Impact of numerous media on association, interfacial, and thermodynamic properties of promethazine hydrochloride (PMT) + benzethonium chloride (BTC) mixture of various composition

Herein, the impact of numerous media of fixed concentration (H2O, NaCl (50 mmol·kg−1), urea (U, 300 mmol·kg−1) and thiourea (TU, 300 mmol·kg−1)) on the association, interfacial, and thermodynamic properties of promethazine hydrochloride (PMT) and benzethonium chloride (BTC, cationic antimicrobial surfactant)) mixture in several compositions were examined via tensiometry method at room temperature (298.15 K). Along with tensiometry, the interaction between PMT and BTC was also assessed by applying the UV–visible as well as FTIR spectroscopy in an aqueous solution. PMT is used for the symptomatic relief of various allergic conditions. The employed systems critical micelle concentrations (cmc) value was acquired much lower than their calculated corresponding ideal cmc value (cmcid) owing to the interaction between components (PMT and BTC) and the interaction amongst PMT and BTC further increases through increase in mole fraction (α1) of first component (BTC). Diverse solution and surface parameters, thermodynamic parameters, etc. have been processed by use of several purported theoretical models. In NaCl media, the cmc value of singular along with mixed species (PMT + BTC) of each composition were found fewer in magnitude than aqueous media while magnitude increased in U/TU media and TU is more valuable in boosting the cmc than U. Activity coefficient value in each case was continuously found below one due to attractive interaction amongst PMT and BTC. The attained Γmax and Amin value of PMT + BTC implies that the formed mixed interface is the closer packing of PMT and BTC. Excess free energy (ΔGex) was attained negative, exhibiting that the mixed micellar/mixed monolayer stability was higher with the singular component's micelles/monolayer. The shift in frequency of pure component were attained by FT-IR study by addition of other component that also signifies the straightforward interaction among ingredients. Existing research outcomes revealed a straightforward methodology to design the employed surfactant as an efficient ingredient as a drug delivery vehicle for phenothiazine drug.