Equilibrium solubilization of diclofenac by aqueous solutions of the products of lanolin oxyethylenation.

Systematic research has been conducted on the products of catalytic oxyethylenation of lanolin. The level of hydrophilic-lipophilic balance HLB and the amount of oxyethylene segments nTE in homologous series of products were determined by means of the 1HNMR method. Viscosity and spectrophotometry measurements were used to determine solubilization indices n/s/, the micellar partition coefficient K(m)w, and the solubility quotient i25(r) of diclofenac in aqueous solutions of surfactants. The determination of basic viscosity values enabled identification of the solubilization site of diclofenac molecules. For the purpose of application, the relationship between the amount of oxyethylene segments nTE and K(m)w of diclofenac determined in an equilibrium system was defined.