Application of Surface Active Agents to Pharmaceutical Preparations. VI

Studies on the Modified Solubilization Titration. (III). Application to the Study of Nonionic Surfactants. (2)

Abstract

The modified solubilization titration, based on the theory of Winsor on solubilization, was found to be a good means for the study of solubilization system by measuring the critical temperature of solubilization. The surfactants used were 7.5, 9, and 15 moles of NP, the solubilizate was xylene, and cyclohexanol was used as the solubilization adjustor. It was thereby found that the critical temperature of solubilization at NP 9 moles was approximately intermediate of those with 7.5 and 15 moles (Figs. 1 and 5). The relationship between combination of surfactants and critical temperature of solubilization showed approximately linear change in the combination of NP-9 and 7.5 moles or NP-9 and 15 moles, but the relationship between combination and temperature was not linear in the combination of NP-7.5 and 15 moles. These results indicate that there is a difference between the HLB value calculated and the value obtained from actual emulsification or solubilization tests according to the kind of combination of surfactants and it was thought necessary to consider the foregoing relationship of curves and to bear this in mind when using the HLB system in actual practice.