US Patent 11,253,472: Dronabinol Oral Solution Claims, Patent Scope, Exclusivity and Generic Entry Risk

US Patent 11,253,472 covers a stable oral dronabinol solution defined primarily by four formulation parameters: dronabinol concentration, water content, alcohol content, and a propylene glycol or polyethylene glycol co-solvent, together with an antioxidant. The independent claim is composition-based and does not require a particular brand, indication, container, dosing regimen, or manufacturing process. A competing product can avoid literal infringement by moving outside the claimed concentration ranges or by using a materially different solvent system, although the doctrine of equivalents may remain relevant.

What does US Patent 11,253,472 claim?

The patent’s central claim is claim 1. It covers:

Claim element	Claimed range or requirement
Dosage form	Stable oral pharmaceutical solution
Active ingredient	Dronabinol
Dronabinol concentration	About 0.1% to about 5% w/w
Water	31.90% w/w or less
Alcohol	About 15% to about 90% w/w
Co-solvent	About 17.5% w/w or more
Co-solvent identity	Propylene glycol, polyethylene glycol, or a mixture
Other required component	An antioxidant
Measurement basis	Weight by total weight of solution

The claim does not specify a particular alcohol. Depending on the specification and prosecution history, "alcohol" could encompass ethanol and potentially other pharmaceutically acceptable alcohols. For infringement analysis, the patent’s claim construction, specification, prosecution statements, and any relevant court interpretation would control.

The claim also does not state a maximum amount for the co-solvent. Its practical upper limit is imposed by the requirement that all formulation components collectively equal 100% w/w and by the claimed ranges for dronabinol, water, alcohol, and other ingredients.

How do claims 2 and 3 narrow claim 1?

Claims 2 and 3 narrow only the alcohol concentration.

Claim	Alcohol range	Relationship to claim 1
Claim 1	About 15% to about 90% w/w	Broadest alcohol range
Claim 2	About 40% to about 90% w/w	Narrows the lower bound
Claim 3	About 15% to about 65% w/w	Narrows the upper bound

Claims 2 and 3 overlap from approximately 40% to 65% w/w alcohol. A formulation within that overlap may satisfy both dependent claims if it also meets every other limitation of claim 1.

The dependent claims do not create separate protection for a different active ingredient, dosage form, indication, or delivery device. They are concentration-specific fallback positions within the same oral-solution formulation concept.

What formulation space does claim 1 cover?

Claim 1 covers a wide but technically constrained formulation space.

Dronabinol concentration

The claimed range is approximately 0.1% to 5% w/w. At a nominal density close to 1 g/mL, that range roughly corresponds to 1 to 50 mg/mL, although actual mg/mL conversion depends on formulation density.

A product containing 10 mg/mL dronabinol would generally fall within the numerical range. A product containing more than about 5% w/w or less than about 0.1% w/w could avoid literal infringement of this limitation, subject to the interpretation of "about" and the doctrine of equivalents.

Water limitation

The water ceiling is 31.90% w/w or less. This is an express upper-bound limitation. A formulation containing 32% water may present a non-infringement position, but the outcome would depend on analytical precision, rounding conventions, the meaning of "31.90% or less," and whether the product is materially equivalent to the claimed formulation.

The water limitation is commercially important because aqueous content can affect cannabinoid solubility, physical stability, microbial control, preservative performance, and taste.

Alcohol limitation

The broad claim covers approximately 15% to 90% w/w alcohol. Claims 2 and 3 divide that space into higher-alcohol and lower-to-intermediate-alcohol embodiments.

The broad alcohol range creates substantial claim overlap with many hydroalcoholic oral solutions. A product using ethanol at 20%, 50%, or 80% w/w would fall within the numerical alcohol range, assuming the other limitations are met.

Co-solvent limitation

The formulation must contain at least approximately 17.5% w/w of propylene glycol, polyethylene glycol, or a mixture of the two. The co-solvent requirement is a major design-around boundary.

A formulation using glycerol, a medium-chain triglyceride, a lipid vehicle, or another solubilizer instead of propylene glycol or polyethylene glycol may avoid literal infringement of this limitation. Whether such a formulation is equivalent would depend on the technical function, interchangeability, prosecution history, and claim construction.

Antioxidant requirement

Claim 1 requires an antioxidant but does not provide a concentration range in the quoted claim. The antioxidant must therefore be present in the claimed solution, and the product must satisfy the relevant construction of "antioxidant."

