Niosomes (nonionic surfactant-based vesicles) containing rifampicin were prepared using various nonionic surfactants of sorbitan ester class and cholesterol in 50:50 percent mol fraction ratio. The drug-entrapped vesicles were characterized for their shape, size, drug entrapment efficiency and in vitro release rate. On the basis of in vitro characterization, the niosomes showing maximum entrapm...

A simultaneous determination of cationic and nonionic surfactants has been developed using ion-association titration. Tetrabromophenolphthalein ethyl ester (TBPE) was used as an indicator. Benzalkonium reacted with TBPE to form a blue ion-associate in the organic phase. When tetrakis(4-fluorophenyl)borate was added dropwise to the solution, the color of the organic phase turned to yellow at the...

Synergy and antagonism between sugar-based surfactants, a group of environmentally benign surfactants, and cationic surfactants and nonionic ethoxylated surfactants have been investigated in this study with solids which adsorbs only one or other when presented alone. Sugar-based n-dodecyl-β-D-maltoside (DM) does not adsorb on silica by itself. However, in mixtures with cationic dodecyltrimethyl...

value for the enthalpy of adsorption of both CO and NO. A plausible explanation of the correlation observed is as follows. The standard entropy of adsorption is ascribable to the stretch of the cation-carbon (or cation-nitrogen) bond and to two bending modes of CO (or NO). The frequencies involved are usually (see, e.g., ref 19) assumed to parallel the strength of adsorption AaH. As a matter of...

Iopamidol, a nonionic, water-soluble contrast medium, has been recently recommended for myelography. As with other such media, the extent of parenchymal penetration is of interest in relation to the genesis of clinical complications. In this study the degree and depth of brain penetration of intrathecal iopamidol, using an iodine concentration of 280 mg l/ml, were compared at 15 and 60 min in a...

The focus of this work is on aggregation and micellization in a lattice model for nonionic surfactants. Formation of micellar aggregates as a function of temperature and surfactant chemical potential was studied by histogram reweighting grand canonical Monte Carlo simulations. Two di erent sets of site-site interactions were utilized. The critical micellar concentration (CMC) was determined fro...

Structure of nonionic surfactant diglycerol monomyristate (C14G2) micelles in cyclohexane has been investigated by small-angle X-ray scattering (SAXS) technique. Structural modulation of reverse micelle (RM) has been systematically studied by changing composition, temperature change and added-water. The SAXS data were evaluated by the generalized indirect Fourier transformation (GIFT) method, w...

Surfactant-enhanced remediation technology has shown promising potential for removing residual organics from contaminated soils and groundwater. Using a homologous series of cationic surfactants, alkylpyridinium bromide, it was found that the molar solubilization ratio (MSR) for naphthalene decreases with decreasing carbon number in the hydrophobic tail. In contrast, with nonylphenyl ethoxylate...

The structure of micelles formed by nonionic polyoxyethylene alkyl ether nonionic surfactants, C n E m , in the room-temperature ionic liquid, ethylammonium nitrate (EAN), has been determined by small-angle neutron scattering (SANS) as a function of alkyl and ethoxy chain length, concentration, and temperature. Micelles are found to form for all alkyl chains from dodecyl through to octadecyl. D...