Influences of short-chain alcohols, urea and temperature on aggregation behaviour of tetradecyltrimethylammonium bromide and antidiabetic drug mixture

Abstract

In this investigation, the supramolecular interaction between a surfactant- tetradecyltrimethylammonium bromide (TTAB) and an antidiabetic drug metformin hydrochloride (MNH) was studied in the presence of some additives (alcohols/urea). The conductometric analysis as a function of surfactant concentration was used to assess the critical micelle concentration (CMC) of TTAB + MNH mixed system. The effect of a gradual change of temperature on CMC within a certain range (298.15–318.15 K) was monitored to assess the thermodynamic nature of micellisation process. In addition, estimation of thermodynamic parameters (ΔGmo, ΔHmo, and ΔSmo) and the determination of the degree of counter ion binding (β) give insight into the relative viability of a micellisation process. The values of ΔGmo were negative in all the mixed solvents studied and this was dependent on the chain length of the used alcohols. The thermodynamic parameters of transfer for shifting the micelles from aq. medium to aq. alcohols media and enthalpy-entropy compensation were also computed, compared with literature values and discussed with appropriate reasoning. Several supramolecular forces, including H-bonds, dipole–dipole, ion-dipole, hydrophobic, and electrostatic interactions, were recommended for the aggregation of the TTAB + MNH system.