Determination of long-term stability of vitamin E emulsion and formation of microemulsions by using laser light scattering and UV absorption measurements

This paper presents methods of determining the long-term stability of vitam in E emulsion and formation of microemulsions. Several emulsion systems for med by using anionic, zwitterionic and cationic surfactants have been studi ed in the presence and absence of NaCl. Several conclusions can be drawn: ( 1) by using UV absorption and particle size measurements, one may be able t o predict the long-term stability of an emulsion or the possibility of form ing a microemulsion by measuring the initial properties of an emulsion, (2) in order to form a stable vitamin E emulsion or microemulsion, the initial properties of the emulsion should have the following features : (a) the pa rticle size is less than or equal to 200 nm, (b) the surfactant system has a saturation value 2 1 and (c) the surfactant system can dissolve a substan tial amount of vitamin E without causing an increase of the emulsion drople t size and (3) the saturation value and the stability of many vitamin E emu lsion systems can be increased by adding an optimum amount of NaCl.