Disclosed is a process for the preparation of active substance concentrates, which is distinguished in that an active-substance-containing starting material,(i) (a) is either brought into contact with a PIT emulsion and the mixtures are heated to a temperature above the phase inversion temperature of the PIT emulsion, where they are held for a sufficient period of time, or (b) is brought into contact with an aqueous mixture of lipids and emulsifiers, which mixture is suitable for the formation of PIT emulsions, and the mixture is heated with strong shearing to a temperature above the phase inversion temperature with in-situ formation of a PIT emulsion, where the mixture is held for a sufficient period of time,(ii) the mixtures are cooled and filtered and, if appropriate,(iii) subjected to ultrafiltration and/or(iv) a further solvent extraction.
