Stability study of O/W emulsions using zeta potential

Emulsions are widely used as medicinal and cosmetic delivery systems on account of general observations that emulsified materials normally possess the properties being exhibited by its bulk components. In order to widen scope of application of the conclusions drawn, o/w emulsions covering almost all routes of administration were considered for the study. These included parenteral emulsion, oral Emulsion and topical emulsion. Zeta potential including zeta deviation and peak position, and effective particle size of the emulsions including Z-average diameter, poly dispersity index and peak position were studied using a Zeta sizer (Malvern instrument). Employing Laser Doppler Electrophoresis and dynamic light scattering technique, Zeta potential and particle size distribution of the droplet as a function of time can be determined, which was done in this paper. Zeta potential is used to study the chemistry involved in determining whether or not an emulsion will remain stable in the environment where it will be used. Hence it is very much essential. The stability of all diluted emulsions (1% v/v) of samples in milli-Q water was studied. The parameters Zeta potential, particle size and pH were measured at 1, 2, 3, 6, 8, 10, 12, 15, 20, 30, 45, 60, 75, 90 days after dilution of the emulsions by mechanical mixing. On the stability study of all these parameters it was found that topical emulsion were most stable followed by oral and parenteral.

PDF