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In order to explore their applications as drug delivery vehicles, the mixed interfacial/micellar behaviour of a number of dimeric surfactants (zwitterionic, cocogem and anionic) with an amphiphilic antidepressant drug imipramine hydrochloride (IMP) in aqueous solutions has been investigated. The cmc values of mixed surfactants, estimated from surface tension measurements, decrease with mole fraction (α) and tail length of the surfactants. The values in most of the cases are lower than cmcid. This indicates that mixed micelles are formed due to attractive interactions among the components. A number of simple models (those of Rosen, Rubingh, Motomura) that combine pseudophase approximation with the regular solution theory, have been used to estimate some important physicochemical parameters needed for such applications (like compositions of mixed monolayers (Xs)/mixed micelles (Xm) and the interaction parameters (β)). The values of the micellar interaction parameter (βm) come out to be negative with the magnitude order being: anionic dimerics > zwitterionic dimerics > cocogems. This is explained in light of the different structures of surfactants; IMP is positively charged and with anionic surfactants it experiences stronger attractive interactions while with cocogems its interactions are weak. With zwitterionic dimerics, the drug experiences intermediate interactions.

The effect of cationic conventional surfactants myristyltrimethylammonium bromide (TTAB),cetyltrimethylammonium bromide (CTAB), and cetylpyridinium chloride (CPC) on the interaction ofdipeptide glycyl-alanine (Gly-Ala) with ninhydrin has been studied spectrophotometrically underdifferent conditions. The reaction rates are higher in the presence of surfactants but the reaction orderremains the same in both the media (first- and fractional-order with respect to [Gly-Ala] and[ninhydrin]). Quantitative kinetic analyses of kψ[surfactant] data were performed on the basis ofpseudo-phase model of the micelles (proposed by Menger and Portnoy and developed by Bunton andRomsted) and Piszkiewicz model wherein the micellar binding constants KS for Gly-Ala and KN forninhydrin with surfactant micelles were evaluated. The catalytic efficiency in TTAB increased byadded electrolytes which had been discussed in detail., European Chemical Bulletin, Vol 3, No 2 (2014): European Chemical Bulletin

Die Geschwindigkeit der Disproportionierung von U(V) in U(VI) und U(IV) in 0.4 M NazSOrLosung wird in Abhangigkeit vom pH bestimmt.