Patent ID: 7838644

Claim:
A process for the preparation of an epiK5-N,O-oversulfate-derivative having an iduronic acid content of 20-60%, a mean molecular weight from approximately 2,000 to approximately 45,000 and a sulfation degree of at least 4, which comprises (a) treating an epiK5-N-sulfate-derivative, in acidic form, with tertiary or quaternary organic base, letting the reaction mixture to stand for a time period of 30-60 minutes at a pH of approximately 7 and isolating its salt with said organic base; (b) treating said salt of the epiK5-N-sulfate-derivative with an O-sulfation reagent under the conditions of O-oversulfation; and (c) treating said oversulated salt with a reagent of an N-sulfation reagent and isolating the epiK5-N,O-oversulfate-derivative thus obtained.