United States Patent 11,278,623: Lidocaine Non-Aqueous Patch Claims, Exclusivity and Patent Landscape

U.S. Patent No. 11,278,623 protects a method of treating pain with a non-aqueous lidocaine plaster containing dipropylene glycol, isostearic acid, and an elastomeric adhesive matrix. The independent claim is composition-specific and requires a narrow isostearic-acid range of 1.4% to 2.1% by mass. Dependent claims add adhesive composition, drug loading, total dose, delivery performance, backing materials, post-herpetic neuralgia and a treatment duration of up to 12 hours.

The claims are directed to use of a patch, not to every lidocaine patch. A competing product must satisfy each limitation of claim 1, either literally or under the doctrine of equivalents, before the dependent claims become relevant.

What does U.S. Patent 11,278,623 cover?

The patent covers a method of treating pain by applying a specified non-aqueous lidocaine plaster to skin. Claim 1 requires all of the following:

Required element	Claim limitation
Therapeutic method	Treating pain in an individual in need
Delivery system	Applying a non-aqueous patch to skin
Dosage form	A plaster
Active ingredient	Lidocaine
Dissolving agent	Dipropylene glycol and isostearic acid
Lidocaine concentration	0.5% to 7% by mass
Total dissolving agent	1.435% to 9.1% by mass
Isostearic acid	1.4% to 2.1% by mass
Matrix component	An elastomer

The claim does not cover a lidocaine patch merely because it is non-aqueous. The patch must contain the specified dissolving-agent system and must fall within the claimed composition ranges.

The independent claim also requires a method of treatment. A composition or patch sold without a method-of-use theory may raise a different infringement analysis from a product that is labeled, promoted or instructed for the claimed treatment.

How narrow is claim 1 of U.S. Patent 11,278,623?

Claim 1 is narrower than a general lidocaine transdermal-patch claim because it combines several quantitative limitations.

The most important limitation is the isostearic-acid range of 1.4% to 2.1% by mass. A competing formulation containing 1.39% isostearic acid may fall outside the literal range, subject to measurement methodology, claim construction and possible equivalents analysis. A formulation containing 2.10% isostearic acid is within the ordinary numerical meaning of the range.

The claim also requires:

Lidocaine between 0.5% and 7% by mass.
Dissolving agent between 1.435% and 9.1% by mass.
Dipropylene glycol and isostearic acid as components of the dissolving agent.
An elastomer in the plaster.
Application to a person for treating pain.

The ranges are cumulative. Satisfying the lidocaine range alone is insufficient.

Does claim 1 require a particular elastomer?

No. Claim 1 requires an elastomer but does not specify its identity. Claim 2 narrows the elastomer to polyisobutylene and styrene-isoprene rubber.

This distinction matters in freedom-to-operate work. A formulation using a different elastomer may avoid claim 2 but still infringe claim 1 if the alternative elastomer meets the broader claim construction.

What happens when multiple ingredients are present?

Claim 1 does not expressly exclude additional ingredients. Claims 5, 13 and 14 expressly contemplate additional resins and liquid paraffin. The presence of a tackifier, mineral oil or another excipient does not automatically avoid the claims.

A formulation that contains additional adhesive components can still fall within claim 1 if it retains the required lidocaine, dipropylene-glycol, isostearic-acid and elastomer limitations.

What do the dependent claims add?

Claims	Added limitation	Commercial or technical significance
2	Elastomer consists of polyisobutylene and styrene-isoprene rubber	Narrows the adhesive matrix
3	Elastomer is 10% to 40% by mass	Defines a broad matrix-loading range
4	Elastomer is 20% to 40% by mass	Narrower adhesive-loading range
5	Further comprises terpene resin	Adds tack and matrix-control component
6	After 12 hours, 80% or less of lidocaine remains	Requires at least 20% depletion from the patch
7	Total lidocaine is 196 mg or less	Limits total drug content
8	Lidocaine is 0.1 to 1 mg/cm²	Defines areal drug loading
9	Lidocaine is completely dissolved in the dissolving agent	Addresses drug solubilization
10	Lidocaine is completely dissolved in the plaster	Addresses the final matrix state
11	Plaster mass is about 60 to 200 g/m²	Defines coating weight
12	Plaster mass is 80 to 180 g/m²	Narrower coating-weight range
13	Specified tackifier resins	Covers terpene, rosin, petroleum and phenolic systems
14	Liquid paraffin	Adds a plasticizing or emollient component
15	Specified textile substrates	Covers woven, knitted and nonwoven backings
16	Polyester woven fabric	Narrow backing limitation
17	Pain is post-herpetic neuralgia	Narrows the indication
18	Application for up to and including 12 hours	Defines a maximum wear period

Claims 3 and 4 are nested. Any product satisfying claim 4 also satisfies claim 3, assuming all limitations of claim 1 are met.

