The invention relates to novel materials based on biodegradable homopolyamino acids and which can be used for the vectorization of (an) active ingredient(s) (AI). The invention also relates to novel pharmaceutical, cosmetic, dietetic or phytosanitaty compositions based on homopolyamino acids. The invention can produce a novel polymer raw material which can be used for the vectoiization of Al that can optimally be: biocompatible, biodegradable, capable of becoming easily associated with a large number of active ingredients or solubilizing them and releasing the active ingredients in vivo. According to the present invention, which primarily relates to linear homopolyamino acids having aspartic or glutamic units and whose attachments can include hydrophobic groups having 8-30 carbon atoms. The homopolymers are amphiphilic and anionic and can easily be transformed at low cost into particles for the vectorization of active ingredients. The particles can form stable aqueous colloidal suspensions.