This review focuses on the self-aggregation properties of different drugs, as well as on their interaction with anionic, cationic, and gemini surfactants. The interaction of drugs with surfactants has been reviewed concerning conductivity, surface tension, viscosity, density, and UV-Vis spectrophotometric measurements, and their relation with critical micelle concentration (CMC), cloud point, and binding constant. The conductivity measurement technique is used for the micellization of ionic surfactants. Cloud point studies can be used for the non-ionic, and also for certain ionic surfactants. Usually, surface tension studies are mostly employed for non-ionic surfactants. The degree of dissociation that is determined is used to evaluate thermodynamic parameters of micellization at various temperatures. The effect of external parameters like temperature, salt, solvent, pH, etc., is discussed for thermodynamics parameters using recent experimental works on drug-surfactant interactions. Consequences of drug–surfactant interaction, condition of drugs during interaction with surfactants, and applications of drug–surfactant interaction are being generalized which reflects current and future potential uses of drug–surfactant interactions.

The conductivity, surface tension, viscosity and density of sodium dodecyl sulphate (SDS) solutions at different temperatures are precisely measured in the presence of 0.001 M isoniazid (INH) solution at concentrations ranging from 0.04 to 0.001 M. The critical micelle concentrations (CMC) are calculated. CMC decreases in the presence of INH in SDS and increases with rising temperature. Gibbs free energy change (∆G) is determined by using the dissociation constant (α) and mole fraction of CMC (XCMC) from conductivity methods. The negative and positive values of enthalpy change (∆H) and the entropy change (∆S) are observed, respectively. The maximum surface excess concentration (Γmax), the minimum area occupied by surfactant molecule (Amin) at the air–water interface, packing parameters (P), Gibb’s energy of adsorption (∆Gads), molar Gibb’s energy at CMC at maximum adsorption attained (ΔGm), surface pressure at CMC (πCMC), aggregation number (N), micellar radius (R) and pC20 are calculated from surface tension methods and apparent molar volume (Vᵩ) from density is determined. The Jones–Dole coefficient (B) and the Falkenhagen coefficient (A) are determined by viscosity study. Molecular dynamics simulation studies are also included for some systems to obtain density, viscosity, and surface tensions.