Biodegradable polymeric article for dispensing drugs

Claim 2

AN ARTICLE FOR CONTROLLABLY DISPENSING DRUGS COMPRISING: A. A PLURALITY OF SPHEROIDAL SHAPED, HOMOPOLYMERS AND COPOLYMERS OF LACTIC ACID, SAID POLYMERS BEING PREPARED FROM CYCLIC ESTERS OF OPTICALLY ACTIVE OR INACTIVE LACTIVE ACIDS, OR MIXTURES THEREOF, HAVING A SUFFICIENTLY HIGH MOLECULAR WEIGHT TO RETAIN STRUCTURAL INTEGRITY OF SAID SPHEROIDS FOR AN EFFECTIVE PERIOD OF TIME UPON IMPLANTATION, WITH THE PROVISO THAT CRYSTALLINE SPHEROIDS HAVING RELATIVELY LONG DURATION UPON IMPLATATION ARE FORMED FROM PURE OPTICALLY ACTIVE LACTIC ACIDS AND SPHEROIDS HAVING RAPID RELEASE UPON IMPLANTATION ARE FORMED FROM LACTIC ACID POLYMERS HAVING A LOWER DEGREE OF CRYSTALLINITY WITH B. AN EFFECTIVE AMOUNT OF A SOLUTION OF A DRUG SAD SOLUTION OF DRUG SUBSTANTIALLY AT THE CENTER OF SAID SPHEROIDS EXUDING OR MIGRATING, UPON IMPLANTATION, FROM THE INTERIOR TO THE SURFACE OF THE SPHEROID UNTIL SAID SURFACE IS COATED WITH A DRUG AND AN EQUILIBRIUM IS ESTABLICHED BETWEEN THE SURFACE LAYER AND THE DRUG AT THE INTERIOR OF THE POLYMERIC MATERIAL SUCH IF THE SURFACE LAYER IS PARTIALLY OR TOTALLY REMOVED THE EQUILIBRIUM IS DESTROYED AND FURTHER AMOUNTS OF THE DRUG MIGRATE TO THE SURFACE UNTIL EQUILIBRIUM IS REESTABLISHED SO THAT THIS CYCLE REPEATS ITSELF UNTIL THE SUPPLY OF DRUG IS EXHAUSTED.

Claim 3

An article for controllably dispensing drugs comprising: a. a plurality of spheroidal shaped, homopolymers and copolymers of lactic acid, said polymers being prepared from cyclic esters of optically active or inactive lactic acids, or mixtures thereof, having a sufficiently high molecular weight to retain structural integrity of said spheroids for an effective period of time upon implantatioN, with the proviso that crystalline spheroids having relatively long duration upon implantation are formed from pure optically active lactic acids and spheroids having rapid release upon implantation are formed from lactic acid polymers having a lower degree of crystallinity with b. an effective amount of a solution of a drug said solution of drug substantially at the center of said spheroids exuding or migrating, upon implantation, from the interior to the surface of the spheroid until said surface is coated with a drug and an equilibrium is established between the surface layer and the drug at the interior of the polymeric material such that if the surface layer is partially or totally removed the equilibrium is destroyed and further amounts of the drug migrate to the surface until equilibrium is reestablished so that this cycle repeats itself until the supply of drug is exhausted.

Claim 4

An article for controllably dispensing drugs comprising: a. a plurality of spheroidal shaped, homopolymers and copolymers of lactic acid, said polymers being prepared from cyclic esters of optically active or inactive lactic acids, or mixtures thereof, having a sufficiently high molecular weight to retain structural integrity of said spheroids for an effective period of time upon implantatioN, with the proviso that crystalline spheroids having relatively long duration upon implantation are formed from pure optically active lactic acids and spheroids having rapid release upon implantation are formed from lactic acid polymers having a lower degree of crystallinity with b. an effective amount of a solution of a drug said solution of drug substantially at the center of said spheroids exuding or migrating, upon implantation, from the interior to the surface of the spheroid until said surface is coated with a drug and an equilibrium is established between the surface layer and the drug at the interior of the polymeric material such that if the surface layer is partially or totally removed the equilibrium is destroyed and further amounts of the drug migrate to the surface until equilibrium is reestablished so that this cycle repeats itself until the supply of drug is exhausted.

Claim 5

An article according to claim 1 wherein said drug comprises a contraceptive steroid present in an effective contraceptive amount.

Claim 6

An article according to claim 2 wherein said contraceptive steroid comprises a progestin.

Claim 7

An article according to claim 2 wherein said contraceptive steroid comprises a combination of a progestin and an estrogen.

Claim 8

A method for administering predetermined, effective amounts of a drug from an implant to a mammal which comprises implanting the article of claim 1 in a mammal whereby said predetermined effective amount of the drug is released and administered to said mammal.

Claim 9

A method according to claim 5 wherein said drug comprises a contraceptive steroid present in an effective contraceptive amount.

Claim 10

A method according to claim 6 wherein said contraceptive steroid comprises a progestin.

Claim 11

A method according to claim 6 wherein said contraceptive steroid comprises a combination of a progestin and an estrogen.