Potential antioxidant categories may include tocopherols, ascorbic acid or derivatives, sulfites, and other oxidation-control agents, depending on the patent specification. The exact identity and concentration should be assessed against the patent’s written description and examples.

What is the strongest infringement theory under US Patent 11,253,472?

The strongest literal infringement case would involve an oral dronabinol solution with the following profile:

0.1% to 5% w/w dronabinol;
no more than 31.90% w/w water;
15% to 90% w/w alcohol;
at least approximately 17.5% w/w propylene glycol, polyethylene glycol, or both; and
an antioxidant.

A product does not need to copy the commercial product’s brand name, label, flavor, bottle, dose, or indication to infringe a composition claim. The relevant question is whether the accused product contains every required claim element, either literally or under an applicable equivalents analysis.

A formulation outside one limitation can defeat literal infringement. The most commercially practical escape routes are likely:

Use no alcohol or less than approximately 15% alcohol.
Use more than 31.90% water.
Use less than approximately 17.5% propylene glycol and polyethylene glycol combined.
Replace the claimed co-solvent with a different solvent system.
Use a non-solution dosage form, such as a suspension, capsule, tablet, or lipid dispersion.
Use a dronabinol concentration outside the claimed range.

Each route can create separate formulation, stability, palatability, manufacturing, or regulatory problems.

What are the main design-around options?

Design-around strategy	Literal infringement risk	Technical or regulatory tradeoff
Replace propylene glycol and polyethylene glycol	Lower if no equivalent solvent is used	May reduce dronabinol solubility or stability
Reduce co-solvent below 17.5%	Lower	May cause precipitation or dose-uniformity issues
Increase water above 31.90%	Lower	May impair cannabinoid solubility and physical stability
Reduce alcohol below 15%	Lower	May require a different solubilization system
Eliminate alcohol	Lower	May require surfactants, lipids, or complexation
Use a capsule or tablet	Outside oral-solution claim	Different bioavailability and formulation profile
Use a suspension instead of a solution	Potentially outside claim	Dose uniformity and sedimentation risks
Change dronabinol concentration	Lower if clearly outside range	May require a different dose volume or label
Use a different antioxidant	Does not avoid the claim if all other elements remain present	Antioxidant identity may affect stability and sensory profile

The most defensible design-around is generally one that changes the formulation architecture rather than merely moving a concentration by a narrow margin. A small numerical adjustment can invite an equivalents argument, particularly where the change produces the same function in substantially the same way.

How strong is the patent estate represented by this patent?

US 11,253,472 appears to be technically focused on formulation composition rather than broad cannabinoid use. Its strength depends on four factors:

Strength factor	Assessment
Claim breadth	Moderate to broad within hydroalcoholic oral solutions
Chemical specificity	Moderate, because the co-solvent class is expressly limited
Design-around exposure	Meaningful, especially through solvent substitution
Product-readthrough potential	Potentially high for dronabinol oral solutions using ethanol and glycol co-solvents

The claim is stronger against products that reproduce the same solvent architecture than against products using a different delivery platform. It is less likely to block all oral dronabinol products because it does not expressly cover capsules, tablets, emulsions, suspensions, transdermal systems, inhaled products, or every possible oral liquid.

The use of "about" expands practical scope but also introduces boundary questions. Courts commonly interpret "about" in light of the intrinsic record, analytical precision, and the technology. It does not create an unlimited range.

What patents protect dronabinol products beyond this formulation patent?

The dronabinol patent landscape generally divides into five categories:

Active-ingredient and synthetic cannabinoid patents

Older patents covering dronabinol or synthetic tetrahydrocannabinol chemistry may have expired or may provide limited current exclusionary value. Dronabinol itself is an established active pharmaceutical ingredient, which reduces the likelihood that a new product can obtain broad composition-of-matter protection over the molecule.

Oral dosage-form patents

These patents may cover capsules, solutions, suspensions, or other dosage forms. The relevant claims can address excipients, dissolution, stability, dose uniformity, taste masking, or bioavailability.

Formulation and stability patents

US 11,253,472 falls principally into this category. These patents can remain commercially relevant after active-ingredient patents expire because they target a specific product architecture.

Method-of-use patents

Method claims may cover treatment of AIDS-related anorexia, chemotherapy-associated nausea and vomiting, appetite stimulation, or other therapeutic uses. Their value depends on FDA-approved labeling, claim scope, remaining patent term, and the ability to enforce a labeled-use theory against a generic product.

