Acid anhydrides as rate controlling agent for the erosion of polymers which latter polymers have beneficial substances dispersed throughout their matrix or where the polymer matrix surrounds the beneficial substance
AssigneeMerck & Co., Inc.
InventorsKenneth J. Himmelstein, Takeru Higuchi
Life of this patent
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Abstract
The invention relates to the use of an acid anhydride incorporated as a latentiated catalyst in poly(ortho ester) and other polymers such that upon exposure to aqueous environments the acid anhydride generates the corresponding acid which catalyzes the matrix erosion. The releasing rate of a loaded drug substance incorporated into or surrounded by the poly(ortho ester) or other polymers can be controlled in that the drug is released as the poly(ortho ester)s or other polymer is eroded by action of the acid anhydride incorporated therein.
Claims9
A controlled release device for the delivery of drugs or other biological beneficial substances which comprises:
- (a) A poly(orthoester);
- (b) an erosion catalyzing amount up to a maximum of about 25 percent, by weight, based on (a), or at least one acid anhydride selected from the group consisting of a monobasic carboxylic anhydride, a cyclic dibasic carboxylic anhydride, and a polymeric carboxylic anhydride, incorporated within the matrix of said poly(orthoester);
- and
- (c) an effective amount up to 70 percent, by weight, based on (a) and (b), of a drug or other biological beneficial substance incorporated within or to be surrounded by the matix of said poly(orthoester),
- such that when said release device is exposed to aqueous environments, the matrix of said poly(orthoester) slowly erodes and said drug or beneficial substance is released in a controlled manner.
A controlled release device for the delivery of drug or other biological beneficial substances which comprises:
- (a) a poly(orthoester);
- (b) an erosion catalyzing amount up to a maximum of about 25 percent, by weight, based on (a), dibasic anhydride;
- and
- (c) up to 70 percent, by weight, based on (a) and (b), of a .beta.-adrenergic blocking agent.
Dependencies are inferred from the claim text.