Surface and micellar properties of Chloroquine Diphosphate and its interactions with surfactants and Human Serum Albumin

This manuscript addresses the physicochemical behavior of an antimalarial drug Chloroquine Diphosphate (CLQ) as well as its interaction with anionic surfactants and Human Serum Albumin (HSA). Surface tension and specific conductivity were employed to detect the critical micelle concentration (CMC) and thus its surface and thermodynamic parameters were calculated. Solubilization of this drug within micelles of anionic surfactant sodium dodecyl sulfate (SDS) has also been studied. UV/Visible spectroscopy was used to calculate partition coefficient (Kx), free energy of partition and number of drug molecules per micelle. The complexation of drug with HSA at physiological conditions (pH 7.4) has also been analyzed by using UV/Visible and fluorescence spectroscopy. The values of drug-protein binding constant, number of binding sites and free energy of binding were calculated.

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► Free energy of adsorption is more negative than free energy of micellization.
► Shifts in UV/Visible spectra in presence of SDS indicated interaction of CLQ with SDS.
► The decrease in fluorescence intensity of HSA by CLQ shows its binding with HSA.