Rheological evaluation of o/w cream bases containing polymeric emulsifier

Pemulen TR-1®, a hydrophobically modified poly(acrylic acid) copolymer, was used as a primary emulsifier in the formulation of o/w semisolid emulsion systems containing 30% w/w mineral oil. Two emulsifier concentrations (0.2 and 0.4 % w/w) were employed, combined with two manufactruing procedures : direct and indirect protocol, (dispersing the polymer into the water and oil phase, respectively). The aim of the study was to determine whether and to what extent these variations alter the structure and consistency of the creams