Colloidal suspension of submicronic particles for delivering active principles and method for preparing same

A suspension of submicronic particles that are stable in the absence of surfactants, wherein the particles are capable of associating in the suspension in a nondissolved state with at least one active principle such that the active principle is released in a sustained and/or delayed manner in vivo;

• wherein the suspension can be obtained spontaneously in the absence of surfactant by reacting at least one amphiphilic copolymer with a liquid that is not a solvent for hydrophilic amino acids, and
• wherein the particles being individualized supramolecular arrangements based on an amphiphilic copolymer comprising:
• at least one block of α-peptide-linked hydrophilic linear polyamino acid, wherein the hydrophilic amino acids are in an at least partially ionized form;
• and
• at least one block of at least one hydrophobic polymer comprising at least one α-hydroxycarboxylic acid polymer.

A method of preparing a suspension, wherein the method comprises:

• (i) at least one α-hydroxycarboxylic acid polymer prepared by polymerization of α-hydroxycarboxylic acid monomers and comprising at least one protected reactive group, wherein the at least one α-hydroxycarboxylic acid polymer is deprotected;
• (ii) at least partially ionizable hydrophilic amino acid that is copolymerized in the presence of at least one organic solvent;
• and
• (iii) the at least one deprotected α-hydroxycarboxylic acid polymer block of step (i) is added to the poly amino acid block polymerization medium of step (ii) before, during or after the step (ii) polymerization to form a block copolymer.