A novel method for rapid non destructive determination of o/w creams stability

A nonconventional method for evaluation of emulsion stability was developed. The method was found to be valid for viscous emulsions and results obtained are in good correlation to conventional methods compared. The technique is based on electrical conductivity measurements during nondestructive short heating-cooling-heating cycles carried out on cosmetic viscous emulsions. Conductivity curves were obtained on a recorder, where the second heating cycles were lower and almost parallel to the first heating curves. The bigger the conductivity differences between the two heating curves, the lower is the emulsion stability. A relative Stability Index Δh, indicating relative change in conductivity between two cycles was elaborated. This index was usefull in finding out - optimal required HLB values for required emulsion - optimal amount of oily phase - emulsifier concentration.