Mixed micellization study of ibuprofen (sodium salt) and cationic surfactant (conventional as well as gemini)

Herein, we have studied the interaction between cationic surfactant (conventional [myristyltrimethylammonium bromide, MTAB] as well as gemini surfactant 1, 4-butanediyl-α, ω-bis(dimethyltetradecylammonium bromide) (14-4-14)) and anti-inflammatory sodium salt of ibuprofen (IBU) drug in aqueous solutions by using tensiometry method at 298.15 K. The means of the interaction of drugs by added foreign materials is of paramount importance in the drug delivery. Ibuprofen is used for the relief of pain, fever, and swelling. From this study we have evaluated different parameters, for example, critical micelle concentration (cmc), micellar mole fraction of mixed micelles/mixed interface (X1m/X1σ), micellar/surface interaction parameter (βm/βσ), activity coefficients (f1m/f1σ and f2m/f2σ) of the mixed micelles/mixed interface, excess Gibbs free energy of mixed monolayer/mixed micelle formation ((X1m) / (X1σ)), surface excess concentration (Γmax) etc. and discussed in detail. The micellar interaction parameter (βm) was determined from the critical micelle concentration values of the pure surfactant (MTAB/14-4-14) and IBU (cmc1 and cmc2) and the mixed system (cmc) using the Rubingh's model. In addition to this, various other parameters such as packing parameters of amphiphiles in the micelles (P), volume contribution of the hydrophobic chain (V0), and its effective length (lc), have also been calculated. The value of micellar mole fraction (X1m) is found to be more for IBU + 14-4-14 mixtures as compared to IBU + MTAB mixtures at lower mole fraction and vice versa at a higher mole fraction of surfactant. The ΔGom and ΔGoads values for all studied systems were found out to be negative, ie, micellization, as well as adsorption processes, are found to be energetically favorable.