Manufacturing and analytical patents

These patents may cover mixing order, oxygen control, antioxidant selection, filling, packaging, impurity control, or testing methods. They can create manufacturing barriers even where a competitor avoids the core formulation claims.

What is the Orange Book status of US Patent 11,253,472?

The Orange Book status must be determined from the current FDA publication and the drug-specific patent listing for the relevant dronabinol product. A patent number alone does not establish that a patent is listed in the Orange Book.

The key distinctions are:

Issue	Commercial significance
Listed in the Orange Book	Can support a Paragraph IV certification and statutory notice process
Not listed in the Orange Book	May still be enforceable, but generally does not create the same ANDA certification pathway
Listed as formulation patent	May delay approval if timely litigation produces a 30-month stay
Listed as method-of-use patent	A section viii statement or carve-out may be available depending on the use claim
Patent expired or delisted	Does not create a current Orange Book block

FDA Orange Book listings should be checked against the exact reference product, dosage form, strength, and patent-use code. The relevant source is the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations and its electronic Orange Book database.[1]

When does exclusivity for dronabinol oral solution end?

FDA regulatory exclusivity and patent exclusivity are separate rights.

Syndros, the dronabinol oral solution marketed by Insys Therapeutics, received FDA approval in 2016. The product’s regulatory protection may include new chemical entity, orphan-drug, pediatric, or other exclusivity depending on the specific approval and indication. Regulatory exclusivity periods do not necessarily run for the same duration as US Patent 11,253,472.

Protection	Governing source	Effect
NCE exclusivity	FDCA section 505(j)	Generally blocks certain ANDA approvals for five years
Orphan-drug exclusivity	FDCA section 527	Generally blocks approval of the same drug for the same indication for seven years
Patent term	35 U.S.C. § 154	Depends on earliest effective nonprovisional filing date, adjustments, and disclaimers
Patent-term extension	35 U.S.C. § 156	May extend an eligible patent for regulatory review time
Pediatric exclusivity	FDCA section 505A	Can add six months to qualifying protections

The patent expiration date cannot be reliably calculated from the issued claims alone. It requires the patent’s priority chain, earliest effective nonprovisional filing date, patent-term adjustment, terminal disclaimers, and any patent-term extension. The governing statutory framework is 35 U.S.C. §§ 154 and 156.[2]

Are Paragraph IV challenges likely against this patent?

A Paragraph IV challenge would be relevant only if the patent is listed in the Orange Book for the applicable reference product. An ANDA applicant could certify that the patent is invalid, unenforceable, or will not be infringed by the proposed product.

For this claim set, likely Paragraph IV positions would include:

lack of written description or enablement for the full formulation range;
indefiniteness of "about";
indefiniteness or claim-construction disputes involving "stable";
anticipation by an earlier dronabinol oral solution;
obviousness based on known hydroalcoholic cannabinoid formulations;
non-infringement based on water, alcohol, co-solvent, or dronabinol concentration;
absence of a qualifying antioxidant;
use of a different solvent system.

The claim’s vulnerability will depend heavily on the patent’s examples and prosecution history. A broad numerical claim supported by only a narrow set of examples may face enablement or written-description scrutiny. Conversely, extensive stability data across the claimed ranges can materially strengthen the patent.

What patent litigation or settlement risk affects generic entry?

A timely Paragraph IV notice can trigger patent litigation by the listed patent owner or NDA holder. Under FDCA section 505(j)(5)(B)(iii), an action filed within the statutory period can result in a 30-month stay of ANDA approval, subject to statutory exceptions and court developments.[3]

Potential litigation outcomes include:

Outcome	Effect on entry
Patent upheld and infringed	Generic entry remains blocked until expiration or settlement
Patent invalidated	ANDA approval can proceed, subject to other listed patents and exclusivity
Non-infringement judgment	Proposed product may launch if no other barrier applies
Settlement with later entry date	Entry occurs on agreed terms
Product redesign	Applicant may remove the accused formulation features
Label carve-out	May reduce method-of-use exposure but does not avoid composition claims

A composition claim such as claim 1 is generally harder to avoid through a label carve-out than a method-of-use claim. If the product itself falls within the claim, the indication on the label does not remove composition infringement.

No litigation or settlement conclusion should be inferred solely from the patent number. Court dockets, FDA listing records, and the patent owner’s filings must be reviewed separately.

How does this patent compare with Marinol and other dronabinol products?