Claims 9 and 10 overlap conceptually but address different locations in the formulation. Claim 9 focuses on dissolution in the dissolving agent. Claim 10 focuses on complete dissolution in the plaster. Analytical testing, microscopy, extraction procedures and the meaning of “completely dissolved” could become important in litigation.

What formulation is most exposed to the patent?

The highest-risk formulation is a lidocaine adhesive matrix with the following profile:

Non-aqueous patch.
Lidocaine within 0.5% to 7% by mass.
Dipropylene glycol and isostearic acid.
Isostearic acid at 1.4% to 2.1%.
Polyisobutylene and styrene-isoprene rubber.
Terpene resin or another listed tackifier.
Liquid paraffin.
Polyester woven backing.
12-hour wear period.
Lidocaine loading within 0.1 to 1 mg/cm².

That profile closely tracks the architecture of commercial non-aqueous lidocaine systems, including products marketed for localized neuropathic pain. A product with a different adhesive matrix, a different solvent system, or isostearic acid outside the claimed range presents a stronger design-around position.

Is the patent directed to ZTlido or Lidoderm?

The formulation language is closely aligned with the type of non-aqueous lidocaine system used in ZTlido, including an adhesive matrix based on elastomers, dipropylene glycol, isostearic acid and tackifying components. ZTlido is an FDA-approved 1.8% lidocaine topical system indicated for relief of neuropathic pain associated with post-herpetic neuralgia.[1]

Lidoderm has a different formulation profile. Lidoderm is a 5% lidocaine patch with an aqueous adhesive system and is historically associated with a different patent and regulatory product profile.[2] The existence of a patent covering a non-aqueous matrix does not automatically establish coverage of every Lidoderm generic.

Product or category	General formulation profile	Relevance to U.S. 11,278,623
ZTlido	Non-aqueous 1.8% lidocaine topical system	High technical overlap potential
Lidoderm	5% lidocaine patch with different adhesive architecture	Overlap depends on exact formulation
Generic Lidoderm	ANDA products referencing Lidoderm	Usually assessed against the reference formulation and listed patents
Compounded lidocaine patch	Variable formulation and labeling	Risk depends on composition and inducement facts
Future 505(b)(2) product	May use a modified delivery system	Patent risk depends on formulation and label

The patent claims do not require a 1.8% lidocaine concentration. A product at 1.8% can fall within the 0.5% to 7% range, but concentration alone is not sufficient to establish infringement.

What is the Orange Book status of U.S. Patent 11,278,623?

The relevant FDA question is whether U.S. Patent 11,278,623 is listed in the Orange Book against an approved lidocaine topical system and whether the listing covers an active ingredient, formulation, or method of use.[3]

For a patent of this type, the likely listing category is a formulation or method-of-use patent rather than a basic compound patent. The patent does not claim the lidocaine molecule itself. Its commercial value therefore depends on:

The approved product associated with the listing.
The patent-use code, if any.
Whether the FDA accepts the patent as properly listed.
Whether an ANDA applicant must address the patent with a Paragraph IV certification.
Whether the approved product has remaining regulatory exclusivity.

Orange Book listing does not determine ultimate patent validity or infringement. It creates a regulatory pathway for a patent challenge and can delay approval of an ANDA under the Hatch-Waxman framework.

When does U.S. Patent 11,278,623 expire?

The patent issued on March 22, 2022. Its enforceable term depends on the earliest effective nonprovisional filing date, any applicable priority claims, patent-term adjustment, terminal disclaimers and patent-term extension calculations.[4]

The expiration date cannot be reliably calculated from the issued claims alone. A patent-family review must examine the front page, continuity data, maintenance records and any terminal disclaimer in USPTO Patent Center. The issue date is not the patent expiration date.

The commercial exclusivity timeline should be separated into four dates:

Event	Legal significance
Earliest effective nonprovisional filing	Usually controls the 20-year patent term
Grant date	Starts enforceable patent rights, subject to the statutory term
FDA approval date	Controls regulatory exclusivity and Orange Book linkage
Patent expiration date	Determines the end of ordinary patent enforcement

Any freedom-to-operate opinion should use the USPTO term calculation rather than an expiration estimate derived only from the patent number.

What Paragraph IV challenges could target this patent?

