation (α) of AMT in water and different weight% of binary mixture ranging from 0% to 25% of EG/GL at 30 °C. It is observed that the micellization of AMT molecules is affected through an indirect, solvent‐mediated mechanism with the increase in their binary mixture due to lowering of dielectric constant of the mixed media. As a result, inter / intra electrostatic repulsion in the drug‐micellar head groups increases raising the cmc values of AMT. The study reveals that the inclusion of EG and GL to the AMT drug solution with/without additives modifies the interactions of the drug molecules due to a decrease in dielectric constant of resultant mixed media.

No abstract