US Patent 8,337,886: Claim Scope, Formulation Coverage, and Patent-Landscape Analysis

US Patent 8,337,886 covers enteric-coated, controlled-release pellets for intestinal delivery of 5-aminosalicylic acid and related anti-inflammatory compounds. Its strongest protection is concentrated in a specific multiparticulate architecture: a homogeneous drug-polymer core, a water-permeable but intestinally insoluble non-gel-forming polymer matrix, and an enteric coating. The patent also claims extrusion, cutting, spheronization, drying, capsule and sachet presentation, and maintenance treatment for ulcerative colitis.

The independent claims divide the estate into three enforcement categories:

Claim 1: a formulation defined partly by a manufacturing process.
Claim 19: a broader formulation claim focused on composition and polymer selection.
Claim 29: a method-of-treatment claim linked back to the formulation of claim 1.

The principal design-around opportunities are substitution of the matrix polymer, use of a different pellet-manufacturing process, elimination or modification of the enteric coating, and use of a noncovered active ingredient. The main infringement risk is for mesalamine or related 5-ASA pellets using Eudragit-type matrix polymers, enteric coating, and extrusion-spheronization.

What does US Patent 8,337,886 protect?

The patent protects a controlled-release pellet formulation with the following required elements:

Claim element	Required feature
Dosage form	Pellet formulation for intestinal treatment
Core	Homogeneous dispersion of active compound in a polymer matrix
Matrix	Non-gel-forming, essentially insoluble in the intestinal tract, permeable to intestinal fluid
Coating	Enteric coating
Manufacturing process in claim 1	Mixing, additive incorporation, moist-mass extrusion, and related pellet processing
Matrix polymers in dependent claims	Poly(ethyl acrylate, methyl methacrylate) or poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride)
Active ingredients	5-aminosalicylic acid, balsalazide, sulfasalazine, or acceptable salts
Therapeutic use	Ulcerative colitis, Crohn's disease, colorectal conditions, and maintenance of remission
Presentation	Capsules or sachets
Pellet size	Approximately 0.1 mm to 3 mm

The patent does not claim every enteric-coated mesalamine product. Coverage depends on the combination of the drug, pellet core, matrix properties, coating, and, for certain claims, manufacturing limitations.

How are the independent claims structured?

Claim 1: Formulation plus process limitations

Claim 1 is a product claim drafted with process language. The formulation must contain:

A core;
A homogeneously dispersed active compound;
A non-gel-forming polymer matrix;
An enteric coating;
A matrix that is essentially insoluble in intestinal conditions and permeable to intestinal fluid.

The claim also states that the formulation is made by mixing the active compound and matrix polymer, adding a pharmaceutically acceptable additive, and extruding a moist mass.

This creates two interpretive issues.

First, the claim contains both structural and process-related limitations. A competing product may argue that the extrusion language limits the claim to products made by the specified process. The patent holder may argue that the process language describes characteristics of the claimed product rather than imposing a separate manufacturing requirement.

Second, "homogeneously dispersed" is a potentially important limitation. A pellet with drug concentrated in a coating, layered around a central core, or distributed in discrete drug-rich domains may fall outside the literal scope, depending on analytical evidence.

Claim 19: Composition-focused independent claim

Claim 19 is the commercially more important composition claim because it omits the express extrusion-process language found in claim 1. It requires:

A controlled-release intestinal pellet;
A homogeneous drug dispersion in a non-gel-forming matrix;
An enteric coating;
A matrix that is essentially insoluble but permeable to intestinal fluids;
Matrix polymer content of at least 1% of core weight;
One of two specified polymer families.

Claim 19 is narrower in polymer identity but potentially stronger against manufacturing-process design-arounds. A manufacturer could avoid an extrusion limitation yet remain exposed if it uses one of the claimed polymer systems and satisfies the remaining structural limitations.

Claim 29: Maintenance-treatment method

Claim 29 covers administering a formulation "as defined in claim 1" to maintain remission of ulcerative colitis. Because it incorporates claim 1, the method claim carries the formulation limitations of that claim, including the matrix, enteric coating, and process-defined formulation characteristics.

The claim is directed to use rather than manufacture or sale. Its practical value depends on:

The approved indication;
The product label;
Prescriber behavior;
Whether the accused product is promoted for maintenance of remission;
The availability of induced or contributory infringement theories.

