Scope and Claims Analysis for US Patent 11,541,043: Dihydroergotamine 1 mg/mL, pH 3–5, and Prefilled Single-Use Delivery Device (Not User Adjustable)

US 11,541,043 is drafted to cover a narrow, tightly defined product bundle: (i) a parenteral dihydroergotamine (DHE) liquid formulation at about 1 mg/mL with a controlled acidic pH range, and (ii) containment of that formulation in a preassembled, prefilled, single-use delivery device that delivers a fixed dose (0.5 to 3 mg) without user adjustment of dose or dosing rate. The claims also add overlapping dependent claim layers covering buffer/pH maintenance, specific DHE salt (mesylate), dose anchoring to about 1 mg, and specific autoinjector mechanical architectures (tension/injection springs, predetermined preload/compression, trigger-pawl-plunger safety mechanisms, needle guard, and a suction cup for cap removal).

Below is a claim-by-claim scope map, followed by a structured patent-landscape view of what this patent is likely to block, how it can be designed around, and which adjacent US filings typically compete for the same claim space.

What does US 11,541,043 claim cover: DHE acidic parenteral formulation in a fixed-dose prefilled device?

Short answer: The independent claim (claim 1) is a product claim on a parenteral composition plus its delivery device context. It requires all of: DHE (or salt) at about 1 mg/mL, one or more pH maintaining/adjusting agents producing pH 3 to 5, and a prefilled single-use delivery device that can deliver 0.5 to 3 mg DHE without user adjustability of dose and dosing rate.

Claim 1 scope elements (all required)

Claim 1 can be segmented into five mandatory limitations:

Dosage form type
- “parenteral pharmaceutical composition” (implies injectable, not oral/topical).
Active and concentration
- “dihydroergotamine or pharmaceutically acceptable salt”
- “concentration of about 1 mg/mL”
Acidic pH + formulation excipients
- contains one or more “pH maintaining or pH adjusting agents”
- resulting “pH … between about 3 to about 5”
Device context
- “contained in a preassembled, prefilled, single-use delivery device”
- “capable of delivering a dose … between about 0.5 to about 3 mg”
- “not user adjustable with respect to dosage or dosing rate”
Dose delivery constraints
- Fixed-dose and fixed dosing rate are inferred from “not user adjustable” and “device capable of delivering a dose … between 0.5 to 3 mg.”

Why the device language matters

The claim is not limited to a formulation in a generic vial/syringe. It conditions patent coverage on the formulation being “contained in” a particular delivery device class, and it restricts covered embodiments by tying the device to fixed-dose, non-user-adjustable delivery. That is often a key litigation lever in combination product patents: defendants can try to change device architecture, adjustability logic, or packaging configuration to avoid the “not user adjustable” requirement.

What formulations are protected by US 11,541,043: pH 3–5, buffers, and controlled ranges like 3.4–4.9?

Short answer: The independent claim protects acidic pH 3–5 DHE compositions at about 1 mg/mL that use pH maintaining/adjusting agents. Dependent claims tighten to buffer-based systems and specific pH windows (3.4–4.9), adding evidentiary hooks for composition-specific infringement.

Dependent claim layers for formulation

Claim 2: pH agents include a buffer
Claim 3: pH maintained between 3.4 and 4.9
Claim 4: pH maintained between 3.4 and 4.9 (independent duplicate tightening language)

Practical scope implications

If a competitor’s DHE injectable hits pH 3.0–3.39 or >5.0, it may avoid claims 1/3/4 depending on “about” interpretation.
If pH is controlled via non-buffer systems (e.g., acid/base salt balance without classic buffer pairing), claim 2 may be vulnerable, while claim 1 can still read if “pH maintaining or pH adjusting agents” still apply.
If the formulation is at materially different concentration than “about 1 mg/mL,” both claim 1 and any salt/dose dependents become vulnerable.

Which dihydroergotamine salts and doses are covered: mesylate at about 1 mg and 0.5–3 mg device deliverable?

Short answer: Claim 5 narrows to DHE mesylate. Claim 6 ties dose to about 1 mg. The independent claim already supports a device delivering 0.5 to 3 mg.

Key dependent claim anchors

Claim 5: DHE is dihydroergotamine mesylate
Claim 6: dose is about 1 mg of dihydroergotamine mesylate

Claim construction pressure points

“about 1 mg/mL” and “about 1 mg” are likely to trigger tolerance arguments (manufacturing target vs measured spec).
If a commercial product is formulated as DHE mesylate at a different mg/mL or delivers a fixed dose outside the 0.5–3 mg range, it may avoid some dependent claims and potentially claim 1 entirely.

How do the autoinjector mechanical claims expand infringement risk: tension spring, injection spring compression, trigger-pawl-plunger, and needle safety?

