Preparation of diagnostic agents
AssigneeAndaris Limited
InventorsAndrew D. Sutton, Richard A. Johnson, Peter J. Senior, David Heath
Life of this patent
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Abstract
Microcapsules 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 microcapsules and (ii) reducing the water-solubility of at least the outside of the intermediate microcapsules. Suitable wall-forming materials include proteins such as albumin and gelatin. The microcapsules have walls of 40-500 nm thick and are useful in ultrasonic imaging. The control of median size, size distribution and degree of insolubilization and cross-linking of the wall-forming material allows novel microsphere preparations to be produced.
Claims6
A process of forming a stable, sterile powder comprising hollow microcapsules which are suspendable in a medium suitable for parenteral administration to form a suspension suitable for ultrasound imaging when administered parenterally, said process comprising:
- a) providing a solution of a protein selected from the group consisting of collagen, gelatin and serum albumin in a liquid;
- b) atomizing said solution through an orifice into a heated gas such that said liquid evaporates thereby forming hollow microcapsules of said protein having a diameter of from 0.05 to 20 .mu.m;
- c) heating said microcapsules to reduce the water-solubility of said protein thereby obtaining said microcapsules as a stable powder;
- and
- d) rendering said powder sterile.
Dependencies are inferred from the claim text.