Physicochemical Studies on Microemulsions. 6. Phase Behavior, Dynamics of Percolation, and Energetics of Droplet Clustering in Water/AOT/n-Heptane System Influenced by Additives (Sodium Cholate and Sodium Salicylate)

Abstract

The phase behavior as well as the volume- and temperature-induced percolation of a water in oil (w/o) microemulsion system of water/AOT/n-heptane have been studied in detail in the absence and presence of additives, sodium cholate (NaC) and sodium salicylate (NaS). The results have been examined in light of the appropriate scaling equations. The scaling parameters have been observed to be not in agreement with the predicted values. The energetics of droplet clustering leading to percolation have been also estimated. The amphiphile-coated size of the water nanodroplets and their diffusion coefficient and polydispersity have been estimated in the pre- and postpercolation stages. Rationalization of the results has been attempted.

Physicochemical Investigations of Microemulsification of Coconut Oil and Water Using Polyoxyethylene 2-Cetyl Ether (Brij 52) and Isopropanol or Ethanol

“…The measurements were duplicated for checking reproducibility. The measurement procedure was similar to that presented in recent reports (13)(14)(15).…”

Formulation and Physicochemical Characterization of Microemulsion System Using Isopropyl Myristate, Medium-Chain Glyceride, Polysorbate 80 and Water

“…The mean hydrodynamic diameter of the droplets (d h ), the ploy dispersity index (PDI) and the diffusion coefficient (D) of the dispersed droplets were obtained with the aid of instrument's software as reported earlier. 18,19) Calorimetric Measurements The heats of dissolution of water in surfactant/oil system as well as of oil in surfactant/water system were measured in a TRONAC 458 Isoperibol titration calorimeter, U.S.A. using the method described earlier. 20) The mixture of IPM, polysorbate 80 and MDG or water, polysorbate 80 and MDG were taken in calorimetric vessel maintained at a constant temperature 303Ϯ0.002 K. The solution was titrated with water or oil under stirring condition up to the point of phase separation known from the phase diagram after temperature equilibration leading to the final compositions of 75/17/8, 68/17/15, 50/19/31, 22/23/55, 14/21/65 and 7/18/75 as (IPMϩMDG)/polysorbate 80/water.…”

Influence of Lipid Composition, pH, and Temperature on Physicochemical Properties of Liposomes with Curcumin as Model Drug

“…However, further studies are warranted to confirm this. Above the transition temperature, size increases, which were mostly irreversible, occurred because of the increase in liposome volume, which is common for any dispersion 43 . Because of similarities in the hydrocarbon chains 11 except for SPC, the dependence of size variation on temperature was similar for all liposomes.…”