Details for Patent: 10,610,523

Which drugs does patent 10,610,523 protect, and when does it expire?

Patent 10,610,523 protects SUBSYS and is included in one NDA.

This patent has nine patent family members in nine countries.

Summary for Patent: 10,610,523

Title:	Sublingual fentanyl spray
Abstract:	The present invention is directed to sublingual formulations containing fentanyl, a pharmaceutically acceptable sale thereof, or derivative thereof, suitable for administration to a patient, and methods for treatment with the formulations.
Inventor(s):	S. George Kottayil, Venkat R. Goskonda, Zhongyuan Zhu, Linet Kattookaran, Neha Parikh
Assignee:	Btcp Pharma LLC
Application Number:	US15/478,499
Patent Claim Types: see list of patent claims	Formulation;

US Patent 10,610,523 Scope, Claim Construction, and US Patent Landscape for a Fentanyl Sublingual Spray (100–800 mcg, 20–60% Ethanol, 4–6% Propylene Glycol; MT to LLOQ ≈ 5 minutes)

Executive summary

US Patent 10,610,523 is a formulation patent focused on a tightly defined fentanyl sublingual spray matrix defined by (i) fentanyl dose range (100–800 micrograms), (ii) ethanol strength (20–60% w/v), (iii) propylene glycol strength (4–6% w/v), and (iv) a performance metric tied to pharmacokinetic onset, expressed as mean time to lower limit of quantification (LLOQ) of fentanyl of about 5 minutes when administered to humans. The claim is “product-by-parameter/performance” and will typically be attacked on (a) lack of novelty over earlier fentanyl sublingual formulations with similar solvents, (b) obviousness around common solvent ranges and dose scaling, and (c) indefiniteness or lack of support for “about 5 minutes” if the patent does not disclose a clear experimental basis and reproducible method. Enforcement leverage is strongest against US entrants that practice the same composition and generate a comparable time-to-quantification profile in the same administration context (sublingual spray).

What patents protect fentanyl sublingual spray formulations with ethanol and propylene glycol?

Core answer: The protection pattern for fentanyl sublingual spray technologies in the US typically clusters into four buckets: (1) composition (solvent system and active concentration), (2) dose unit and delivered dose (microgram range), (3) spray device and delivery method, and (4) PK/BD performance claims (including time to quantification, onset, and Cmax/Tmax windows). US 10,610,523 is primarily in bucket (1) and (2), with bucket (4) added through the LLOQ time parameter.

How US 10,610,523 claim architecture maps to enforceable boundaries

Claim 1 elements (as provided):

1. Sublingual spray formulation
2. Fentanyl: about 100 to about 800 micrograms
3. Ethanol: about 20% to about 60% w/v
4. Propylene glycol: about 4% to about 6% w/v
5. Performance requirement: mean time to LLOQ of fentanyl about 5 minutes when administered to humans
6. Definition: w/v denotes weight by volume

Practical boundary effects:

• Composition boundaries are numeric and fairly narrow for propylene glycol (4–6% w/v).
• The ethanol window (20–60% w/v) is wide, but still constrained.
• The dose window (100–800 mcg) is broad enough to cover multiple intended strengths, but enforcement still requires the specific formulation to fall within the claim.
• The performance metric creates an additional infringement gate that can narrow the set of “within-range compositions” that still meet the claim if time-to-quantification differs due to particle effects, spray plume, excipients, or analytical/LLOQ assay approach.

Neighboring claim themes likely present in the same patent family (and how they affect freedom to operate)

Even though only claim 1 text was provided, formulation patents in this space typically include adjacent dependent claims covering:

• Additional excipients (surfactants, antioxidants, buffering agents)
• Device-related limitations (spray volume per actuation, atomization properties)
• Alternative administration conditions (fasted vs fed)
• Alternative fentanyl salt forms (commonly citrate or free base depending on the program)
• Specific test method definitions for “mean time to LLOQ” (sampling schedule, assay method, quantification limit definition)

Those dependent claims, if present, can extend protection even where a competitor lands partially outside the independent claim.

What is the legal scope of US 10,610,523 claim 1 for infringement?

Core answer: In US practice, claim 1 will be construed as requiring all recited limitations. A competitor must make, use, offer for sale, sell, or import a product that is a sublingual spray formulation meeting the compositional ranges and also meeting the performance metric tied to mean time to LLOQ of fentanyl in humans after administration.

Composition-range infringement logic (typical)

• If a competitor’s ethanol concentration overlaps 20–60% w/v and propylene glycol overlaps 4–6% w/v, those elements are met in a straightforward numerical sense.
• If fentanyl per dose/actuation is within 100–800 mcg, the dose element is met.
• The critical discriminator is “mean time to lower limit of quantification … about 5 minutes.”

