Abstract: Biodegradable alkyloxycarbonylmethyl or aryloxycarbonylmethyl polyaspartate and polyglutamate which can be used as a carrier for drugs which are either in the encapsulated state or are incorporated in the polymer matrix. The polypeptide thus loaded degrades enzymatically in the organ where it has been placed and thus gradually releases the drug which it contains.

Abstract: A ligand specific to a bioactive substance to be purified is fixed, through a connecting silane, to a mineral particulate carrier chosen from among SiO.sub.2, Al.sub.2 O.sub.3, ZrO.sub.2 and TiO.sub.2, the particles of the carrier being submicronic, non-porous and having a large specific surface. The carrier is contacted with an aqueous extract containing the bioactive substances, for the time required for the substance to become specifically fixed to the carrier. The carrier is then separated and the desired bioactive substance is isolated by desorption.

Abstract: The invention concerns a process for the dehydration of a colloidal dispersion of liposomes in an aqueous liquid medium, this process being aimed at extending the conservation of the liposomes and to enable their efficient use at a later date.According to this process, there is prepared a mixture of a hydrophilic compound and the liposome dispersion. This mixture is then subjected to a dehydration operation leading to the formation of liposomes in the form of a stable powder which can be stored for a long period and from which a dispersion of liposomes can be reconstituted.