Preparation of redispersible dry emulsions by spray drying.

Development of stable dry emulsions being able to reform the original o/w-emulsion by reconstitution in water is presented. Dry emulsions were prepared by spray drying liquid o/w-emulsions in a laboratory spray dryer. Three hydroxypropylmethylcellulose (HPMC) types were applied as solid carrier and emulsifier. The lipid phase was fractionated coconut oil. The ratio of solid carrier to lipid phase influenced the reconstitution properties. It was possible to prepare redispersible dry emulsions of a lipid content up to 40% dry powder mass. The different HPMC types had no noticeable effect on the reconstitution properties, but too viscous liquid o/w-emulsions were difficult to atomise. The type of rotary atomizer, or the rate of rotation did not affect the technical properties of the dry emulsions containing 40% lipid. It was concluded that low viscosity HPMC was a useful solid carrier. The dry emulsions remained physically stable for at least 6 months.