Effect of phospholipid emulsifiers on physicochemical properties of intravenous fat emulsions and/or drug carrier emulsions.

The physicochemical properties of soy bean oil emulsions stabilized with purified egg lecithins (phosphatides) of various concentrations have been examined. The zeta potential of the emulsion droplets and the mean particle size of oil droplets in 10% (w/w) o/w-type emulsion decreased with increasing emulsifier concentration and then levelled off at more than 1.2% (w/w). In rheological measurements, at the initial stage, the viscosity of 10% (w/w) o/w-type emulsion gradually increased with increasing purified egg lecithin concentration, at the next stage, a plateau was reached at about 1.0-1.4% (w/w), and at the final stage, the viscosity curve showed a dramatic increase. These results indicate that emulsions stabilized by purified egg lecithin at more than 1.2% (w/w) are likely to be sufficiently stable.