US Patent 8,916,588: Methylphenidate Delayed-Release Patent Scope, Claims and Competitive Landscape
US Patent 8,916,588 protects methods of treating attention-deficit disorders and other methylphenidate-responsive conditions with a night-administered, delayed-release and sustained-release oral formulation. The independent claims are defined primarily by pharmacokinetic performance rather than by methylphenidate alone.
The patent’s central limitations are:
- A minimum five-hour lag period.
- Plasma methylphenidate below 10% of Cmax during the lag period.
- AUC0-10 below approximately 7% of AUC0-48.
- Tmax between 12 and 19 hours.
- A multilayer bead or coated-core formulation.
- In several claims, specific coating polymers and excipients.
- Use in ADHD and related disorders, including binge-eating disorder and depressive conditions.
The claim structure is directed to a product-method combination. A competing product may avoid literal infringement by failing the claimed pharmacokinetic thresholds, using a different dosage architecture, or omitting the claimed coating composition. It may still face infringement risk under the doctrine of equivalents, depending on prosecution history and claim construction.
What drug technology does US Patent 8,916,588 protect?
The patent covers orally administered methylphenidate formulations designed for evening dosing and drug release after sleep. The formulation has a delayed-release barrier surrounding a sustained-release layer and a methylphenidate-containing core.
The technical objective is to minimize methylphenidate exposure overnight, then provide therapeutic concentrations after awakening. Claim 7 expressly links the lag period to sleep and requires therapeutic absorption upon awakening.
Core formulation architecture
The main formulation disclosed by the claims has three structural levels:
| Layer |
Claimed function |
Representative materials |
| Drug core |
Contains methylphenidate or a pharmaceutical salt and excipients |
Methylphenidate HCl and pharmaceutically acceptable excipients |
| Sustained-release layer |
Controls subsequent drug release |
Ethyl cellulose, hydroxypropyl cellulose, dibutyl sebacate, magnesium stearate |
| Delayed-release layer |
Prevents early release in acidic conditions |
Methacrylic acid copolymer type-B, mono- and di-glycerides, polysorbate 80 |
Claim 24 is the most formulation-specific claim. It requires a water-soluble capsule containing multiple beads. Each bead must contain the core, the sustained-release layer and the delayed-release layer.
The claims also cover spherical cores and non-pareil beads coated with methylphenidate. The claimed unit dose ranges from 5 mg to 150 mg, with a specific 80 mg embodiment in claim 28.
How do the independent claims differ?
Claims 1, 17 and 24 are the principal independent claims.
| Claim |
Primary focus |
Key limitations |
| 1 |
Treatment method using multilayer formulation |
Core, sustained-release layer, delayed-release layer, lag period, AUC and Tmax |
| 17 |
Treatment method using an acid-insoluble outer coating |
Coating insoluble below pH 5.5, pharmacokinetic thresholds, ADHD/ADD |
| 24 |
Specific multiparticulate formulation used to treat ADHD/ADD |
Water-soluble capsule, beads, specified polymers and excipient ranges |
Claim 1: broadest technical method claim
Claim 1 requires:
- Treatment of a methylphenidate-responsive disorder.
- Oral administration.
- Methylphenidate or a pharmaceutical salt.
- A core containing drug and excipient.
- A sustained-release layer around the core.
- A delayed-release layer around the sustained-release layer.
- A five-hour or longer lag period.
- Plasma concentration below 10% of Cmax during the lag period.
- AUC0-10 below approximately 7% of AUC0-48.
- Tmax between 12 and 19 hours.
The claim does not require a capsule, bead, specific polymer or specific dose. It therefore has broader structural coverage than claim 24, but its pharmacokinetic requirements create a significant infringement proof burden.
Claim 17: coating-focused method claim
Claim 17 substitutes a more general formulation description for the three-layer structure. It requires a sustained-release formulation enclosed in an outer coating insoluble in aqueous medium below pH 5.5.
