FORMULATION AND EVALUATION OF O W EMULSIONS USING EXPERIMENTAL-DESIGN/

The aim of this work is to apply factorial design methods to reduce th e number and time of the various steps required to formulate and evalu ate stable emulsions. A preliminary study was performed to optimize th e most accurate operating parameters, These operating conditions were applied to the determination of the required HLB of o/w emulsion. A se cond experimental design was then applied and emulsion stability was e stimated by the average size of the droplets, the emulsion viscosity a nd the emulsion conductivity, In the case of average diameter, the bes t emulsion corresponds to the smallest particle size. For viscosity, a method is suggested to determine the required HLB. For conductivity, a graphic method was used. Experimental design allowed us to determine the required HLB with good approximation in five runs for the average diameter and viscosity studies while the conductivity study needed at least eight runs and confirmed the results obtained with the first tw o methods. (C) 1998 Elsevier Science B.V. All rights reserved.