A product marketed solely for another indication may create a narrower method-of-use exposure, although label language is not the only relevant evidence in an infringement analysis.

What active ingredients and diseases are covered?

Active ingredients

Claims 13, 20, and 30 identify:

5-aminosalicylic acid, also called mesalamine;
Balsalazide;
Sulfasalazine;
Pharmaceutically acceptable salts.

The patent therefore targets a defined 5-ASA and related intestinal anti-inflammatory product class. It does not, on the face of the supplied claims, cover unrelated inflammatory bowel disease drugs such as corticosteroids, biologics, Janus kinase inhibitors, or interleukin inhibitors.

The active ingredient is not sufficient by itself to establish coverage. A conventional delayed-release mesalamine tablet, for example, would not necessarily meet the pellet, matrix, dispersion, and coating limitations.

Therapeutic indications

The claims identify:

Ulcerative colitis;
Crohn's disease;
Maintenance of remission of ulcerative colitis;
Prevention or treatment of recurrence of inflammatory intestinal disorders;
Formation of polyps;
Intestinal cancer;
Colorectal polyps;
Colorectal cancer.

Claims 14, 23, and 33 are unusually broad in listing cancer and polyp-related uses. Their commercial relevance depends on written-description support, enablement, prosecution history, regulatory labeling, and claim construction. The clearest practical indication is ulcerative colitis, particularly maintenance of remission.

What formulations are protected?

Core matrix

The core is the technical center of the patent. The matrix must be:

Non-gel-forming;
Essentially insoluble in the intestinal tract;
Permeable to intestinal fluid;
Capable of supporting controlled release;
Compatible with homogeneous drug dispersion.

This excludes many conventional hydrophilic controlled-release systems that form a gel barrier. A hydrogel matrix based on a swellable cellulose ether would present a strong noninfringement position if the matrix is materially gel-forming under intestinal conditions.

The phrase "essentially insoluble" does not necessarily require absolute insolubility. The claim is directed to a polymer that remains substantially intact while permitting fluid penetration and drug diffusion.

Claimed matrix polymers

Claim 11 and claim 19 identify two polymer categories:

Poly(ethyl acrylate, methyl methacrylate).
Poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride).

These correspond to acrylic copolymer systems used in controlled-release pharmaceutical coatings or matrices. Commercial products may use different grades, ratios, excipients, or trade-designated polymers. Chemical identity, monomer ratio, ionic functionality, and product specifications would determine whether a particular polymer falls within the claim.

A formulation using ethylcellulose, a gel-forming polymer, a lipid matrix, a pH-dependent polymer as the principal matrix, or a different acrylic copolymer may have a stronger design-around position. That assessment requires comparison of the polymer's composition and functional behavior.

Enteric coating

Claims 1 and 19 require an enteric coating. Dependent claims identify:

A methacrylic acid-containing copolymer;
Methylhydroxypropyl cellulose phthalate;
A 1:1 copolymer of methacrylic acid and methyl methacrylate.

Claim 10 specifies a coating composition containing:

Poly(methacrylic acid, methyl methacrylate) 1:1;
Ethanol and water;
Triethyl citrate;
Talc;
Titanium dioxide;
Magnesium stearate.

Claim 10 is narrow. It requires the specified coating preparation and listed ingredients. A competing enteric coating could avoid claim 10 while still infringing broader claims if it satisfies the coating requirement of claim 1 or claim 19.

Pellet size and processing

The claims cover pellets approximately 0.1 mm to 3 mm in size. Claim 6 adds pieces approximately 1 mm long before rounding. Claims 7 through 9 add:

Spheronization;
Drying;
Drying at approximately 60°C.

These limitations create a hierarchy:

Processing feature	Claim coverage
Moist-mass extrusion	Claim 1
Cutting into pieces	Claim 5
Approximately 1 mm pieces	Claim 6
Spheronization	Claim 7
Drying	Claim 8
Drying at approximately 60°C	Claim 9
Specific enteric-coating process	Claim 10

The independent composition claim does not expressly require spheronization or a 60°C drying step. Those limitations are therefore more useful for narrowing the patent than for defining the core commercial coverage.

How strong is the patent estate?

Based on the supplied claims, the estate has moderate formulation strength and narrower process strength.

