Polymers with controlled physical state and bioerodibility
AssigneeAdvanced Polymer Systems, Inc.
InventorsJorge Heller, Steven Y. Ng
Life of this patent
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Abstract
Polymers useful as orthopedic implants or vehicles for the sustained delivery of pharmaceutical, cosmetic and agricultural agents are prepared in such a manner that the rate and degree to which they are hydrolyzed can be controlled without addition of exogenous acid. This control results from the incorporation of esters of short-chain .alpha.-hydroxy acids such as esters of glycolic acid, lactic acid or glycolic-co-lactic acid copolymer into the polymer chain and variation of the amount of these esters relative to the polymer as a whole.
Claims30
A polymer of Formula I ##STR23## where R* is a C.sub.1 -C.sub.4 alkyl;
- each A is selected from the group consisting of --O--R.sup.1 --, --O--R.sup.2 --, or (--O--R.sup.3).sub.q --, where q is 1 to 20;
- n is at least 5;
- and
- R.sup.1 is ##STR24## in which p is 1-10;
- R.sup.4 is hydrogen or a C.sub.1 -C.sub.6 alkyl;
- and
- R.sup.5 is ##STR25## where:
- s is 1 to 100;
- t is 1 to 12;
- R.sup.2 is ##STR26## when q is 1, R.sup.3 is ##STR27## in which:
- x is 1 to 100;
- y is 1 to 12;
- R.sup.6 and R.sup.7 are independently a C.sub.1 -C.sub.12 alkylene;
- R.sup.8 is hydrogen or a C.sub.1 -C.sub.6 alkyl;
- and
- R.sup.9 is a C.sub.1 -C.sub.6 alkyl;
- or
- R.sup.8 and R.sup.9 taken together are a C.sub.3 -C.sub.10 alkylene;
- and
- when q is 2 to 20, each R.sup.3 may be the same or different and is ##STR28## where x, y, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are as defined above, R.sup.10 is
- hydrogen or a C.sub.1 -C.sub.4 alkyl, and R.sup.11 is a C.sub.1 -C.sub.4 alkyl;
- provided that the polymer comprises at least 0.1 mole percent of units in which A is --O--R.sup.1 --.
A process for preparing a polymer of Formula I ##STR35## where R* is a C.sub.1 -C.sub.4 alkyl;
- each A is selected from the group consisting of --O--R.sup.1 --, --O--R.sup.2 --, or (--O--R.sup.3).sub.q --, where q is 1 to 20;
- n is at least 5;
- and
- R.sup.1 is ##STR36## in which:
- p is 1-10;
- R.sup.4 is hydrogen or a C.sub.1 -C.sub.6 alkyl;
- and
- R.sup.5 is ##STR37## where:
- s is 1 to 100;
- t is 1 to 12;
- R.sup.2 is ##STR38## when q is 1, R.sup.3 is ##STR39## in which:
- x is 1 to 100;
- y is 1 to 12;
- R.sup.6 and R.sup.7 are independently a C.sub.1 -C.sub.12 alkylene;
- R.sup.8 is hydrogen or a C.sub.1 -C.sub.6 alkyl;
- and
- R.sup.9 is a C.sub.1 -C.sub.6 alkyl;
- or
- R.sup.8 and R.sup.9 taken together are a C.sub.3 -C.sub.10 alkylene;
- and
- when q is 2 to 20, each R.sup.3 may be the same or different and is ##STR40## where x, y, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are as defined above, R.sup.10 is
- hydrogen or a C.sub.1 -C.sub.4 alkyl, and R.sup.11 is a C.sub.1 -C.sub.4 alkyl;
- provided that the polymer comprises at least 0.1 mole percent of units in which A is --O--R.sup.1 --;
- the process comprising reacting a diketene acetal of Formula II ##STR41## in which L is hydrogen or a C.sub.1-3 alkyl;
- with a diol of Formula III(a) or a mixture of two or more diols of Formulas III(a), III(b) or III(c):
- HO--R.sup.1 --OH III(a)
- HO--R.sup.2 --OH III(b)
- H(--O--R.sup.3).sub.q --OH III(c)
- provided that at least 0.1 mole percent of the total diol mixture is a diol of Formula III(a).
A polymer that is the product of a reaction between:
- (a) a diketene acetal of Formula II ##STR42## in which L is hydrogen or a C.sub.1-3 alkyl;
- and (b) a polyol or mixture of polyols in which at least 0.1 mole percent of the total polyol content is a diol of the formula HO--R.sup.1 --OH where R.sup.1 is ##STR43## in which:
- p is 1-10;
- R.sup.4 is hydrogen or a C.sub.1 -C.sub.6 alkyl;
- and
- R.sup.5 is ##STR44## where:
- s is 1 to 100;
- and
- t is 1 to 12.
Dependencies are inferred from the claim text.