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Effect of Temperature, Salts and Ureas on the Association Behavior of an Amphiphilic Phenothiazine Drug Promethazine Hydrochloride
Author(s) -
Rub Malik Abdul,
Naqvi Andleeb Z.
Publication year - 2012
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-012-1328-1
Subject(s) - chemistry , phenothiazine , thiourea , promethazine , urea , critical micelle concentration , amphiphile , inorganic chemistry , micelle , ion association , nuclear chemistry , organic chemistry , ion , copolymer , aqueous solution , polymer , medicine , anesthesia , pharmacology
Association behavior of an amphiphilic phenothiazine drug promethazine hydrochloride in the presence of inorganic salts (LiCl, NaF, NaCl, NaBr, and KCl) and ureas (urea and thiourea) has been studied conductometrically at different additive concentrations (0–100 mmol kg −1 ) and temperatures (293.15–308.15 K). The critical micelle concentration (CMC) values showed an inverted U‐shaped behavior with temperature; the maximum being at 298.15 K with or without additives. The inorganic salts decreased the CMC which is explained on the basis of nature and ion size. Ureas decreased the CMC at low concentration (0.2 mmol kg −1 urea and 0.1 mmol kg −1 thiourea) but, at higher concentrations, an increase in CMC was observed with both the additives. Relevant thermodynamic parameters were also evaluated and discussed on the basis of the nature of particular types of the additives. The thermodynamic parameters suggest dehydration of the hydrophobic part of the drug at higher temperatures.