Improving the solubility of acipimox by cosolvents and the study of thermodynamic properties on solvation process
Danfeng Shao, Zehui Yang, Guoquan Zhou, Jingjing Chen, Shiyun Zheng, Xin Lv, Rongrong Li
文献索引：10.1016/j.molliq.2018.04.009
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摘要
For the solubility of poorly soluble acipimox to be improved, study on cosolvent selection has often been shown to be advantageous. The solubility values of acipimox in four important solvents for pharmaceuticals investigations: water, methanol, acetone, acetonitrile and their aqueous solutions have been measured at atmospheric pressure using isothermal saturation method at temperatures ranging from 283.15 to 318.15 K, ΔT = 5 K and in the mass concentration range from 0 to 1. The result showed that the solubility increased to a maximum value (at 80% mass fraction in methanol aqueous solution and acetone aqueous solution, while 60% for acetonitrile aqueous solution) and then decreased with further increase of cosolvent mass concentration. The maximum mole fraction solubility of acipimox was observed in acetonitrile aqueous (1.687 × 10−2 at 318.15 K), followed by that in acetone aqueous (1.258 × 10−2 at 318.15 K), methanol aqueous (8.370 × 10−3 at 318.15 K), The Jouyban-Acree model, van't Hoff-Jouyban-Acree model, Apelblat-Jouyban-Acree model and Ma model were applied to simulate acipimox solubility in the binary mixture compositions at various temperatures. The relative average deviation (RAD) was used as an accuracy criterion. The obtained overall RAD for back-calculated of acipimox in studied mixtures varied from 1.24% to 4.07%. Apparent thermodynamic analysis indicated that the dissolution was an endothermic, spontaneous and entropy driven process. Understanding acipimox solubility and thermodynamic properties is an important aspect of drug development. In particular, the solubility data of acipimox obtained has a major effect on its purification, recrystallization and formulation development in industrial.