Department of Chemistry, Aligarh Muslim University, Aligarh, UP, India.
Colloids Surf B Biointerfaces. 2012 Apr 1;92:16-24. doi: 10.1016/j.colsurfb.2011.11.002. Epub 2011 Nov 7.
The micellization behaviors of two amphiphilic drugs ((amitriptyline hydrochloride (AMT) and imipramine hydrochloride (IMP)) in presence of cationic surfactants (conventional as well as gemini) have been investigated conductometrically at four mole fractions and four temperatures. The critical micelle concentration (cmc) values come out to be lower than cmc(id) values (cmc(id) is the cmc value at ideal mixing state) indicating attractive interactions between the two components in mixed micelles. Micellar mole fractions of surfactants (X(1) and X(1)(M)), calculated by Rubingh and Motomura models, are always greater than X(1)(id) (micellar mole fraction at ideal mixing). The rigid structure of drugs decreases their contribution in mixed micelles as compared to that predicted by X(1)(id) values. Although α(1) (mole fraction of surfactant) is higher for DTAB than that of 12-4-12, the contribution of 12-4-12 is almost equal to that of DTAB. The interaction parameter (β) is negative at all temperatures and at all compositions indicating attractive interactions. Activity coefficients (f(1) and f(2)) are always less than unity suggesting nonideality in the systems. Thermodynamic parameters suggest dehydration of hydrophobic part of the drug at or above certain temperature which is different for the two drugs.
两种两亲性药物（盐酸阿米替林（AMT）和盐酸丙咪嗪（IMP））在阳离子表面活性剂（传统型和双子型）存在下的胶束化行为已通过电导率法在四个摩尔分数和四个温度下进行了研究。临界胶束浓度（cmc）值低于 cmc(id) 值（cmc(id) 是理想混合状态下的 cmc 值），表明混合胶束中两个组分之间存在吸引力相互作用。Rubingh 和 Motomura 模型计算的表面活性剂胶束摩尔分数（X(1) 和 X(1)(M)）始终大于 X(1)(id)（理想混合时的胶束摩尔分数）。与 X(1)(id) 值预测相比，药物的刚性结构降低了它们在混合胶束中的贡献。尽管 DTAB 的α(1)（表面活性剂摩尔分数）高于 12-4-12，但 12-4-12 的贡献几乎与 DTAB 相等。在所有温度和所有组成下，相互作用参数（β）均为负值，表明存在吸引力相互作用。活度系数（f(1) 和 f(2)）均小于 1，表明体系中存在非理想性。热力学参数表明，在一定温度或以上，药物的疏水分子部分发生脱水，这两种药物的情况有所不同。
