US Patent 11,865,112 (Nalmefene + Magnesium Chloride): Claims Scope and U.S. Landscape
United States Patent 11,865,112 claims a nalmefene parenteral formulation that uses magnesium chloride (MgCl2) as a parenteral adjuvant at 0.5% to 1.0% (w/v) to drive faster opioid antagonistic action and accelerated nalmefene exposure after intramuscular (IM) or subcutaneous (SC) dosing, plus related rescue and pre-entry prophylaxis methods and an injection-device drug delivery system.
What is the core claimed invention?
Primary claim structure (independent claim set)
Claim 1 is the core formulation claim:
- Drug: nalmefene or pharmaceutically acceptable salt
- Dose form: parenteral
- Adjuvant: magnesium chloride at 0.5% (w/v) to 1% (w/v)
- Performance requirement: provides time to onset of opioid antagonistic action of less than 5 minutes after IM or SC injection to a subject experiencing opioid agonist overdose
Claim 11 is a core method claim for overdose rescue that incorporates the same formulation and the <5-minute onset requirement.
Claim 12 is a prophylactic/“preparation prior to entry into a locale” method that incorporates:
- nalmefene + MgCl2 (0.5% to 1%)
- mean time to maximum plasma concentration (Tmax) of nalmefene about 2.0 hours or less after IM dosing in healthy subjects.
Claims 13-14 cover a drug delivery system (injection device containing the claimed formulation), with example container/device types.
Key dependent refinements (what narrows scope)
- Claims 2-3, 5-6 narrow IM Tmax to progressively shorter windows:
- Claim 2: Tmax about 2.0 hours or less
- Claim 3: Tmax about 1.0 hour or less
- Claim 5: Tmax about 1.5 hours or less
- Claim 6: Tmax about 0.5 hour or less
- Claims 4, 7-8 narrow clinical onset time:
- Claim 4: clinically manifested onset about 4 minutes or less (IM or SC)
- Claim 7: clinically manifested onset <5 minutes after IM
- Claim 8: clinically manifested onset <5 minutes after SC
- Claim 9 requires comparative absorption enhancement: adjuvant promotes systemic absorption rate and/or total amount absorbed compared to same formulation without MgCl2.
- Claim 10 fixes drug to nalmefene hydrochloride.
- Claims 15-17 lock MgCl2 at a single point:
- MgCl2 about 0.9% (w/v) in formulation (claim 15)
- same in overdose rescue method (claim 16)
- same in pre-entry method (claim 17)
What exactly do the claims cover? (Element-by-element scope)
A. Formulation scope (Claim 1 and dependent claims)
Claim 1 defines the formulation by:
- Active: nalmefene or a pharmaceutically acceptable salt
- Parenteral vehicle/adjuvant system: includes MgCl2 at 0.5% to 1% (w/v) as a parenterally acceptable adjuvant
- Pharmacokinetic/pharmacodynamic performance:
- Time to onset of opioid antagonistic action < 5 minutes
- for IM or SC injection
- to a subject experiencing an opioid agonist overdose
Claims 2-3 and 5-6 then further constrain the formulation based on IM Tmax in healthy subjects:
- Tmax windows become progressively tighter:
- ≤2.0 hours (Claim 2)
- ≤1.0 hour (Claim 3)
- ≤1.5 hours (Claim 5)
- ≤0.5 hour (Claim 6)
Claims 4, 7, 8 constrain performance for clinically manifested onset:
- ≤4 minutes (Claim 4, IM or SC)
- <5 minutes after IM (Claim 7)
- <5 minutes after SC (Claim 8)
Claim 9 adds a comparative requirement:
- The MgCl2 adjuvant must promote absorption rate and/or total absorbed amount vs a matched formulation lacking MgCl2.
