Method of making free acids from polysaccharide salts
US5789571A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 15, 1997 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Jan 15, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07H7/033
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A free acid form of a polysaccharide is produced from its alkali-metal salt. In one example, free-form hyaluronic acid is produced by preparing a solution of an alkali-metal salt of hyaluronic acid, dispersing into the solution a strong acid, enclosing the dispersion within a semi-permeable membrane, dialyzing the dispersion in water, and harvesting the product from within the membrane. The strong acid can be hydrochloric acid, sulfuric acid, nitric acid, orthophosphoric acid, or oxalic acid, for example. The semi-permeable membrane has a molecular weight cut-off large enough to pass the strong acid, and preferably much larger. The invention provides a simple and economical way to produce a product which is not commercially available.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.