Polymers of unsymmetrically substituted 1,4-dioxane-2,5-diones

• US 4,033,938 A
• Filed: 03/14/1975
• Issued: 07/05/1977
• Est. Priority Date: 01/21/1974
• Status: Expired due to Term

• Current Assignee: American Cyanamid Co (Pfizer Inc.)
• Original Assignee: American Cyanamid Co (Pfizer Inc.)
• Inventors: Perciaccante, Vincent Anthony, Rosensaft, Michael Norman, Augurt, Thomas Anthony
• Primary Examiner(s): Czaja, Donald E.
• Assistant Examiner(s): Nielsen, E. A.
• Application Number:
  US05/558,527
• Time in Patent Office: 844 Days
• Field of Search: 260/78.3 R, 260/340.2
• US Class Current: 528/354
• CPC Class Codes: A61L 17/105 Polyesters not covered by A61L17/12
• CPC Class Codes: C08G 63/08 Lactones or lactides

Abstract

Unsymmetrically 3,6-substituted 1,4-dioxane-2,5-diones may be polymerized to give living-tissue absorbable, hydrolytically degradable surgically useful polymers. These polymers have predominantly regular rather than random spacings of side chains, may be stereoregular and tend toward higher crystallinity than randomly sequenced polymers. A polymer of 3-methyl-1,4-dioxane-2,5-dione has the same empirical formula as an equimolecular copolymer of lactic and glycolic acid but has unique physical properties resulting from its more regular steric configuration. Polymers and copolymers of 3- and 3,6-unsymmetrically substituted 1,4-dioxane-2,5-diones have surgically useful mechanical properties. On implantation, in living mammalian tissue, the polymers are absorbed, and replaced by living tissue.

Claims

1. A method of forming a polymer containing more than 2% by weight of recurring units of the formula:

##STR19## and the remaining units are ##STR20## where R₁ and R₂ are not the same as R₃ and R₄, R₁ has at least one carbon atom, and R₁, R₂, R₃, R₄, R₅, and R₆, are separately selected from the group consisting of hydrogen and the radicals methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, and phenyl which comprises heating, in the presence of a catalyst, at least 2% by weight of an unsymmetrically substituted 1,4-dioxane-2,5-dione of the formula;

##STR21## where R₁, R₂, R₃ and R₄ are defined as above and at least one compound of the formula;

##STR22## where R₅ and R₆ are defined as above.

2. The method of claim 1 which comprises treating 3-methyl-1,4-dioxane-2,5-dione and glycolide with a tin chloride dihydrate catalyst until polymerized.

3. A polymer containing more than 2% by weight of recurring units of the formula:

##STR23## and the remaining units are ##STR24## where R₁ is CH₃ - or H-.

4. The polymer of claim 3 which has the formula:

##STR25## and n is such that the weight average molecular weight is at least about 5,000.

5. The polymer of claim 3 containing 50 or more % by weight of recurring units of the formula:

##STR26##