Abstract:

Solubilization and crystn. of the artificial sweetener aspartame (APM) in water/isooctane microemulsions stabilized with sodium diisooctyl sulfosuccinate (AOT) was investigated. The amt. of aspartame that could be solubilized depended primarily on the amt. of surfactant and on the temp. The max. AOT/aspartame molar ratio at the w/o interface is shown to be 6.2 at 25°C. It was concluded that the dipeptide is located at the w/o interface interspersed between surfactant mols. and that it acts as a cosurfactant. A new crystal form, APM III, was obtained by cooling of hot w/isooctane/AOT microemulsions contg. solubilized aspartame. The new crystal form exhibits a distinct x-ray diffraction powder pattern, as well as changes in the FTIR spectra, thermogravimetric and DSC patterns. H-NMR spectra of APM III dissolved in D2O were identical to the spectrum of com. aspartame recorded under the same conditions. The new crystal form has greatly improved dissoln. kinetics. [on SciFinder(R)]