This claim may reach formulations that achieve the claimed pharmacokinetic profile without using the exact three-layer bead configuration in claim 1. Claim 20 narrows the coating to methacrylic acid copolymer type-B, mono- and di-glycerides, and polysorbate 80.
Claim 24: strongest structural formulation claim
Claim 24 is narrower but more directly testable. It requires:
- A water-soluble capsule.
- Multiple beads.
- A methylphenidate-containing core.
- A sustained-release layer containing specified components and ratios.
- A delayed-release layer containing specified components.
The claim requires ethyl cellulose and hydroxypropyl cellulose in a ratio of approximately 1:3 to 1:5, dibutyl sebacate, and 25% to 50% magnesium stearate in the sustained-release layer.
The delayed-release layer must include methacrylic acid copolymer type-B, mono- and di-glycerides, and polysorbate 80.
What pharmacokinetic profile is protected?
The patent protects a defined delayed-onset methylphenidate profile rather than a generic extended-release profile.
| Parameter |
Claimed threshold |
| Lag period |
At least 5 hours |
| Drug concentration during lag |
Less than 10% of Cmax |
| AUC0-10 |
Less than approximately 7% of AUC0-48 |
| AUC0-6, claim 2 |
Less than approximately 5% of AUC0-48 |
| AUC0-6, claim 3 |
Less than approximately 3% of AUC0-48 |
| Tmax |
12 to 19 hours |
| In vitro release |
No more than 10% released during first 5 hours under specified USP conditions |
Claims 16 and 23 add a release-rate shape requirement. During at least two one-hour periods before Tmax, the total plasma concentration must increase at an accelerating rate relative to the preceding one-hour period.
That limitation may distinguish the claimed profile from conventional extended-release methylphenidate products that produce an earlier or flatter concentration curve.
What formulations are protected by US 8,916,588?
The patent covers both broad formulation classes and narrow composition-specific embodiments.
Multilayer bead formulations
The core bead may be:
- A substantially spherical bead.
- A non-pareil bead coated with a methylphenidate layer.
- A drug-containing core with pharmaceutically acceptable excipients.
The bead is surrounded by a sustained-release coating and then a delayed-release coating. The beads are placed in a water-soluble capsule.
Acid-resistant outer coatings
Claim 17 requires an outer coating insoluble below pH 5.5. This limitation is directed to protection against early release in the stomach. Release occurs later as the dosage form reaches higher-pH intestinal conditions.
Abuse-deterrent embodiments
Claim 13 adds an abuse-deterrent agent. Claims 14 and 15 add a nasal irritant, including a capsaicinoid or sodium lauryl sulfate.
These limitations expand the patent into abuse-deterrent methylphenidate formulations. They do not apply to every formulation covered by the independent claims.
Which medical uses are protected?
Claim 4 lists a broad range of disorders and conditions:
- Attention deficit disorder.
- Attention deficit hyperactivity disorder.
- Excessive daytime sleepiness.
- Major depressive disorder.
- Bipolar depression.
- Schizophrenia.
- Chronic fatigue.
- Chemotherapy-associated fatigue.
- Binge-eating disorder.
Claim 5 focuses on ADD and ADHD. Claim 6 focuses on binge-eating disorder. Claims 17 and 24 are limited to ADD or ADHD treatment.
The method claims require administration of the claimed dosage form. A party using methylphenidate for ADHD with a conventional immediate-release or conventional extended-release tablet would not satisfy the formulation limitations solely because the active ingredient is the same.
How strong is the patent estate from an infringement perspective?
The patent has meaningful claim differentiation but also several enforcement vulnerabilities.
Strengths
The claims combine multiple independent limitations:
- Formulation structure.
- In vitro dissolution.
- Plasma pharmacokinetics.
- Administration timing.
- Therapeutic indication.
- Specific excipient compositions.
A competing product that reproduces the same delayed-release profile may face risk even if it changes capsule dimensions, bead size or dose.
The structural limitations in claim 24 are particularly useful for product testing. An accused product can be analyzed for the presence of the specified polymers, plasticizers and magnesium stearate range.
