초록 ▼

Microspheres are prepared by a process comprising the steps of (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 mate

Microspheres are prepared by a process comprising the steps of (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 microsphere 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. Microcapsules, suitable for intra-arterial administration, being hollow and enclosing a gas- or vapor-filled space essentially without solid material therein and being capable of being dried to form a powder of such microcapsules, in which more than 30% of the microcapsules have a diameter within

1. Microcapsules, suitable for intra-arterial administration, being hollow and enclosing a gas- or vapor-filled space essentially without solid material therein and being capable of being dried to form a powder of such microcapsules, in which more than 30% of the microcapsules have a diameter within a 2 .mu.m range and at least 90% have a diameter within the range 12.0-25.0 .mu.m.