Strongest features

The most defensible commercial features are:

The combination of homogeneous drug dispersion and non-gel-forming acrylic matrix;
The matrix's intestinal insolubility and fluid permeability;
The required enteric coating;
The specified acrylic polymer families in claim 19;
The 1% minimum matrix concentration;
The use of mesalamine or related 5-ASA compounds in claims 20 and 30.

Claim 19 is the central claim for product screening because it does not require the extrusion process stated in claim 1 and identifies the relevant polymer families directly.

Vulnerable features

Potential validity and enforcement vulnerabilities include:

Functional terms such as "essentially insoluble," "permeable," and "homogeneously dispersed";
Potential overlap with earlier multiparticulate mesalamine and acrylic-polymer disclosures;
The use of process limitations in claim 1;
Broad disease and cancer-use language;
Possible obviousness combinations involving known mesalamine pellets, enteric coatings, acrylic polymers, and extrusion-spheronization;
The breadth of the claim relative to the examples and demonstrated formulations.

A prior-art attack would likely focus on whether earlier references disclose the claimed combination rather than each element separately. A formulation with mesalamine dispersed in an acrylic matrix and protected by an enteric film would be the most relevant prior-art profile.

Which products face the greatest generic-entry risk?

Products with the following attributes present the highest risk of literal or substantially equivalent coverage:

Product characteristic	Risk level
Mesalamine or another listed 5-ASA	High
Multiparticulate pellets, 0.1-3 mm	High
Drug homogeneously dispersed throughout the core	High
Acrylic, non-gel-forming, water-permeable matrix	High
Enteric coating over the matrix pellets	High
Capsule or sachet presentation	Moderate
Extrusion and spheronization	High for claim 1-related analysis
Alternative non-acrylic matrix	Lower
Tablet, granule, bead, or coating-only architecture	Potentially lower
Gel-forming matrix	Lower
No enteric coating	Lower

Capsules and sachets are not independently decisive. They are dependent limitations in claims 21, 22, 31, and 32. A product can infringe a broader formulation claim without being sold in both presentations, provided the other required elements are present.

What design-arounds are available?

A generic or follow-on manufacturer could assess the following alternatives:

Change the matrix polymer

Use a matrix that is not one of the specified acrylic copolymers and does not perform as a substantially equivalent non-gel-forming acrylic system.

Use a different drug-distribution architecture

A layered pellet, drug-loaded coating, coated inert seed, or nonhomogeneous core may avoid the "homogeneously dispersed" limitation. The technical distinction must be supported by microscopy, content-uniformity testing, cross-sectional analysis, and manufacturing records.

Eliminate the enteric coating

A formulation that relies on a pH-independent controlled-release system or a different gastrointestinal targeting mechanism may avoid the express enteric-coating requirement. This approach may affect protection from gastric conditions and release performance.

Use a different manufacturing process

A manufacturer could use fluid-bed layering, powder layering, rotary processing, hot-melt processing, or another technique rather than moist-mass extrusion. This is most relevant to claim 1 and its dependent process claims. It has less value against claim 19 if the final product satisfies the composition limitations.

Move outside the claimed pellet size

A dosage form materially outside the 0.1 mm to 3 mm range could avoid claims 18 and 27, but those are dependent claims. Size alone would not avoid claims 1 or 19 unless the independent claims are construed to require pellet dimensions through incorporation or prosecution history.

Change the dosage form

A tablet, matrix tablet, capsule containing nonpellet granules, or other dosage form may avoid the pellet-specific claims. The risk depends on whether the product still contains pellets as claimed.

What is the likely regulatory and Orange Book relevance?

The supplied information does not establish whether US Patent 8,337,886 is listed in the FDA Orange Book, whether it has been delisted, or whether it is associated with an approved drug application. A patent number alone does not establish Orange Book status.

The patent appears directed to a drug product formulation and a method of maintaining ulcerative-colitis remission. If listed for an approved product, an abbreviated new drug application applicant could address it through:

Paragraph III certification, if the patent has not expired;
Paragraph IV certification, if the applicant asserts invalidity, unenforceability, or noninfringement;
A statement that the patent is not applicable or is not listed, depending on the Orange Book record.

Patent listing and regulatory exclusivity are separate. FDA approval may be affected by listed patents, but the patent does not itself create five-year chemical exclusivity, three-year new clinical investigation exclusivity, or seven-year orphan-drug exclusivity.

