Micellar catalysis of organic reactions. 22. A comparison of the basic hydrolysis of benzodiazepinones in the presence of reactive counterion micelles and vesicles

Abstract

. Can. J. Chem. 66, 1566Chem. 66, (1988. The basic hydrolysis of diazepam and several N-alkyl nitrazepam derivatives has been studied in the presence of reactive counterion micelles of cetyltrimethylammonium hydroxide (CTAOH) and vesicles of didodecyldimethylarnmonium hydroxide (DDAOH). In both surfactants, the rate of hydrolysis of all compounds was found to be dependent on the hydroxide concentration at constant surfactant concentration and this was interpreted as evidence for initial amide hydrolysis. The hydrolysis in CTAOH was inhibited by added salts in the order Br-< NO3-< so4'-. At concentrations above 3 mM surfactant, the rate of hydrolysis of each compound was similar in CTAOH and in DDAOH. At lower concentrations of CTAOH, however, the rate of hydrolysis was significantly lower than that in DDAOH. On the basis of this evidence, it was concluded that the cmc of CTAOH was between 2-3 mM, which is in good agreement with the value of 1.8 mM obtained by Zana from conductivity measurements. For diazepam, a mechanistic change is indicated on transfer from water to either micelles or vesicles and since vesicles are considered good models of biological membranes, this suggests that conclusions concerning the bioavailability of diazepam should not be based on studies in water but rather on studies in either micelles or vesicles. puisque les vCsicules sont considCrCes comme de bons modeles des membranes biologiques, il est suggCrC que les conclusions concernant la bio-disponibilitk du diazepam ne devraient pas 6tre basCes sur des Ctudes dans l'eau mais plutbt sur des Ctudes dans des micelles ou dans des v6sicules.[Traduit par la revue]

Effect of alkyl chain length, head group and nature of the surfactant on the hydrolysis of 1,3-benzoxazine-2,4-dione and its derivatives

“…There are several reports on the hydrolysis of drugs in presence of micelles in which various types of surfactants behave differently [24][25][26][27][28][29]. In most of the studies work is carried out on the effect of simple drugs only and not on their derivatives.…”

“…The effects of micelles on the alkaline hydrolysis of various drugs have been studied by various workers [24][25][26][27][28][29]. Recently, we have studied the effect of cationic and anionic surfactants on the hydrolysis of isatin and its derivatives with varying hydrophobicity [30].…”

Membrane adsorption or penetration differentially modulates β-galactosidase activity against soluble substrates

“…The reactions occurring at interfaces may change their mechanism respect to the ones taking place in the bulk of a solution, with a consequent modification of the values of activation energy [23]. Contrary to what would have been expected in the case that the hydrolysis of ONPG was non-enzymatically catalyzed by its partitioning within the environment of the lipid-water interface, the A 420 did not increase in the presence of PC, indicating the absence of ONP production (Fig.…”

Self-Assembly of Didodecyldimethylammonium Surfactants Modulated by Multivalent, Hydrolyzable Counterions

“…Apart from fundamental interest, DDA + surfactants have commercial, chemical, and pharmaceutical applications − and are implicated in biological self-assembly. , Much attention has been focused on DDA + bromide, Br – counterion (DDAB), − an insoluble surfactant that swells in water to form two L α phases . In dilute solutions (< 3 wt %), a biphasic solution consisting of swollen lamellar crystallites dispersed in a metastable sponge phase, L 3 , forms, which eventually becomes an isotropic micellar solution …”