title: Effect of electrolytes on the cloud point of chlorpromazine hydrochloride solutions.
abstract: Cloud point (CP) phenomenon occurring in amphiphilic drug chlorpromazine hydrochloride (CPZ) solutions with and without salts is reported herein. The CP of a 50mM CPZ solution (prepared in 10mM sodium phosphate, SP, buffer) was found to decrease with increasing pH, both in the absence as well as presence (50mM) of added salts (NaCl, NaBr, LiBr, KBr, tetra-n-butylammonium bromide). Whereas, at a fixed concentration of NaCl, the CP increased with increasing CPZ concentration, addition of increasing amounts of salts (NaF, NaCl, NaBr, LiCl, KCl) to 50 mM CPZ solution (at pH 6.7) caused continuous increase in CP. On the basis of these studies the binding-effect orders of counterions and co-ions have been deduced, respectively, as: Br(-) > Cl(-) > F(-) and Li+ >Na+ >K+. The similar trend of increasing CP with addition of increasing amounts of quaternary bromides (tetramethylammonium bromide, TMeAB; tetraethylammonium bromide, TEtAB; tetra-n-propylammonium bromide, TPrAB; tetra-n-butylammonium bromide, TBuAB; tetra-n-pentylammonium bromide, TPeAB) to 50 mM CPZ solutions (at pH 6.7) was found to be dependent upon the alkyl chain length of the particular salt. The overall behaviour has been discussed in terms of electrostatic interactions, micellar growth, and mixed micelle formation.
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India.
authors.forename: Sayem
authors.initials: S
authors.lastname: Alam
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Kumar
authors.forename: Andleeb Z
authors.initials: AZ
authors.lastname: Naqvi
authors.lastname: Kabir-Ud-Din
mesh_terms: D002746:Chlorpromazine / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019999:Pharmaceutical Solutions / Q000737:chemistry*; D012995:Solubility
chemical_list: D004573:Electrolytes; D019999:Pharmaceutical Solutions; D002746:Chlorpromazine