No abstract

The micellization properties, solubilization capability, and catalytic effect of conventional nonionic surfactants and amphiphilic compounds of oligomeric (Tyloxapol) and polymeric (Synperonic F 68, Pluronic F 127) structure were compared. The systems studied demonstrate a marked catalytic effect toward basic hydrolysis of p nitrophenyl laurate, which exceeds the effect of aqueous alkali solutions by two orders of magnitude. Correlations between the solubili zation capacity of aggregates and their catalytic effect were observed. The maximum efficiency was found for the Tyloxapol solution. The synergetic enhancement of the catalytic effect was observed for the mixed Tyloxapol cetyltrimethylammonium bromide systems in the presence of small amounts of cationic surfactant.Amphiphilic compounds including surfactants and polymers are widely used in gene therapy for transporta tion of medicines and as the catalysts (nanoreactors) sim ulating the basic factors of catalytic action of enzymes. 1-4 Specific features of chemical and biochemical processes occurring in the systems based on surfactants arise from the nanoscale sizes of the reaction zone and from the devel oped area of the interface layer, which determine the be havior of reactants. 5-8 Structural variations in the sub stances forming the interface, as well as directed variation of the contributions of electrostatic, hydrophobic, and spe cific interactions between the surface and the reactants allow one to control the rates of chemical transforma tions. Mixed solutions of amphiphilic compounds are promising for controllable variation of the surface proper ties of aggregates. Previously, 9-12 we have shown that modification of micellar solutions of nonionic surfactants by ionic surfactant additives can be a tool for target con trol of the rates of ion molecular reactions due to the change in the microscopic properties of the interface, such as the surface potential, micropolarity, etc. In particular, a syn ergetic effect in the micelle forming and catalytic proper ties of the systems based on cetyltrimethylammonium bro mide (CTAB) and nonionic surfactants Triton X 100 and Brij 97 was revealed. 9 It was shown 11 that the addition of CTAB to a Triton X 100 solution results in the formation of mixed aggregates in which an increase in the rate of basic hydrolysis of carboxylic acid esters and the acids containing four coordinate phosphorus is observed.The present work is devoted to the study of aggregation of biocompatible amphiphilic nonionic compounds pos sessing the surface activity, to estimation of their solubiliza tion ability toward biologically active compounds, and to control of the reactivity of the latter. Particular attention is paid to the study of aggregation and catalytic activity of the mixed systems based on CTAB and Tyloxapol (non ionic amphiphile with oligomeric structure). Mixed sys tems based on surfactants are widely used in modern tech nologies; 13 therefore, information on the properties of such systems is topical. The mixed systems based on T...