An ANDA applicant seeking approval for a product that references an associated lidocaine patch may submit a Paragraph IV certification if it contends that the patent is invalid, unenforceable or not infringed.[5]

Potential Paragraph IV positions include:

Non-infringement

A generic applicant could argue that its product does not contain:

Isostearic acid within 1.4% to 2.1%.
Dipropylene glycol.
The claimed elastomer.
A plaster with the required combined composition.
A labeled method of treating pain that induces infringement.

The strongest non-infringement position would generally involve a formulation outside the isostearic-acid range and a label that does not encourage the patented method.

Invalidity for lack of novelty

Prior art could challenge the combination of lidocaine, dipropylene glycol, isostearic acid and an elastomeric plaster. The prior art would need to disclose every limitation of claim 1 in a single reference for a direct anticipation theory.

Invalidity for obviousness

An obviousness challenge could combine references concerning:

Lidocaine adhesive matrices.
Dipropylene glycol as a solvent.
Isostearic acid as a solubilizer or penetration enhancer.
Polyisobutylene and styrene-isoprene rubber adhesives.
Twelve-hour transdermal delivery.

The narrow numerical ranges may become central. A challenger would need evidence that the claimed ranges were selected predictably, disclosed in the prior art or obvious to optimize.

Written description and enablement

Claims 9 and 10 may attract scrutiny because “completely dissolved” can require objective analytical support. The specification would need to support the full claimed concentration ranges and the broad set of adhesive, resin and backing combinations.

What patent litigation affects the patent?

The principal litigation risk is a Hatch-Waxman action following a Paragraph IV certification by an ANDA applicant. A patent owner generally has 45 days after receiving a Paragraph IV notice to file suit. A timely suit can trigger a statutory stay of FDA approval for up to 30 months, subject to statutory exceptions and court action.[5]

Other litigation theories include:

Induced infringement based on the generic label.
Contributory infringement involving sale of a formulation designed for the patented use.
Direct infringement by use of the patch.
Declaratory-judgment litigation before commercial launch.
Post-grant review or inter partes review before the Patent Trial and Appeal Board.
Patent-term or Orange Book listing disputes.

The claims are method claims, so label language and promotional conduct can be as important as the physical product. A generic label that recommends treatment of post-herpetic neuralgia for up to 12 hours would create greater exposure than a label omitting the patented indication, although omission does not eliminate all infringement theories.

How strong is the patent estate?

The focal patent has meaningful but concentrated protection.

Strengths

It claims a commercially practical non-aqueous lidocaine matrix.
It combines ingredient identity and quantitative ranges.
Isostearic acid is limited to a relatively narrow range.
The dependent claims cover common adhesive, backing and wear-time characteristics.
The post-herpetic-neuralgia claim aligns with an FDA-recognized indication.
Claims 6, 9 and 10 provide performance and formulation positions beyond simple ingredient listing.

Weaknesses

The patent does not claim lidocaine generally.
It does not claim every non-aqueous patch.
A competitor may design around the isostearic-acid range.
The method format may complicate enforcement against a product with a carefully drafted label.
Several limitations require laboratory testing or assessment of formulation state.
Prior art in lidocaine patches and pressure-sensitive adhesives is extensive.

The estate is strongest when supported by continuation patents covering the product, formulation, manufacturing process and method of use separately. One issued method patent is less robust than a coordinated family with unexpired formulation and product claims.

What manufacturing and intellectual-property barriers remain?

Manufacturing design-around is technically feasible but may affect product performance. Changing isostearic acid, solvent content or elastomer ratio can alter:

Lidocaine solubility.
Adhesive tack.
Peel strength.
Skin irritation.
Drug release.
Residual drug after 12 hours.
Stability during storage.
Coating uniformity.
Backing compatibility.

A non-infringing formulation may still require substantial clinical and regulatory work. FDA approval of a generic or alternative lidocaine patch depends on the applicable pathway, product sameness, bioequivalence or comparative clinical evidence, manufacturing controls and labeling.[1,6]

The patent does not appear to create a biologic-style manufacturing barrier. Lidocaine is a small molecule, and the principal technical barrier is formulation reproducibility rather than cell-line, sequence or biologic-process control.

How does this patent compare with generic Lidoderm patent risk?

Generic Lidoderm risk is generally assessed against Lidoderm’s listed patents and the exact ANDA formulation, not against every later patent involving lidocaine patches. A generic Lidoderm product may avoid U.S. 11,278,623 if it does not contain the claimed non-aqueous adhesive system.

