Interfacial Barriers in Interphase Transport III: Transport of Cholesterol and Other Organic Solutes into Hexadecane–Gelatin–Water Matrices

Kinetics of Compositional Ripening in Emulsions Stabilized with Nonionic Surfactants

“…It is a particular case of [2] for which B I , with B = R/D [4] and local equilibrium at the interface (c I ∼ c I,∞ ). Equation [3] has been used previously to model mass transport in emulsions (6,(11)(12)(13)(14)(15)26). A case study of interface-controlled mass-transfer kinetics is the dissolution of individual drops of pure nonpolar oils in aqueous nonionic surfactant solutions when c B /c ∞ ≈ 0 and c I,∞ /c ∞ ≈ 1, for which it was found that R decays linearly in time at a rate that is proportional to c S , the surfactant concentration available to form micelles (16,17,19).…”

“…However, a simplified solution may be found by assuming a quasi-steady behavior for the concentration of mobile oil in an aqueous environment (9). In such a case, [15] …”

“…Kinetic studies aim at determining the limiting step(s) within such mechanisms that dictate mass-transfer rates and transient behavior. Most studies have been interpreted in terms of a single ratelimiting process, either (a) the diffusion of the transferred solutes in the bulk as individual molecules (6)(7)(8)(9) or incorporated in micellar aggregates (10)(11)(12) or (b) the interfacial resistance to mass transfer, which may refer to transport across a surfactant monolayer or some other physical barrier when molecular dissolution prevails (13)(14)(15), or to the adsorption and emission of micelles that act as carriers for the transported compounds (16)(17)(18)(19)(20)(21)(22). This paper reports experimental data for the kinetics of dissolution of single drops of two alkanes (decane, squalane, and their mixtures) in aqueous solutions containing a nonionic surfactant (C 12 E 8 ) at a concentration well above the cmc.…”

Mathematical modeling of surface-active and non-surface-active drug transport in emulsion systems

“…This model was based on the drug partition coefficient between the two phases and used mass balance to determine the drug concentration in the two phases. Three other theoretical models have been developed by Goldberg et al (9), Ghanem et al (10)(11)(12), and Lostritto et al (13). These models include the effect of interfacial film characteristics on emulsion transport.…”

“…Ghanem et al (10,11) studied the effect of interfacial barriers on transport in emulsion systems. They also reported that the transport rates of diethyl phthalate and cholesterol were increased in the presence of surfactants such as sodium lauryl sulfate and dodecylpyridinium chloride and were decreased by electrolytes (12). These researchers developed a theoretical model for drug transport in emulsions, which included the effect of an adsorbed gelatin interfacial film.…”