Product or platform	Dosage form	Primary patent exposure
Marinol	Oral capsule	Capsule formulation, use, and historical dronabinol patents
Syndros	Oral solution	Solution formulation, stability, use, and listed-product patents
Generic dronabinol capsules	Oral capsule	Capsule-specific Orange Book patents and exclusivity
Competing oral solution	Oral solution	US 11,253,472 and related solution patents
Non-solution liquid	Suspension, emulsion, or dispersion	Potentially outside claim 1, subject to construction
Compounded product	Pharmacy-compounded oral preparation	Different regulatory and patent analysis

US 11,253,472 is most commercially relevant to an ANDA or 505(b)(2) applicant pursuing a dronabinol oral solution that uses alcohol plus propylene glycol or polyethylene glycol. It is less directly relevant to a capsule applicant or to a product built on a non-solution vehicle.

What manufacturing and IP barriers remain after patent expiration?

A competitor may still face technical barriers after the patent expires:

dronabinol oxidation and degradation;
precipitation during storage;
dose uniformity at low concentration;
ethanol evaporation and fill-volume variation;
container-closure compatibility;
extractables and leachables;
microbial control in the aqueous phase;
antioxidant stability;
taste and patient acceptability;
scale-up and reproducibility;
analytical validation of impurities and potency.

These issues can support trade-secret protection even where the patent no longer blocks entry. Manufacturing know-how may also affect the ability of a generic or 505(b)(2) applicant to reproduce the reference product’s stability profile.

Key Takeaways

US 11,253,472 claims a stable oral dronabinol solution, not dronabinol generally.
Claim 1 requires 0.1% to 5% w/w dronabinol, no more than 31.90% water, 15% to 90% alcohol, at least about 17.5% propylene glycol or polyethylene glycol, and an antioxidant.
Claim 2 covers 40% to 90% alcohol; claim 3 covers 15% to 65%.
Claims 2 and 3 overlap from approximately 40% to 65% alcohol.
The main design-around routes are solvent substitution, lower co-solvent content, higher water content, reduced or absent alcohol, and conversion to a non-solution dosage form.
The patent is potentially strong against hydroalcoholic dronabinol solutions that use glycol co-solvents.
The patent does not, on its face, block dronabinol capsules, tablets, suspensions, or every oral liquid.
Orange Book listing, patent-term calculation, Paragraph IV exposure, and litigation risk require review of the current FDA and USPTO records rather than the claim text alone.
Composition claims are less amenable to label carve-outs than method-of-use claims.
Stability, oxidation control, dose uniformity, and manufacturing reproducibility remain relevant commercial barriers even where a competitor designs around the issued claims.

FAQs About US Patent 11,253,472

Does US Patent 11,253,472 cover Syndros?

It is directed to the same general product category as Syndros: a stable oral dronabinol solution. Whether it covers the marketed product depends on the product’s actual formulation and the patent’s claim scope, prosecution history, and any applicable Orange Book listing.

Can a generic avoid the patent by using ethanol without propylene glycol?

Potentially. Claim 1 requires at least approximately 17.5% w/w of propylene glycol, polyethylene glycol, or a mixture. An ethanol-only formulation may avoid literal infringement, although the doctrine of equivalents and other patents must be assessed.

Does claim 3 cover a formulation with 70% alcohol?

No, not under its stated numerical range. Claim 3 is limited to approximately 15% to 65% w/w alcohol. A 70% alcohol formulation may still fall within claim 1, which extends to approximately 90%.

Does the patent cover a dronabinol suspension?

Not literally based on the quoted claims. Claim 1 requires a pharmaceutical solution. A suspension could raise infringement issues only if it is legally and technically characterized as the claimed solution or is equivalent to it.

Is a Paragraph IV certification possible against this patent?

Yes, if the patent is listed in the Orange Book for the relevant reference product and remains an applicable listed patent. The applicant could challenge validity, enforceability, or infringement, subject to the FDCA’s ANDA certification and notice requirements.

References

U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book
U.S. Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension. https://www.uspto.gov/patents/laws/patent-term-calculator
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j).
Patent Act, 35 U.S.C. §§ 154, 156.
U.S. Patent No. 11,253,472. (2022). United States Patent and Trademark Office.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Wellhouse Pharma	SYNDROS	dronabinol	SOLUTION;ORAL	205525-001	Mar 23, 2017		DISCN	Yes	No	11,253,472	⤷ Start Trial	Y	Y			⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Details for Patent: 11,253,472

Which drugs does patent 11,253,472 protect, and when does it expire?

Summary for Patent: 11,253,472