PREPARATION OF STABLE MULTIPLE W/O/W EMULSIONS USING PLURONIC (POLOXAMER)POLY(ACRYLIC ACID) COMPLEXES

A detailed study of the interactions between poly(acrylic acid) (PAA) and a range of hydrophilic poloxamer surfactants was undertaken. This enabled us to use the most appropriate combinations of these surfactants and PAA to prepare stable multiple w/o/w emulsions. Poly(acrylic acid) as Carbopol 907 was reacted with poloxamer surfactants in the forms of Pluronic F127, P104, P103, F68, P75, and P85 at pH 2, to form Pluronic (poloxamer): PAA complexes which were then used to prepare multiple w/o/w emulsions. Two types of Pluronic:PAA complexes were derived from these interactions with different particle sizes and varying bioadhesive properties. The stability of the complexes was determined by photon correlation spectroscopy while that of the emulsions was determined using a Malvern particle sizer, over a 28-day period. Stability of the emulsions prepared with these complexes were found to be related to the particle sizes of the Pluronic (poloxamer):PAA complexes and the type of lipophilic surfactants in the oil phases, The emulsion droplet sizes were also found to be related to the Pluronic (poloxamer):PAA complex sizes. (C) 1995 Academic Press, Inc.