The present invention relates to novel biodegradable materials based on modifiedpolyamino acids that can be used, in particular, for the vectorization of activeprinciple(s) (PA). The invention also relates to novel pharmaceutical, cosmetic,dietetic or phytosanitary compositions based on these polyamino acids. Theobjective of the invention is to provide a novel polymer starting material thatis capable of being used for the AP vectorization and that makes it possible tooptimally satisfy all the specifications required in the case in point: biocompatibility,biodegradability, ability to associate easily with numerous active principlesor to dissolve them, and to release these active principles . Thisobjective is achieved by the present invention, which relates to novel polyglutamatesmodified by cationic groups that, if they can be deprotonated, have a pKa greaterthan or equal to 7, and by hydrophobic groups comprising from 8 to 30 carbon atoms.These polyglutamates modified by cationic groups are capable of being easilyand economically converted into particles for the vectorization of active principles,these particles being themselves capable of forming stable aqueous colloidalsuspensions. These modified polyglutamates have the advantage of being lessviscous than other similar polymers, while retaining an ability to associateproteins such as insulin. Some are soluble in water at acid pH and become insolubleat physiological pH (7.4) and should therefore, during a subcutaneous injection,precipitate at the injection site.