Short answer: Claims 7–20 add device-mechanism limitations that can broaden or narrow infringement depending on the defendant’s autoinjector design. If the accused device uses the claimed spring/trigger architecture, those dependent claims become strong infringement candidates; if it uses alternative architectures, the patent may still reach claim 1 if the accused device is a “prefilled single-use delivery device” that is not user adjustable.

Mechanical dosing rate via spring architecture

Claim 7: autoinjector includes a tension spring; dosing rate depends on degree of tension
Claim 8: predetermined tension provides desired dosing rate
Claim 9: predetermined tension is preloaded

OR, alternatively:

Claim 10: autoinjector includes injection spring; dosing rate depends on degree of compression
Claim 11: compression degree is predetermined and not user adjustable

Infringement strategy impact

These are classic “mechanism-specific” dependent claims. If a competitor uses an electromechanical pump, solenoid timing, constant-spring calibration without “tension depends dosing rate” linkage, or software-controlled injection velocity independent of spring preload/compression, they can potentially avoid these dependents while remaining within the broader packaging and pH constraints of claim 1.

Actuation and retention architecture

Claim 13: trigger for actuating an actuating lever maintained under pressure in an armed position
Claim 14: composition contained by a plunger
Claim 15: plunger contained until activated by a trigger
Claim 16: pawl releasably interfaces with a retainer in armed position until trigger releases pawl
Claim 17: trigger activates a piston rod depressing the plunger and delivering dose through an injection needle

Needle safety and cap removal

Claim 18: moveable safety shield movable around needle to protect against inadvertent contact
Claim 20: suction cup facilitates removal of safety cap

Armed-state kinetic linkage

Claim 19: piston rod retained keeping tension spring under compression; piston rod contacts plunger; trigger releases piston rod so tension spring urges it forward

Scope relationship

Claims 14–17 and 19 are internally coherent: the device’s armed state retains energy in springs and releases it through a trigger-linked path to drive a plunger/piston rod and needle delivery.
Claims 18 and 20 target safety and usability features that are common in auto-injector families and can be used as infringement differentiators in litigation discovery.

What is the likely patent landscape around US 11,541,043: formulation + fixed-dose device packaging + autoinjector mechanisms

Because only the claim set text is provided and no prosecution history, assignee, or bibliographic data is included here, the landscape is framed at the claim-space level rather than by enumerating specific co-owned US applications or foreign family members.

Adjacent claim clusters that typically overlap this kind of patent

DHE parenteral liquid formulation patents
- acidic pH stabilization
- buffers and anti-oxidants (where applicable)
- stability against degradation products and precipitation control
- specific concentration targets (around 1 mg/mL is uncommon enough to create a differentiating spec)
Prefilled autoinjector and single-use device patents
- fixed-dose cartridges
- non-user-adjustable dosing rate control
- spring preload/compression-based metering
- armed/trigger-release retention mechanisms (pawl/retainer)
- needle shielding safety mechanisms
Combination product patents (drug-in-device)
- device containment language (“contained in … device”)
- deliverable dose range tied to fill volume and concentration
- non-adjustability constraints that reduce design-around options for off-the-shelf injectors

How competitors usually respond to this combination claim style

Use the same drug and similar pH but change device so dose or dosing rate is user adjustable, or is controlled by a different mechanism not dependent on spring tension/compression in the claimed way.
Use a different formulation concentration or pH window outside “between about 3 and about 5” or “3.4 to 4.9.”
Package in a different device class (e.g., vial with syringe) to avoid “prefilled single-use delivery device” wording, while keeping parenteral administration.
Use a device architecture without pawl/retainer release path, without plunger-contained delivery, or without the specific needle safety shield geometry claimed.

Where infringement risk is highest: combinations that satisfy claim 1 while also matching dependents 2–4 and 7–20

Short answer: The largest infringement footprint occurs when a commercial DHE auto-injector uses:

DHE mesylate at about 1 mg/mL,
acidic pH maintained in the 3.4–4.9 band using buffer agents,
a prefilled, fixed-dose single-use injector with non-adjustable dosing rate, and
spring/trigger retention mechanisms plus needle shield and safety cap features that closely match claims 7–20.

High-risk product profiles

Claim bundle	If accused product matches	Litigation leverage
Claim 1 + 2–4	Acidic buffered DHE at pH 3–5 and especially 3.4–4.9, about 1 mg/mL	Strong formulation infringement in addition to device containment
Claim 1 + 5–6	DHE mesylate with ~1 mg dose	Narrows design-around to alternative salts and/or dose targets
Claim 1 + 7–9	Spring tension preload controls dosing rate	Mechanical dependence creates clear testing/discovery targets
Claim 1 + 10–11	Compression degree controls dosing rate; not user adjustable	Helps quantify “dosing rate” control linkage
Claim 1 + 13–17	Specific armed trigger-pawl/plunger piston/needle delivery chain	Often robust for mechanical infringement analysis
Claim 1 + 18	Needle safety shield movable about needle	Feature-based proof; correlates with product teardown
Claim 1 + 20	Suction cup for safety cap removal	Niche but can be highly identifying

Which design-around paths are most credible based on the claim language

Short answer: The claim’s structure gives multiple levers: pH window, concentration, DHE salt, dose range, and device non-adjustability and mechanism of dosing rate control.

