The present invention is in the area of administration forms and delivery systems for drugs, vaccines and other biologically active agents. More specifically the invention is related to the preparation of suspensions of colloidal
solid lipid particles (SLPs) of predominantly anisometrical shape with the
lipid matrix being in a stable polymorphic modification and of suspensions of micron and submicron particles of bioactive agents (PBAs); as well as to the use of such suspensions or the lyophilizates thereof as delivery systems primarily for the parenteral administration of preferably poorly water-soluble bioactive substances, particularly drugs, and to their use in cosmetic, food and agricultural products. SLPs and PBAs are prepared by the following emulsification process: (1) A
solid lipid or bioactive agent or a mixture of
solid lipids or bioactive agents is melted. (2) Stabilizers are added either to the lipid or bioactive agent and to the aqueous phase or to the aqueous phase only depending on their physicochemical characteristics. Stabilizers may also be added or exchanged after homogenization. (3) Drugs or other bioactive substances to be incorporated into the SLPs may be melted together with the lipids if the physicochemical characteristics of the substance permit or may be dissolved, solubilized or dispersed in the lipid melt before homogenization. (4) The aqueous phase is heated to the temperature of the melt before mixing and may contain for example stabilizers, isotonicity agents, buffering substances, cryoprotectants and / or preservatives. (5) The molten lipid compounds and the bioactive agents are emulsified in an aqueous phase preferably by high-pressure homogenization.