Abstract: The present invention relates to a method of preparing a nucleic-acid-containing complex formulation which can be sterilized by filtration and administered intravenously to a human, and can retain stability of polynucleotides included in the nucleic-acid-containing complex formulation. The invention also relates to a method of preparing a nucleic-acid-containing complex formulation, comprising the following steps: mixing a solution comprising two separate single-stranded polynucleotides (for example, poly I and poly C) capable of forming a double strand and a solution comprising a cationic carrier or the ingredients thereof to form the cationic carrier, and performing a dispersion treatment on the mixture.

Abstract: There is provided a method of producing an emulsion by which an emulsion consisting of uniform and microfine globules can be easily obtained with a reduced energy input as compared with the conventional technology.This method of producing an emulsion comprises applying a back pressure equal to not less than 0.2% but less than 5% of the pressure acting on the point of high-pressure emulsifying action in a high-pressure emulsification zone in the course of production of an emulsion with a high-pressure emulsification equipment. The back pressure can be obtained typically by equipping an emulsification machine with a pipeline smaller in inside diameter than the discharge line of the machine.