Low generational(G0–G2,G for generation) polyamidoamine(PAMAM) dendrimers were investigated as enhancers to improve the aqueous solubility of folic acid at pH 11 and pH 5.In these two cases,the solubility of folic acid increases with both the dendrimer concentration and generation.However,the solubilization mechanism is different.The electrostatic interaction between the primary amines of dendrimers and the ionized carboxylic groups of folic acid dominates the dissolution process at pH 11 while the increase of the solubility of folic acid at pH 5 is attributed to the hydrophobic encapsulation inside the dendrimer molecules.In addition,for comparison ethylenediamine was used as a small molecule control to examine the ‘‘dendritic effect'' in the dendrimer-related solubilization process.Interestingly,PAMAM dendrimers exhibit,at pH 5,a significant superiority over ethylenediamine in enhancing solubility,whereas this ‘‘dendritic effect'' cannot be observed under the basic condition.
聚酰胺胺(PAMAM)树形分子因其具有多分支对称性、内部含有大小不一的空腔以及多官能团表面等一系列结构特性,在分析化学、催化剂、涂料和薄膜技术、生物医学等领域有广泛的应用前景.本文以二乙醇胺为核,采用单边发散法合成了0.5至2代的PAMAM树形分子,并对所合成的树形分子进行了1 H NMR和FT-IR结构表征.