Evaluating the binding ability of promethazine hydrochloride drug with sodium dodecylsulphate/sodium lauroylsarcosinate/sodium cholate in the company of uridine biomolecules: experimental and theoretical approach

Abstract

The appraisal of drug–surfactant binding interactions is pharmacologically and pharmaceutically noteworthy. The simple model compounds of nucleic acids such as nucleic acid bases/nucleosides are key biologically active molecules useful for studying interactions of nucleic acids with other components in bio-fluids. Therefore, the binding studies of promethazine hydrochloride (PMT) drug with individual surfactants such as sodium dodecylsulphate (SDS, anionic surfactant), sodium lauroylsarcosinate (SLS, amino based-surfactant), and sodium cholate (NaC, trihydroxy bile salt), and their mixed systems (PMT + SDS/SLS/NaC) at mole fractions, α PMT = 0.02, 0.04, 0.06, and 0.08 have been accomplished in water and 0.025 mol kg−1 aqueous uridine (nucleoside) solutions at temperatures (298.15, 308.15, and 318.15) K. Thermodynamic characteristics of micellization have been obtained from the conductivity studies. Binding constants (K b, K f) and standard Gibbs free energies of binding (ΔG ο b, ΔG ο f) for pure PMT drug and its mixed systems with anionic surfactants were evaluated from UV–visible absorption and fluorescence emission studies. Further, the density functional theory (DFT) calculations for studied systems were carried out to get net stabilization energies for the drug–surfactant complexes. NBO and HOMO–LUMO analyses were also carried out in the absence/presence of uridine. Dynamic light scattering study was used to measure the hydrodynamic diameters in micellar systems. The major influences of hydrophobic–hydrophobic interactions among the hydrophobic groups and electrostatic (ionic and H-bond) interactions among the hydrophilic/ionic groups of PMT drug, SDS/SLS/NaC, and uridine have been depicted from the present investigations.