Effect of additives on the aggregation phenomena of amphiphilic drug and hydrotrope mixtures

Association behavior between the cationic antidepressant drug imipramine hydrochloride (IPH) and anionic hydrotrope - sodium benzoate (NaBez) mixtures in aqueous solutions, along with the electrolytes NaCl (50 mmol.kg(-1)) and NaBr (50 mmol.kg(-1)) were studied using a conductometric technique at four different temperatures. The results showed a decrease in critical micelle concentration (cmc) of IPH (drug) in combination with NaBez, viewing a remarkable interaction amongst studied constituents along with cmc values of IPH drug further lessens through raised in mole fraction (alpha 1) of NaBez. The electrolytes NaCl and NaBr reduced the cmc of IPH, NaBez together with their mixture (IPH-NaBez) in diverse ratio and NaBr was additionally effectual in reducing the cmc of the system in comparison to NaCl. Moreover, the cmc values of IPH and NaBez mixtures showed a lower than ideal cmc (cmc(id)) value characterizing the non-ideality in system. Additional parameters of the conductometric method such as the micellar mole fraction employing the Rubingh and Rodenas models, interaction parameter (beta), activity coefficients of the mixed micelles, and excess Gibbs free energy using the Rubingh and Rodenas models and so on were evaluated. The activity coefficients values were lessened in electrolyte solvent in the entire systems showing the enhanced non-ideality of mixed system in electrolyte solution. At various temperatures, thermodynamic parameters were also evaluated in aqueous along with electrolyte solutions. The interactions amongst the studied constituents in the aqueous system were also evaluated by fluorescence and FT-IR studies and explored in detail. (C) 2018 Elsevier B.V. All rights reserved.