# US 5,700,471 A · Production of fine particle dye or drug preparations

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- Number: US 5,700,471 A
- Document ID: US5700471A
- Status: Granted
- Kind: A
- Application number: 08/573,876
- Filed: 1995-12-18
- Granted: 1997-12-23
- Earliest claimed: 1993-09-01
- Assignees: BASF SE
- Inventors: Lutz End; Dieter Horn; Erik Lueddecke
- Web page: https://patentgrep.com/patent/US5700471A

## CPC

- C09B 67/0095: {Process features in the making of granulates}
- A61K 9/14: Particulate form, e.g. powders, {Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles (microspheres A61K9/16; microcapsules A61K9/50; nanocapsules, nanoparticles of the matrix type A61K9/51)}
- A61K 9/1694: {resulting in granules or microspheres of the matrix type containing more than 5% of excipient}
- B01J 13/0004: {Preparation of sols (by physical processes B01J13/0086, aerosols B01J13/0095)}
- C09B 61/00: Dyes of natural origin prepared from natural sources {, e.g. vegetable sources}
- C09B 67/0091: {Process features in the making of dispersions, e.g. ultrasonics}
- C09K 23/00: Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
- C09B: ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES {, e.g. PIGMENTS}; MORDANTS; LAKES (fermentation or enzyme using processes to synthesise a desired chemical compound C12P)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

Process for the production of fine-particle, essentially amorphous dye or drug preparations by converting a relatively coarse-particle dispersion or a solution into a colloidal dispersion in water, where the colloidal dispersion is generated at a temperature above the melting point of the dye or drug by admixing appropriately hot water (where appropriate under pressure) or an aqueous protective colloid solution so that an emulsion of a melt in aqueous medium is produced and is immediately spray-dried or converted by cooling into a suspension.

## Claims

### Claim 1

A process for producing fine-particle, essentially amorphous dye or drug preparations by converting a relatively coarse-particle aqueous dispersion or an organic solution in a solvent dissolving to an extent of at least 10% in water into a colloidal dispersion in water, wherein the aqueous dispersion or organic solution of the dye or drug is subjected to turbulent mixing at a temperature above the melting point of the dye or drug, where appropriate under pressure, with water or an aqueous protective colloid solution, and the resulting melt emulsion is immediately spray-dried or converted into a suspension by cooling.

### Claim 2 (depends on 1)

A process as claimed in claim 1, wherein no organic solvent is used.

### Claim 3 (depends on 1)

A process as claimed in claim 1, wherein the cooling takes place as quickly as possible after the formation of the hot melt emulsion.

### Claim 4 (depends on 1)

A process as claimed in claim 1, wherein water or water/solvent mixture is removed from the resulting suspension to afford an easily redispersable powder.