The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 16, 2001
Filed:
Aug. 17, 1999
Wilhelmus Everhardus Hennink, Waddinxveen, NL;
Okke Franssen, Utrecht, NL;
Octoplus B.V., Leiden, NL;
Abstract
A process for the preparation of a controlled release system, comprising forming of an aqueous two-phase system form at least two water soluble polymers which are incompatible in solution, at least one of these polymers being cross-linkable, the cross-linkable polymer phase being emulsified in the other polymer phase; adding at least one relesable compound which is soluble in the cross-linked polymer phase in the aqueous solution, allowing the releasable compound to diffuse in the cross linkable polymer phase; cross-linking the cross-linkable polymer before or after the releasable compound is added, preferably to a degree that the pores in the cross-liked structure are substantially smaller than the particle size of the releasable compound; and separating the cross-linked structures enclosing the release able compound from the other phase. Further, the invention relates to microspheres, at least 80 wt. % thereof having a particle size of between 100 nanometers and 1000 um, which microspheres are comprised of a degradable, cross-linked polymer encapsulating at least one releasable compound, the pore size of the cross-linked polymer being smaller than the particle size of the releasable compound.