Preparation and evaluation of w/o/w type emulsions containing vancomycin.

The objective of this contribution is to summarize the preparation and application of water-in-oil-in-water type multiple emulsions (w/o/w emulsions) entrapping vancomycin (VCM). Formulations of the emulsions (the composition of an oily phase or the type and concentrations of surfactants) and emulsification methods (a stirring method and a membrane method) or conditions (rotation rates, pore sizes of membrane or operation pressures) were evaluated in order to prepare stable w/o/w emulsions. The pharmaceutical properties of the w/o/w emulsions - particle sizes, viscosity, phase separation and drug entrapment efficiency were measured and evaluated. We prepared stable w/o/w emulsions with a particle size of about 3 micrometer and an entrapment efficiency of VCM of about 70%. When this emulsion was administered intravenously to rats, plasma concentrations of VCM were prolonged compared to the VCM solution alone. The results of this study show the potential of the w/o/w emulsions for several clinical applications as one of the drug delivery systems.