Bioerodible film for ophthalmic drug delivery

This application claims priority to U.S. Provisional Applications, U.S. Ser. No. 60/395,840 filed Jul. 15, 2002, and U.S. Ser. No. 60/432,721, filed Dec. 12, 2002.

This invention relates to drug delivery compositions. In particular, this invention relates to the use of bioerodible materials as drug delivery films that are particularly useful in ophthalmic drug delivery. The drug delivery films of the present invention are especially suited for delivering anti-proliferative agents, such as paclitaxel or camptothecin, to maintain bleb function in glaucoma filtration surgery.

Paclitaxel or “taxol” has reportedly been used to maintain bleb function in glaucoma filtration surgery. Paclitaxel has been delivered in films prepared from biodegradable polymers, such as polyanhydrides or polylactides) or from non-degradable, non-erodible polymers, such as ethylene vinyl acetate. The disadvantage with biodegradable polymers is that it is difficult to biodegrade them in very short period, e.g., less than one week. Non-biodegradable, non-erodible drug dosage forms either stay forever, or have to be removed surgically.

Anti-proliferative agents used in connection with glaucoma filtration surgery have been delivered to the eye using bioerodible polymers. See, for example, Lee, et al., Ophthalmology 103(5):800-807 (May 1996). See also, Lee et al., Investigative Ophthalmology & Visual Science 29:1692-1697 (1988); and Uppal, et al., J. Ocular Pharmacology, 10(2):471-479 (1994).

What are needed are improved bioerodible drug delivery films that are suitable for delivering drugs to the eye.

The present invention provides bioerodible drug delivery films that are particularly suitable for ophthalmic drug delivery. The film compositions contain (i) a water-soluble, film-forming polymer and (ii) a fatty acid glyceride or ester. The drug delivery films are suitable for delivering any ophthalmically acceptable drug and are especially useful as subconjunctival or sub-Tenon's implants.

The drug delivery films of the present invention are more flexible than bioerodible films containing a water-soluble, film-forming polymer and lacking a fatty acid glyceride or ester. Without intending to be bound to any theory, it is believed that the fatty acid glyceride or ester ingredient slows dissolution of the film and may slow release of drug from the film.

One additional advantage that the drug delivery films of the present invention possess is that they are bioadhesive and, when used in connection with glaucoma filtration surgery to deliver an anti-proliferative agent, do not require suturing to maintain their position after implantation.

FIG. 1 compares the drug release profiles from drug delivery film compositions using the simple drug release method described in Example 2.

FIG. 2 compares the drug release profiles from drug delivery film compositions using the more sensitive drug release method described in Example 3.

FIG. 3 compares the drug release profiles from five drug delivery film compositions: four compositions containing the same amount of different fatty acid glyceride ingredients and one composition containing no fatty acid glyceride ingredient (Samples H, M, N, O and R).

FIG. 4 compares the drug release profiles from four drug delivery film compositions containing varying amounts of the same fatty acid glyceride ingredient (Samples E, H, W and R).

Unless indicated otherwise, all ingredient amounts expressed in percentage terms are presented as % w/w.

The drug delivery film compositions of the present invention contain (i) a water-soluble, film-forming polymer and (ii) a fatty acid glyceride or ester. Water-soluble, film-forming polymers are known and include, but are not limited to, hydroxypropyl cellulose, polyvinyl alcohol, polyacrylic acid, hydroxypropylmethyl cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose. Such polymers are commercially available or can be made by methods known in the art. Preferred water-soluble, film-forming polymers are hydroxypropyl cellulose, polyvinyl alcohol, and carboxymethyl cellulose. The most preferred water-soluble, film-forming polymer for use in the drug delivery film compositions of the present invention is hydroxypropyl cellulose. In general, the drug delivery film compositions of the present invention will contain an amount of water-soluble, film-forming polymer equal to 25-99.5% of the total composition weight.

As used herein, “water-soluble, film-forming polymer” does not include polymers that are only biodegradeable but not water soluble, such as polyanhydrides and polylactides (e.g., polylactic glycolic acid or “PLGA”), nor polymers that are neither biodegradable not water-soluble, such as ethyl vinyl acetate.

Preferably, the only polymeric ingredient contained within the compositions of the present invention is a water-soluble, film-forming polymer.

In addition to the water-soluble, film-forming polymer, the compositions of the present invention also contain a fatty acid glyceride or ester having a molecular weight of 150-4000, wherein the fatty acid glyceride or ester has the formula below.

wherein

R 1 , R 2 and R 3 are independently —H, —OH, —COOH, —C n H 2n+1-2m , —OOCC n H 2n+1-2m , —COOC n H 2n+1-2m , —COO(CH 2 CH 2 O) n CH 2 CH 2 OH, —C n H 2n+1-2m COO(CH 2 CH 2 O) n CH 2 CH 2 OH, —OC n H 2n+1-2m COO(CH 2 CH 2 O) n CH 2 CH 2 OH, —OOCC n H 2n+1-2m COOC n′ H 2n′+1-2m′ ; n and n′ are independently 0-50; and m and m′ are independently 0-10.