Performance-metric infringement risk

Performance or pharmacokinetic parameters can be enforced in at least two ways in US litigation:

• Direct evidence: generated human PK data showing the mean time-to-LLOQ meets the claimed “about 5 minutes” requirement.
• Product-by-process inference: if the formulation is so tied to known physicochemical mechanisms (solubility and permeation kinetics) that meeting the composition ranges predictably yields the claimed metric, plaintiffs can argue equivalence. Defendants typically counter with variability in assay method, LLOQ, sampling times, and administration conditions.

Definitional vulnerability points

The claim ties “LLOQ” to “mean time to lower limit of quantification (LLOQ).” That phrase invites attacks that the claim is not clear without specifying:

• which assay method
• which analytical instrument and validation
• which sampling time grid
• what the numerical LLOQ is
• how “mean time” is computed across subjects and timepoints

If the patent does not contain a clear definition or method for measuring the metric, defendants will argue lack of definiteness and/or failure of written description and enablement for the performance parameter.

When does fentanyl sublingual spray patent protection expire in the US?

Core answer: Patent 10,610,523 is a US utility patent with a presumptive 20-year term from its earliest effective non-provisional filing date, adjusted for patent term adjustment and potential terminal disclaimer. Without the patent’s filing history, expiration calculation cannot be produced precisely from claim text alone.

What can be said from the claim alone

The claim text indicates a formulation and performance metric but does not provide:

• priority date
• non-provisional filing date
• provisional dates
• whether continuations exist
• whether PTA was awarded
• whether there is a terminal disclaimer

Those items control the “when does it lose exclusivity” timeline.

How strong is the patent estate for this fentanyl sublingual spray?

Core answer: US 10,610,523’s strength depends on whether the patent provides:

1. Broad, well-supported compositional disclosure for the specified ethanol and propylene glycol windows.
2. Reproducible human PK data linking the formulation to a ~5 minute time-to-LLOQ.
3. Tight dependency between solvent system and early quantification (the performance element).

Strength indicators

• Numeric windows for ethanol and propylene glycol provide a clear scope that can be enforced against close variants.
• The performance metric can deter “design-around” by changing excipients if that change alters time-to-quantification beyond the “about 5 minutes” tolerance.

Strength detractors

• If prior art exists with similar solvent ranges and fentanyl dosing using comparable sublingual delivery, obviousness risk rises.
• If the “about 5 minutes” is not anchored to a defined analytical and dosing protocol, defendants can argue that infringement cannot be determined reliably.

What formulations are protected by US 10,610,523 and how do design-arounds work?

Core answer: Protection is limited to sublingual spray formulations that meet all three numeric composition constraints and the PK metric.

High-probability design-around levers

1. Shift propylene glycol outside 4–6% w/v (for example, 3.5% or 6.5%).
2. Shift ethanol outside 20–60% w/v.
3. Shift fentanyl dosing per actuation outside 100–800 mcg.
4. Keep composition within range but alter early absorption kinetics such that mean time-to-LLOQ is no longer “about 5 minutes.”

Practical feasibility of each lever

• Solvent substitution is often feasible for formulation teams.
• Hitting a performance target while moving solvents is non-trivial, but it is also a typical development objective for competitors.
• The biggest litigation risk for a design-around is if a competitor still lands within ranges but claims performance is different due to assay methodology; courts often focus on actual product behavior rather than plaintiffs’ expectations.

Which companies are likely to face risk from US 10,610,523?

Core answer: Risk clusters around companies developing generic or follow-on fentanyl products in the US under:

• ANDA or 505(b)(2) pathways for small-molecule fentanyl formulations, and
• any US development of fentanyl sublingual sprays.

However, company names cannot be identified from the claim text alone without the patent’s assignee, related family members, and the Orange Book entry for the relevant fentanyl product.

What patent litigation affects fentanyl sublingual sprays with PK onset claims?

Core answer: Litigation risk attaches when a downstream filing (ANDA/505(b)(2)) is positioned to enter while the formulation and method-of-use patents are active, and when the entrant’s product has overlapping solvent and dose ranges.

A proper map requires:

• the asserted patent list in specific litigations
• the court docket
• whether 10,610,523 has been asserted in specific Paragraph IV events
• settlement agreement terms (carve-outs, at-risk launches, stipulated injunction dates)

No such docket-specific data can be derived from the claim text alone.

What is the Orange Book status of the fentanyl product covered by US 10,610,523?

Core answer: Orange Book status requires identifying the listed drug product (RLD), then checking listed patents and their expiration dates.

The provided information does not include the RLD name, dosage form, label strength(s), or patent listing identifiers, so the Orange Book status cannot be produced accurately.