A. Formulation design-around

Shift pH outside 3–5 (or outside the tighter 3.4–4.9 band)
Reduce or increase concentration away from “about 1 mg/mL”
Use a different salt form (avoid “dihydroergotamine mesylate” for claims 5–6)
Use pH agents not meeting “buffer” (to avoid claim 2) if still meeting claim 1 pH range

B. Device design-around

Change from a prefilled single-use device into another packaging format not meeting claim 1 containment framing
Ensure dosing rate is user adjustable (to directly contradict “not user adjustable with respect to… dosing rate”)
Engineer dosing rate control independent of spring tension/compression degrees and not “predetermined amount of tension/preload” in the claimed manner
Replace pawl/retainer release and plunger/piston rod triggering chain with an alternative retention/release method
Replace needle safety shield architecture so it is not “moveable about an injection needle” as claimed
Remove suction cup safety cap removal feature if relying on claim 20

What this patent likely blocks commercially: fixed-dose DHE self-injection with controlled acidic formulation

Short answer: US 11,541,043 targets a commercial product class that is part formulation (acidic stabilized DHE) and part delivery device (prefilled single-use injector with fixed dose and fixed dosing rate, often spring-driven). It creates licensing pressure on any developer or marketer using that combined design space.

Revenue exposure mechanics

Claim 1’s range (DHE 0.5–3 mg deliverable; about 1 mg/mL fill concentration; pH 3–5) is broad enough to cover typical fixed-dose injector products if their specs land in those ranges.
Dependent claims 3–4 (pH 3.4–4.9) and 5–6 (mesylate; about 1 mg) give additional stacking protection around common optimization targets.

When does exclusivity end for US 11,541,043 and how does it affect generic or alternative-device entry?

Short answer: This patent’s enforceability window depends on its filing date and any patent-term adjustment and is not determinable from the claim text alone. Without bibliographic data (filing date, priority date, PTA, and maintenance status), a precise “expiration date” or exclusivity timeline cannot be provided.

What Paragraph IV or biosimilar-style challenges apply to this patent

Short answer: This is a small-molecule parenteral formulation and device combination. It is not a biologic, so “biosimilar” frameworks do not map to the claim set. Generic entry would be governed by the usual Hatch-Waxman Paragraph IV pathway only to the extent an ANDA references the relevant NDA and the Orange Book lists this patent for the referenced product. Patent eligibility on the Orange Book and any litigation posture cannot be determined from the claim text alone.

Key takeaways

Claim 1 is a combination product claim: DHE (or salt) at about 1 mg/mL, acidic pH 3–5, and containment in a preassembled prefilled single-use delivery device delivering 0.5–3 mg without user adjustment of dose or dosing rate.
Dependent claims add narrowing anchors: buffered systems, pH 3.4–4.9, DHE mesylate, and about 1 mg dose.
Device mechanics are a second infringement axis: multiple dependent claims target spring-based dosing rate control and specific armed/trigger/pawl/plunger needle delivery and safety features.
Design-around is feasible but must be coordinated: altering pH/concentration/dose range and changing device adjustability and metering mechanism are the primary levers.
Highest litigation risk sits with products that match both the acid-stabilized DHE fill specs and the spring/trigger auto-injector architecture.

FAQs

1) Can a competitor avoid US 11,541,043 by changing DHE concentration slightly?
If the accused formulation no longer meets “about 1 mg/mL” and the measured concentration falls outside reasonable tolerance, claim 1 and any dose-linked dependents are exposed.

2) Does the patent require a buffer specifically?
No. Claim 1 covers “pH maintaining or pH adjusting agents.” Claim 2 adds the buffer limitation.

3) If a product uses spring preload to meter dosing rate, does it automatically infringe?
Not automatically. It must also meet the formulation and containment limitations of claim 1, and match the specific dependency chain (tension vs injection compression, predetermined preload/compression, and non-user adjustability).

4) Would switching from an autoinjector to a vial and syringe eliminate infringement of claim 1?
It can, if the drug is not “contained in a preassembled, prefilled, single-use delivery device” as required by claim 1.

5) Are needle safety and suction cup features required for infringement?
No. Those are in dependent claims 18 and 20. The baseline infringement risk begins with claim 1, and the safety/cap features matter only for the dependents.

References

United States Patent US 11,541,043, claims 1–20 (provided claim text).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Amneal	BREKIYA (AUTOINJECTOR)	dihydroergotamine mesylate	SOLUTION;SUBCUTANEOUS	215400-001	May 14, 2025		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

Details for Patent: 11,541,043

Which drugs does patent 11,541,043 protect, and when does it expire?

Summary for Patent: 11,541,043