Method for preparing vesicular nanocapsules

Process for the preparation of nanocapsules which are vesicles of an average size of less than 1000 nm and which comprise at least one active constituent within an envelope comprising at least one polymer, comprising the steps of:

• a) obtaining at least three liquids, S1, S2 and S3, wherein S1 is an organic solvent or dispersant at least partially miscible with S2 and S3, and which is a solvent or dispersant for the at least one polymer and the at least one active constituent, S2 is a non-solvent for the at least one polymer and is not miscible with S3, and S3 is a non-solvent for the at least one polymer and a solvent or dispersant of the at least one active constituent;
• b) producing a first homogeneous liquid phase I comprising a solution of S3, the at least one active constituent and the at least one polymer in S1, S1 being brought into phase I by means of a solution of S2 in S1;
• c) preparing a second homogeneous liquid phase II comprising solvent S2 and optionally including S1 emulsified therein;
• d) mixing together liquid phases I and II;
• e) forming an emulsion of liquid phase I in liquid phase II;
• f) adding S2 to the emulsion to form in homogeneous phase II conditions in which S1 is at least partially miscible with S2, and S1 diffuses from phase I to phase II, to obtain thereby the nanocapsules in a new continuous phase III;
• and
• g) optionally eliminating at least part of S1, S2 or both S1 and S2.