Vulnerabilities
The pharmacokinetic limitations may be difficult to prove in a commercial setting. A single patient’s concentration-time profile is unlikely to establish infringement. Testing may require a properly designed clinical or pharmacokinetic study.
The terms "about," "at least," "less than about" and "between 12 and 19 hours" create claim-construction issues. The parties may dispute:
- The acceptable tolerance around the AUC thresholds.
- Whether Tmax is measured by arithmetic mean, median or individual subject.
- The treatment of values below assay quantification.
- The definition of Cmax and the beginning of the lag period.
- Whether the dissolution test is an essential limitation or only a dependent limitation.
Claims 1 and 17 are method claims. Liability generally requires performance of the claimed treatment method or inducement of that conduct. Claims directed to the formulation itself would ordinarily provide a more direct basis for product-based enforcement, but claim 24 remains limited to use of the formulation in the claimed treatment method.
What generic entry risks exist?
A generic methylphenidate applicant could pursue several design-around strategies:
| Design-around strategy |
Potential effect |
| Tmax below 12 hours or above 19 hours |
Avoids a central pharmacokinetic limitation |
| AUC0-10 at or above the claimed threshold |
May avoid claims 1 and 17 |
| Release of more than 10% in the first five hours |
May avoid claims 12 and 22 |
| Different delayed-release polymer system |
May avoid composition-specific dependent claims |
| Tablet or osmotic system instead of multiparticulate beads |
May avoid claim 24 |
| Different sustained-release coating ratio |
May avoid claims 21 and 24 |
| Morning administration |
May avoid night-dosing claims, although not necessarily claim 1 |
| Different indication |
May avoid indication-limited claims 5, 6, 17 and 24 |
A formulation that achieves a similar clinical effect but does not meet the claimed Tmax, AUC or dissolution parameters may reduce literal infringement exposure. FDA approval, however, does not itself determine patent infringement.
What is the Orange Book and FDA relevance?
The patent claims describe a controlled-release methylphenidate product profile associated with a prescription ADHD product using evening administration. FDA approval of a product using this technology does not establish that every claim in US Patent 8,916,588 is listed in the Orange Book.
Orange Book relevance depends on whether the patent is listed against a specific approved drug product and whether its claims cover the approved drug, formulation or method of use under FDA listing rules. Patent listing and patent validity are separate questions. A listed patent may be challenged through a Paragraph IV certification, while an unlisted patent may still create litigation risk under other theories.
For a generic applicant, the relevant regulatory questions are:
- Whether the reference listed drug has an approved delayed-release methylphenidate formulation.
- Which patents are listed for that product.
- Whether the applicant certifies Paragraph III or Paragraph IV.
- Whether the patent owner files an infringement action within the statutory period.
- Whether a 30-month stay applies.
- Whether the proposed label induces use covered by the method claims.
The patent record and FDA Orange Book must be reviewed together. The number 8,916,588 alone does not establish current listing status, unexpired claim scope or the existence of a pending Paragraph IV dispute.
Which companies and products are relevant?
The principal competitive comparison is with other methylphenidate delivery systems.
| Product category |
Typical release profile |
Relationship to the patent |
| Immediate-release methylphenidate |
Rapid onset and shorter duration |
Usually outside the delayed-release limitations |
| Conventional extended-release methylphenidate |
Earlier release with prolonged exposure |
May fail the five-hour lag and 12-19-hour Tmax limitations |
| Delayed-release evening methylphenidate |
Minimal overnight exposure and morning onset |
Closest technical risk category |
| Transdermal methylphenidate |
Nonoral delivery |
Generally outside oral formulation claims |
| Long-acting bead products |
Multiparticulate release |
Risk depends on coating, pharmacokinetics and timing |
The closest commercial comparator is an evening-dosed delayed-release and extended-release methylphenidate product. Products using different polymers or release mechanisms may still encounter the broad pharmacokinetic claims if they reproduce the claimed profile.
What patent litigation and settlement issues matter?