By contrast, a generic or follow-on product designed to replicate a non-aqueous 12-hour lidocaine system presents greater risk because the formulation may include the same classes of solvents, elastomers, tackifiers and backing materials.

Issue	Generic Lidoderm	Non-aqueous 12-hour lidocaine system
Primary regulatory reference	Lidoderm	Relevant approved non-aqueous product
Likely formulation	Aqueous or different matrix	Elastomeric adhesive matrix
Risk under Patent 11,278,623	Product-specific	Potentially high if composition overlaps
Main design-around lever	Change formulation	Move outside isostearic-acid or solvent limits
Method-of-use exposure	Depends on label	Higher if PHN and 12-hour use are promoted

What is the generic launch risk?

A generic launch risk assessment should use three scenarios:

At-risk launch

The applicant launches before final patent resolution after a Paragraph IV certification. This creates potential damages, injunctive relief and commercial disruption if the patent survives and is found infringed.

Delayed launch

The applicant settles or waits for patent expiration. The settlement may include a permitted entry date, manufacturing license, authorized-generic arrangement or other commercial terms.

Design-around launch

The applicant changes one or more composition variables, such as isostearic acid, dipropylene glycol, elastomer type or backing material. This reduces literal infringement risk but may require new development and regulatory work.

Revenue exposure is concentrated in the branded non-aqueous lidocaine product and any licensed product that depends on the same formulation. The patent’s economic value is lower for conventional 5% lidocaine patches that do not practice the claimed matrix.

Key Takeaways

U.S. Patent 11,278,623 is a method patent for treating pain with a defined non-aqueous lidocaine plaster.
Claim 1 requires dipropylene glycol, isostearic acid at 1.4% to 2.1%, lidocaine at 0.5% to 7% and an elastomer.
Claims 2 through 18 add adhesive identity, resin, dose, loading, dissolution, coating weight, backing, indication and wear-time limitations.
The claim architecture has close technical relevance to non-aqueous 12-hour lidocaine systems such as ZTlido.
Conventional Lidoderm generics are not automatically within the patent’s scope.
The principal design-around opportunity is changing the isostearic-acid range or solvent and elastomer system.
Paragraph IV exposure depends on the approved product, Orange Book listing, patent-use code, ANDA formulation and generic label.
The patent’s expiration date requires review of USPTO continuity, terminal-disclaimer and patent-term records.
The patent is a small-molecule formulation and method-of-use asset, not a biologic patent.
Commercial strength depends on related continuation patents and any separate formulation or manufacturing claims.

Frequently Asked Questions

Does U.S. Patent 11,278,623 cover a 5% lidocaine patch?

Not automatically. A 5% patch satisfies the lidocaine concentration range, but it must also contain the claimed non-aqueous plaster, dipropylene glycol, isostearic acid within 1.4% to 2.1% and an elastomer.

Can a lidocaine patch avoid the patent by using water?

Potentially. Claim 1 requires a non-aqueous patch. A genuinely aqueous system may avoid that limitation, although the formulation must be characterized under the patent’s claim construction.

Does the patent cover a patch worn for more than 12 hours?

Claim 18 covers application for up to and including 12 hours. A longer wear period does not necessarily avoid claim 1, but it would not satisfy claim 18 unless the product is also used for 12 hours or less.

Is a product with 1.8% lidocaine automatically infringing?

No. The 1.8% concentration falls within the claimed lidocaine range, but infringement requires every limitation of claim 1 or the relevant dependent claim.

Can a company avoid claim 2 while remaining exposed under claim 1?

Yes. A formulation using an elastomer other than polyisobutylene and styrene-isoprene rubber may avoid claim 2 while still satisfying the broader elastomer requirement in claim 1.

References

U.S. Food and Drug Administration. (n.d.). ZTlido (lidocaine topical system) prescribing information. FDA. https://www.accessdata.fda.gov
U.S. Food and Drug Administration. (n.d.). Lidoderm (lidocaine patch 5%) prescribing information. FDA. https://www.accessdata.fda.gov
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. FDA. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book
United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term information. USPTO. https://www.uspto.gov/patents/laws/patent-term-adjustment
21 U.S.C. § 355(j). Abbreviated applications for new drugs.
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application process. FDA. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Scilex Pharms	ZTLIDO	lidocaine	PATCH;TOPICAL	207962-001	Feb 28, 2018	AB	RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial	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

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Brazil	112013028802	⤷ Start Trial
Brazil	122021017591	⤷ Start Trial
Canada	2835595	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 11,278,623

Which drugs does patent 11,278,623 protect, and when does it expire?

Summary for Patent: 11,278,623