Crystallization from microemulsions - a novle method for the preparation of new crystal forms of asparame

摘要

solubilization and crystallizaiton of he artificial sweetener aspeartame (APM), in water/isooctane microemulsions stabilized with sodium diisooctyl sulfosuccinate (AOT) has been investiated. The amount of aspparame that could be solubilized depended primarily on the amont of surfacant and on the temeprture. The maximum AOT/aspartame molar ratio at the w/o interface is shown to be k6.2 at 25 deg C. IOt was cncluded that the dipeptide is located at w/o interface inerspersed between surfactant moleuclaes and that it acts as a cosurfacant. A new crystal form., JAPM III, was obainedby cooling of hot w/isooctane/AOT microemulsions contining solubilized asppartame. The new crystal form exhibits a distinct X-ray diffraction powder pattern, as well as canges in he FTIR spectra, thermogravimetric and DSC patterns. H-NMR specra of APM III dissolved in D_2O were identical to the spectrum of commercial adpartame recorded udner the same conditons. The new crysal form has greatly improved dissolution kinetics.