How does US 10,610,523 compare with other fentanyl sublingual formulation patents?

Core answer: The distinguishing feature of US 10,610,523 is that it includes a human PK performance constraint in the independent claim, using mean time to LLOQ as a proxy for onset.

Common competitor claim patterns (typical)

• Composition-only claims: solvent system and concentration ranges without PK metrics.
• Device-only claims: spray actuation volume, nozzle geometry, atomization parameters.
• Method-of-use claims: instructions or dosing regimens.
• Alternative performance metrics: Tmax, Cmax at early timepoints, AUC(0-t), or time to first detectable concentration.

A claim that includes time-to-LLOQ is often harder to avoid than a composition-only claim because it ties formulation to measurable in vivo behavior.

What generic entry risks exist for fentanyl sublingual sprays in the US?

Core answer: Generic/follow-on risk depends on whether the generic applicant can:

• match the solvent and dose ranges exactly, and
• replicate the human time-to-LLOQ metric.

Entrants can typically avoid a composition claim by changing solvent concentrations or formulation composition. Avoiding a performance-metric requirement is harder if the competitor uses the same administration mode and still produces equivalent early absorption.

Key risk scenario

• If an entrant’s product stays within the ethanol and propylene glycol windows and delivers fentanyl in the claimed microgram range, then the performance requirement becomes the primary litigation battleground.

Patent landscape essentials: what to extract beyond claim text (but not infer here)

A complete landscape for US 10,610,523 requires the following objects, none of which are provided in the prompt:

• patent assignee and inventors
• application number, priority/filing dates
• specification disclosure of the LLOQ measurement method
• the full claim set and dependent limitations
• related family members and continuations
• prosecution history (especially claim amendments tied to the performance metric)
• any listed Orange Book patents for the corresponding FDA-approved product
• whether 10,610,523 has been asserted in specific court cases

Because those inputs are not included, a detailed, accurate landscape with dates, competitors, and litigations cannot be compiled.

Key Takeaways

• US 10,610,523 claim 1 is a sublingual fentanyl spray formulation claim defined by specific numeric composition ranges for ethanol (20–60% w/v), propylene glycol (4–6% w/v), and fentanyl dose (100–800 mcg), plus a human PK onset constraint: mean time to LLOQ of about 5 minutes.
• The performance metric narrows infringement to products that not only match composition and dose but also produce comparable early human quantification.
• The strongest legal vulnerabilities for defendants are (i) freedom-to-design-around via solvent and dose shifts, and (ii) attacking indefiniteness/support if the patent does not clearly define how the “about 5 minutes” time-to-LLOQ is measured.
• A full US landscape (expiration timeline, Orange Book status, litigation impact, and competitor mapping) cannot be completed from claim text alone.

FAQs

1. What does “about 5 minutes mean time to LLOQ” practically require for infringement? It requires human data showing the product’s mean time until fentanyl becomes quantifiable under the assay/LLOQ framework used to generate “LLOQ time” consistent with the patent’s measurement approach.
2. Can a generic avoid infringement by lowering propylene glycol below 4% w/v? A solvent-range change outside 4–6% w/v is a direct design-around if all other claim elements remain unmet.
3. Does matching ethanol but changing propylene glycol necessarily avoid the claim? Yes, because claim 1 requires all recited compositional limits simultaneously along with the performance metric.
4. If an entrant matches composition, can it still avoid the claim by using a different analytical method that changes LLOQ time? Entrants will argue measurement differences; plaintiffs will focus on product behavior and the claim’s definition of LLOQ timing as supported by the patent’s disclosed method.
5. Are spray-device parameters part of claim 1 as provided? Claim 1 includes “sublingual spray formulation” but the provided text does not add device-specific actuation/nozzle limitations; any device limitations would require dependent claims or other claim language not included here.

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References (APA)

1. United States Patent 10,610,523.

Drugs Protected by US Patent 10,610,523

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Btcp Pharma	SUBSYS	fentanyl	SPRAY;SUBLINGUAL	202788-001	Jan 4, 2012		DISCN	Yes	No			Y
Btcp Pharma	SUBSYS	fentanyl	SPRAY;SUBLINGUAL	202788-002	Jan 4, 2012		DISCN	Yes	No			Y
Btcp Pharma	SUBSYS	fentanyl	SPRAY;SUBLINGUAL	202788-003	Jan 4, 2012		DISCN	Yes	No			Y
Btcp Pharma	SUBSYS	fentanyl	SPRAY;SUBLINGUAL	202788-004	Jan 4, 2012		DISCN	Yes	No			Y

International Family Members for US Patent 10,610,523

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2008282743
Canada	2698749
Denmark	2180844
European Patent Office	2180844