US4983745A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Meso-lactide, processes for preparing it and polymers and copolymers produced therefrom
Assignee: Boehringer Ingelheim GmbH
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Filing: 1989-04-03
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Granted: 1991-01-08
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Expires: 2009-04-03
Abstract
Abstract The invention relates to a meso-lactide having a melting point of 52.8 DEG C., processes for its preparation, and its use in the preparation of resorbable polymers and copolymers.
Inventors
- 👤 Manfred Muller
- 👤 Joachim Hess
- 👤 Wilhem-Gustav Schnell
- 👤 Dieter Bendix
- 👤 Gunther Entenmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:56
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/64; A; A61; A61K; A61K47/00; A61K47/30; A61K47/34; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/64; A61L17/00; A61L17/06; A61L17/10; A61L17/12; A61L27/00; A61L27/14; A61L27/18; A61L31/00; A61L31/04; A61L31/06; C07; C07D; C07D319/00; C07D319/10; C07D319/12; C08G63/02; C08G63/06; C08G63/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
63 words
Process for preparing meso-lactide, characterised in that racemic polylactic acid is depolymerised in the presence of tin, tin salts or organic tin compounds as catalyst, the lactide formed is recrystallised in order to separate off a quantity of D,L-lactide, the mother liquor remaining is concentrated by evaporation and the residue is rectified, the first distillate obtained being the meso-lactide, which optionally is recrystallised.
Claim 2
Dependent Claim
63 words
Process for preparing meso-lactide, characterised in that racemic polylactic acid is depolymerised in the presence of tin, tin salts or organic tin compounds as catalyst, the lactide formed is recrystallised in order to separate off a quantity of D,L-lactide, the mother liquor remaining is concentrated by evaporation and the residue is rectified, the first distillate obtained being the meso-lactide, which optionally is recrystallised.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |