초록 ▼

Microspheres are prepared by a process comprising (i) spray-drying a solution or dispersion of a wall-forming material in order to obtain intermediate microspheres and (ii) reducing the water-solubility of at least the outside of the intermediate microspheres. Suitable wall-forming materials include

Microspheres are prepared by a process comprising (i) spray-drying a solution or dispersion of a wall-forming material in order to obtain intermediate microspheres and (ii) reducing the water-solubility of at least the outside of the intermediate microspheres. Suitable wall-forming materials include proteins such as albumin and gelatin. The microspheres have walls of 40-500 nm thick and are useful in ultrasonic imaging. The control of median size, size distribution and degree of insolubilisation and cross-linking of the wall-forming material allows novel microsphere preparations to be produced. In particular, the microspheres may be 15-20 .mu.m, targeted to selected areas of the body or of prolonged life in the circulation.

대표청구항 ▼

1. A process comprising the step of atomizing a solution or dispersion of an organic and biodegradable wall-forming material in a liquid carrier into a gas in order to obtain gas- or vapor-filled microcapsules by evaporation of the liquid carrier, wherein(i) the wall-forming material is selected fro

1. A process comprising the step of atomizing a solution or dispersion of an organic and biodegradable wall-forming material in a liquid carrier into a gas in order to obtain gas- or vapor-filled microcapsules by evaporation of the liquid carrier, wherein(i) the wall-forming material is selected from the group consisting of tert-butyloxycarbonylmethyl polyglutamate, polysaccharides, polylactides, polyglycolides, copolymers of polylactides and polyglycolides, copolymers of lactides and lactones, polyamino acids, polypeptides, proteins, poly(ortho)esters, polyalkylcyanoacrylates, polyamides, polyhydroxybutyrate, polydioxanone, poly-.beta.-aminoketones, polyphosphazenes and polyanhydrides; and (ii) said microcapsules comprise a block copolymer material which, following introduction into the human bloodstream, directs said microcapsules away from the reticulo-endothelial system and/or reduces opsonization of said microcapsules, such that said microcapsules have an in vivo t1/2 of at least 5 minutes in blood or in tissue perfused by the blood.