A case study on the partitioning of pharmaceutical compound naproxen in edible oil-water system in the presence of ionic and non-ionic surfactants

Abstract

The partitioning coefficient is a physicochemical quantity which gives important information about the distribution and efficiency of bioactive compounds in various biological systems. The present work aims at detailed investigation of the partition process of drug naproxen between edible oils (olive, sunflower, sesame) and water in the presence of two differently charged surfactants consisting of SDS (sodium dodecylsulfate), DTAB (n-dodecyltrimethylammonium bromide) and non-ionic surfactant Brij 35 (polyethylene glycol dodecyl ether). The evaluation was done at atmospheric pressure and 25.0 °C by using UV–Vis spectrometric and shake-flask techniques. In this work, all the surfactants are used in a concentration below their CMC due to the turbidity that occurs in the biphasic oil-water systems in the concentrations above their CMC. The experimental results obtained indicate that the oil-water partition coefficient (Koil/w) of naproxen reduce with rising the surfactants concentration in medium irrespective of the oil employed. Moreover, these values in the surfactant media are lower in comparison with surfactant free medium. The values of standard Gibbs free energy of the transfer (ΔGw→oil∘) calculated for all binary oil-water systems have negative sign which indicates the preference of this drug for oil phase and thus spontaneous partitioning process. The surfactant effect on the partition coefficients of drug is analyzed in terms of the intermolecular interactions such as hydrogen bonding, dispersion and electrostatic forces between the drug and the surfactant.