Fatty acid glycerides and esters of formula (I) are known. Such compounds are commercially available or can be made by methods known in the art. For example, mono-, di-, and triglyceride compounds are commercially available from such suppliers as NuChek Prep (Elysian, Minn.), Quest International (Hoffman Estates, Ill.) and Eastman Chemical Company (Kingsport, Tenn.), which produces such compounds under the Myverol® and Myvace® brands, and Gattefosse (Saint-Priest, France), which produces such compounds under the Gelucire®, Suppocire™, Ovucire™, and Monosteo® brands.

Preferred are the compounds of formula (I) wherein

R 1 , R 2 and R 3 are independently —H, —OH, —COOH, —C n H 2n+1-2m , or —OOCC n H 2n+1-2m ;

n and n′ are independently 0-25; and

m and m′ are independently 0-3.

One commercially available fatty acid glyceride of formula (I) for use in the drug delivery film compositions of the present invention is the monoglyceride commercially available as Myverol® 18-92, available from Eastman Chemical Company. Myverol® 18-92, a distilled product of the glycerolysis of refined sunflower oil, has the following fatty acid distribution according to its manufacturer: 7.0% glyceryl monopalmitate (C16:0), 4.5% glyceryl monostearate (C18:0), 18.7% glyceryl monooleate (C18:1), and 67.5% glyceryl monolinoleate (C18:2).

Preferably, the drug delivery film compositions of the present invention contain a single fatty acid glyceride or mixture of fatty acid glycerides of formula (I) having a melting point ≦46° C. Most preferably, the single fatty acid glyceride or mixture of fatty acid glycerides of formula (I) has a melting point ≦42° C.

The drug delivery film compositions contain an amount of a fatty acid glyceride or ester ingredient equal to 0.5-25% of the weight of the water-soluble, film-forming polymer. Preferably, the amount of the fatty acid glyceride or ester ingredient in the drug delivery film compositions is equal to 1-10% of the weight of the water-soluble, film-forming polymer. Most preferably, the amount of fatty acid glyceride or ester ingredient is equal to 3-5% of the weight of the water-soluble, film-forming polymer.

The drug delivery film compositions of the present invention also comprise an ophthalmically acceptable drug. Such drugs include, but are not limited to, antibiotic, anti-inflammatory, anti-glaucoma, and anti-proliferative drugs. A preferred drug is paclitaxel. The amount of drug contained within the compositions of the present invention will vary depending upon the nature and severity of the condition to be treated, as well as the site of implantation in the patient and the identity of the drug. In general, however, the drug delivery film will contain an amount of drug equal to 0.0001-25% of the drug delivery film composition.

In addition to (i) an ophthalmic drug, (ii) a water-soluble, film-forming polymer, and (iii) a fatty acid glyceride or ester of formula (I) having a molecular weight of 150-4000, the drug delivery film compositions of the present invention optionally comprise one or more excipients. Many excipients for pharmaceutical compositions are known. Examples of suitable excipients include, but are not limited to: surfactants and stabilizers. Suitable surfactants include tyloxapol, polysorbate 20, polysorbate 60, polysorbate 80, and polyethoxylated castor oil derivatives (such as Cremophor EL and HCO-40). Suitable stabilizers include chelating agents, such as edetate disodium, and antioxidants, such as ascorbic acid and citric acid.

The compositions may be fashioned into a film of any shape suitable for insertion into the eye. Such shapes include, but are not limited to circular, rectangular, square and triangular shapes. For example, where the drug delivery film compositions of the present invention contain paclitaxel and are intended for use in glaucoma filtration surgery, the film may be fashioned as a 4.8 mm 2 disc that is 0.1-0.6 mm in height.

In one embodiment, the compositions of the present invention are used in connection with penetrating (e.g., trabeculectomy) and non-penetrating (e.g., viscocanalostomy) glaucoma filtration surgery. The label “penetrating” or non-penetrating” refers to whether the surgery involves penetrating into the anterior chamber. As part of both types of glaucoma filtration surgery, a bleb is surgically created as a reservoir for the outflow of aqueous humor. After the bleb is surgically created, a drug delivery film of the present invention containing an anti-proliferative drug is placed in the bleb to maintain bleb function by reducing or eliminating tissue growth or wound healing that would close the bleb. Preferably, the film contains the anti-proliferative drug paclitaxel in an amount such that the film delivers a total dose of 80-100 μg to a patient. In an especially preferred embodiment, the film is a 4.8 mm 2 disc that is 0.4-0.6 mm in height and contains 0.5-1% (w/w) of paclitaxel. Preferably, the drug delivery film of the present invention is used in connection with non-penetrating glaucoma filtration surgery.

The drug delivery film compositions of the present invention are particularly suitable for use as subconjunctival or sub-Tenon's implants, but also may be used in other locations within the eye, including intravitreal locations.

The following examples are intended to illustrate, but not limit, the present invention.