A complete litigation assessment requires current court-docket and Orange Book data. The claim text alone does not establish whether US Patent 8,916,588 has been asserted, challenged, licensed or settled.
For diligence, the highest-value litigation questions are:
- Whether the patent has been asserted against an ANDA applicant.
- Whether a Paragraph IV notice was served.
- Whether a 30-month stay was triggered.
- Whether the patent was upheld, narrowed or invalidated.
- Whether a settlement permits an agreed generic launch date.
- Whether a covenant not to sue or license covers only the patent or the broader formulation platform.
- Whether continuation patents cover the same commercial product.
Patent-family analysis is important because a continuation may preserve overlapping formulation, pharmacokinetic or method-of-use protection after a parent patent becomes unenforceable or expires.
What geographic protection exists?
US Patent 8,916,588 provides protection only in the United States. Foreign counterparts, if any, must be assessed separately by jurisdiction.
The relevant geographic risks include:
- European patent protection and national validation.
- Canadian formulation and method claims.
- Japanese and Australian delayed-release patents.
- Patent term adjustments or extensions.
- Foreign opposition, revocation or limitation proceedings.
- Different treatment of medical-use claims.
A US freedom-to-operate opinion cannot be extended to Europe, Canada or other markets without reviewing the relevant national patent families.
Key Takeaways
- US Patent 8,916,588 protects delayed-release and sustained-release methylphenidate treatment methods.
- Its core commercial concept is evening administration, minimal overnight exposure and therapeutic methylphenidate levels after awakening.
- The principal quantitative limitations are a five-hour minimum lag, AUC0-10 below approximately 7% of AUC0-48 and Tmax between 12 and 19 hours.
- Claim 24 provides the clearest structural coverage of multiparticulate beads, specific coating materials and a water-soluble capsule.
- Claims 1 and 17 are broader in formulation architecture but more dependent on pharmacokinetic proof.
- Design-around options include changing the release mechanism, coating composition, Tmax, AUC profile, dissolution profile or dosage form.
- FDA approval and Orange Book listing must be analyzed separately from validity and infringement.
- The supplied claim text does not establish current expiration, Orange Book listing, Paragraph IV activity, litigation status, settlement terms or licensing arrangements.
FAQs
Does US Patent 8,916,588 cover all extended-release methylphenidate products?
No. The claims require a delayed-release profile and, in several claims, particular formulation architecture, dissolution performance or pharmacokinetic parameters.
Can a generic avoid the patent by using a different methylphenidate salt?
Not necessarily. The claims expressly cover methylphenidate and a pharmaceutical salt thereof. A different salt may avoid other formulation limitations, but it does not automatically avoid the patent.
Does a product need to be administered at night to infringe claim 1?
Claim 1 does not expressly require nighttime administration. Claims 7 and 11 add sleep-related or nighttime limitations. A product administered at night is more likely to implicate those dependent claims.
Are the coating ingredients in claim 24 required in every claim?
No. The exact ethyl cellulose, hydroxypropyl cellulose, dibutyl sebacate, magnesium stearate and methacrylic acid copolymer requirements are concentrated in narrower claims, especially claim 24 and its related dependent claims.
Does a Paragraph IV certification invalidate US Patent 8,916,588?
No. A Paragraph IV certification is an applicant’s position that the patent is invalid, unenforceable or not infringed. The patent remains enforceable unless it expires, is disclaimed, is judicially invalidated or otherwise loses enforceability.
References
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United States Patent and Trademark Office. (2014). United States Patent No. 8,916,588. https://patents.google.com/patent/US8916588B2/en
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U.S. Food and Drug Administration. (2024). 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
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U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Patent and exclusivity information. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
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U.S. Food and Drug Administration. (2024). Abbreviated new drug application regulations and patent certifications. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-D/part-314
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U.S. Patent and Trademark Office. (2024). Manual of Patent Examining Procedure, patent term adjustment and patent term extension. https://www.uspto.gov/web/offices/pac/mpep/index.htm
