Abstract

W. M. Wan Rusmawati¹, F. B. H. Ahmad¹, K. Anuar² and S.Hamdan²

Phase diagrams of methyl acetate/Brij 30/H2O and methyl acetate / Tween 80 / H2O system were constructed at 25.0 ± 0.5°C. Phase diagram of Tween 80 / Brij 30 / H2O were also constructed to determine the solubility of the surfactants (Tween 80 and Brij 30) in water (aqueous solvent) at 25.0 ± 0.5°C. Ternary phase diagram of methylacetate / Tween 80:Brij 30 (80:20, and 60:40) / H2O was than constructed by incorporating methyl acetate in Tween 80 / Brij 30 / H2O system at the same temperature. The ratio at 80:20 and 60:40 of Tween 80 and Brij 30 were selected due to the different solubility points of the surfactants in water. The result showed that the mixed surfactants phase diagrams of methyl acetate/ Tween 80;Brij 30 (80:20, and 60:40)/H2O gave better performance as compared to the individual surfactant phase diagram of methyl acetate/Tween 80 / H2O and methyl acetate/Brij 30/H2O systems respectively. The isotropic region of mixed surfactants system was larger then the individual surfactant system. The higher percent of Tween 80 in methyl acetate/Tween 80:Brij 30 (80:20) / H2O system gave larger isotropic region as compared to methyl acetate/Tween 80:Brij 30 (60:40) / H2O system. Solublity of betulinic acid in fiese isotropic regions incresed with the increment of percentage of methyl acetate. In contrast, solubility of betulinic acid in isotropic region decreased with the Increments of percentage of Tween 80. However, the solubility increases with the increase of mixed surfactant Tween 80 and Brij 30.

Solublity betulinic; Isotropic; Increments

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