When does US Patent 8,337,886 lose exclusivity?

The expiration date cannot be calculated reliably from the patent number and claims alone. US patent term depends on:

The earliest effective nonprovisional filing date;
Any priority applications;
Patent-term adjustment;
Patent-term extension;
Terminal disclaimers;
Reissue or other post-grant events.

The claims supplied do not provide those data. Accordingly, the patent's enforceable expiration date, current maintenance status, terminal disclaimer status, and patent-term adjustment cannot be stated accurately.

What patent litigation and Paragraph IV challenges affect the patent?

The supplied material contains no litigation history, Paragraph IV notice, district-court docket, Federal Circuit decision, settlement agreement, or FDA patent-listing record. The claim text alone cannot establish:

Whether a generic applicant has challenged the patent;
Whether litigation was filed;
Whether a 30-month stay was triggered;
Whether the patent was asserted or dismissed;
Whether a settlement permits an agreed launch date;
Whether the patent has been held invalid, unenforceable, or not infringed.

Any litigation conclusion would be unsupported without the underlying court and FDA records.

How does this patent compare with biologic and conventional generic risk?

This is a small-molecule formulation patent. Biosimilar risk is therefore not the relevant pathway. The relevant competitors are:

Generic mesalamine products;
Balsalazide products;
Sulfasalazine products;
Follow-on multiparticulate formulations;
Brand or authorized-generic versions;
Products using alternative release technologies.

A biosimilar does not ordinarily challenge this patent because biosimilar approval concerns biologic products. A conventional ANDA applicant would face the more relevant patent-certification and formulation-equivalence questions.

What manufacturing and IP barriers matter most?

The principal manufacturing barrier is achieving reproducible drug distribution within a polymer matrix while maintaining:

Pellet size uniformity;
Mechanical strength;
Controlled permeability;
Enteric resistance;
Release in the intended intestinal region;
Batch-to-batch coating uniformity.

The process claims add extrusion, cutting, spheronization, and drying parameters. Those steps may be valuable operationally even where they are difficult to enforce independently. Manufacturing records, in-process specifications, polymer certificates, coating formulas, and dissolution profiles would be central to an infringement investigation.

The largest IP barrier is claim 19 because it targets the finished composition rather than only the manufacturing sequence. A process change may therefore reduce risk under claim 1 while leaving substantial exposure under claim 19.

Key Takeaways

US Patent 8,337,886 is directed to enteric-coated controlled-release intestinal pellets.
Claim 19 is the principal composition claim because it focuses on acrylic matrix identity and omits the express extrusion-process limitation.
The most relevant actives are mesalamine, balsalazide, sulfasalazine, and their acceptable salts.
The core technical combination is homogeneous drug dispersion in a non-gel-forming, intestinally insoluble, fluid-permeable matrix.
Enteric coating is required by the principal formulation claims.
Extrusion, cutting, spheronization, drying, and 60°C drying are narrower process limitations.
Capsules and sachets are dependent presentation claims, not the core scope.
The strongest design-arounds involve changing the matrix polymer, drug-distribution architecture, dosage form, or enteric-release mechanism.
The patent is relevant to generic formulation risk, not biosimilar risk.
The supplied claims do not establish the patent's expiration date, Orange Book listing, litigation history, Paragraph IV activity, settlement status, or current enforceability.

References

United States Patent and Trademark Office. (n.d.). US Patent No. 8,337,886, controlled release pellet formulation. Claims supplied in the request.
United States Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
United States Food and Drug Administration. (n.d.). Abbreviated new drug application submissions: Patent certifications and the 30-month stay. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/anda-submissions-patent-certifications-and-30-month-stay
United States Code, 35 U.S.C. §§ 154, 156. Patent term and patent term extension.
United States Code, 21 U.S.C. § 355(j). Abbreviated applications and patent certifications.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	197 32 903	Jul 30, 1997

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	241964	⤷ Start Trial
Canada	2297832	⤷ Start Trial
Germany	19732903	⤷ Start Trial
Germany	59808642	⤷ Start Trial
Denmark	0977557	⤷ Start Trial
European Patent Office	0977557	⤷ Start Trial
Spain	2196556	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,337,886

Summary for Patent: 8,337,886