Biodegradable polymer matrices for sustained delivery of local anesthetic agents
First Claim
1. A method for prolonged nerve blockade, local numbness, or pain relief at a site in a patient comprisingadministering at the site a multiparticulate unit dose of a local anesthetic selected from the group consisting of bupivacaine, dibucaine, etidocaine, tetracaine, lidocaine, xylocaine and salts thereof incorporated into particles of a biocompatible, biodegradable polymer selected from the group consisting of polymers of lactic acid, glycolic acid, and copolymers thereof, the particles being selected from the group consisting of microparticles, microspheres, and microcapsules, wherein the local anesthetic is included in the unit dose in an amount effective to achieve nerve blockade, local numbness, or pain relief at the site and is incorporated into the particles in a percent loading of between 5 and 90% by weight, and an amount of a glucocorticoid effective to prolong the nerve blockade or pain relief provided by the local anesthetic for a time period greater than that obtained by the use of the local anesthetic incorporated in the polymer in the absence of the glucocorticoid.
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Accused Products
Abstract
Biodegradable controlled release microspheres for the prolonged administration of a local anesthetic agent, and a method for the manufacture thereof are disclosed. The microspheres are formed of a biodegradable polymer degrading significantly within a month, with at least 50% of the polymer degrading into non-toxic residues which are removed by the body within a two week period. Useful polymers include polyanhydrides, polylactic acid-glycolic acid copolymers and polyorthoesters containing a catalyst; polylactic acid-glycolic acid copolymers are preferred. Local anesthetics are incorporated into the polymer using a method that yields a uniform dispersion, preferably solvent casting. Prolonged release is obtained by incorporation of a glucocorticoid into the polymeric matrix or by co-administration of the glucocorticoid with the microspheres. The type of anesthetic and the quantity are selected based on the known pharmaceutical properties of these compounds.
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Citations
32 Claims
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1. A method for prolonged nerve blockade, local numbness, or pain relief at a site in a patient comprising
administering at the site a multiparticulate unit dose of a local anesthetic selected from the group consisting of bupivacaine, dibucaine, etidocaine, tetracaine, lidocaine, xylocaine and salts thereof incorporated into particles of a biocompatible, biodegradable polymer selected from the group consisting of polymers of lactic acid, glycolic acid, and copolymers thereof, the particles being selected from the group consisting of microparticles, microspheres, and microcapsules, wherein the local anesthetic is included in the unit dose in an amount effective to achieve nerve blockade, local numbness, or pain relief at the site and is incorporated into the particles in a percent loading of between 5 and 90% by weight, and an amount of a glucocorticoid effective to prolong the nerve blockade or pain relief provided by the local anesthetic for a time period greater than that obtained by the use of the local anesthetic incorporated in the polymer in the absence of the glucocorticoid.
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11. A formulation for prolonged nerve blockade, local numbness, or pain relief at a site in a patient comprising
a unit dose of a local anesthetic selected from the group consisting of bupivacaine, dibucaine, etidocaine, tetracaine, lidocaine, xylocaine and salts thereof incorporated into a biocompatible, biodegradable polymer selected from the group consisting of polymers of lactic acid, glycolic acid, and copolymers thereof, wherein the local anesthetic is included in the unit dose in an amount effective to achieve nerve blockade, local numbness, or pain relief at the site and is incorporated into the polymer in a percent loading of between 5 and 90% by weight, and an amount of a glucocorticoid effective to prolong the nerve blockade, local numbness, or pain relief provided by the local anesthetic for a time period greater than that obtained by the use of the local anesthetic incorporated into the polymer in the absence of the glucocorticoid.
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25. A formulation for prolonged nerve blockade, local numbness, or pain relief at a site in a patient comprising
a unit dose of a local anesthetic incorporated into a biocompatible, biodegradable polymer in the form of microspheres, the local anesthetic being included in the unit dose in an amount effective to achieve nerve blockade, local numbness, or pain relief at the site and being incorporated into the polymer in a percent loading of 5 to 90% by weight, and an amount of a glucocorticoid effective to prolong the nerve blockade, local numbness, or pain relief provided by the local anesthetic for a time period greater than that obtained by the use of the local anesthetic incorporated into the polymer in the absence of the glucocorticoid.
Specification