Claim 10 narrows active to:
Claim 15 narrows the adjuvant concentration:
- MgCl2 at about 0.9% (w/v)
B. Use scope
Overdose rescue method (Claim 11)
- Intramuscularly or subcutaneously administer the claimed formulation to a subject in need thereof, with the same:
- MgCl2 0.5%-1.0% (w/v)
- nalmefene or salt
- <5 minutes time to onset of opioid antagonistic action
Pre-entry prophylaxis method (Claim 12)
- Administer prior to entering a locale with potentially toxic opioid levels so the subject is protected from an opioid overdose resulting from entry
- Incorporates:
- MgCl2 0.5%-1.0% (w/v)
- nalmefene or salt
- IM Tmax ≤2.0 hours in healthy subjects
Claim 17 fixes MgCl2 to about 0.9% in this method.
C. Drug delivery system scope (Claims 13-14)
- A drug delivery system with an injection device containing the formulation of Claim 2 (not Claim 1)
- Containers/device examples:
- pre-filled syringe
- vial
- injection pen
- auto-injector
This structure indicates device claims are tethered to the formulation defined by Claim 2 (Tmax ≤2.0 hours post-IM in healthy subjects), not to the broader <5-minute onset definition of Claim 1.
What are the measurable claim boundaries (where design-arounds and infringement hinge)?
1) Magnesium chloride concentration window
- Primary: 0.5% to 1% (w/v) (Claims 1, 11, 12)
- Narrow: about 0.9% (w/v) (Claims 15-17)
Practical boundary: any candidate formulation falls outside the literal adjuvant concentration range if MgCl2 is below 0.5% or above 1% (w/v). At 0.9%, it falls squarely within a dedicated dependent claim.
2) Route of administration
- Both IM and SC are covered (Claim 1; Claims 7-8)
- Device claims are compatible with IM/SC dosing because the underlying formulation claim 2 is still a parenteral IM performance constraint.
3) Performance requirements
The patent is performance-structured. Key measurable endpoints:
A. Opioid antagonistic action onset
- Claim 1: <5 minutes
- Claim 4: about 4 minutes or less
- Claims 7-8: <5 minutes by route, clinically manifested
B. Nalmefene exposure: IM Tmax
- Claim 2: about 2.0 hours or less
- Claim 3: about 1.0 hour or less
- Claim 5: about 1.5 hours or less
- Claim 6: about 0.5 hour or less
- Claim 12 links prophylaxis to Tmax ≤2.0 hours in healthy subjects
4) Comparative requirement
- Claim 9 requires that MgCl2 increases systemic absorption rate and/or total amount absorbed versus a formulation without MgCl2.
This matters because some evaluators may try to reframe development as “different formulation” rather than “same formulation without MgCl2.” The claim uses an internal control concept: the same formulation but without the adjuvant.
How broad is the claim scope in the real world?
Broadest formulation trigger
Claim 1 is broadest because it ties:
- nalmefene + MgCl2 within a defined concentration range
- to a pharmacodynamic endpoint (<5 minutes antagonistic action onset)
- in IM or SC overdose context
That breadth does not require a specific Tmax number in Claim 1, unlike Claim 2 and onward.
Narrowest performance triggers
Claims 3 and 6 narrow Tmax aggressively:
- ≤1.0 hour (Claim 3)
- ≤0.5 hour (Claim 6)
If the development target misses those thresholds, it may still fall under Claim 1 (if <5-minute antagonistic onset is achieved), or under Claim 2 (if Tmax ≤2 hours) depending on measured outcomes.
Device claim tethering
Device claims (Claims 13-14) are limited to “drug delivery system containing a parenteral formulation of claim 2,” meaning:
- the formulation in the device must satisfy the Tmax ≤2 hours constraint.
A product that meets <5-minute onset (Claim 1) but does not meet the Claim 2 Tmax threshold can potentially avoid the device claims while remaining within the formulation/method claims, depending on how the product is launched and what performance data is shown.
What is the U.S. patent landscape implied by this claim set?
Landscape structure typically created by this type of claim
This patent’s claim architecture signals a landscape with three layers of enforceability and commercial relevance:
-
Composition-of-matter-adjacent formulation layer
- Covers a specific adjuvant (MgCl2) in a narrow concentration window (0.5%-1%)
- plus performance endpoints
-
Method-of-use layer
- Overdose rescue (treatment)
- Pre-entry prophylaxis (prevention)
-
Product engineering and commercial packaging layer
- Injection-device embodiments that contain the specific formulation performance of Claim 2
Where conflicts are most likely
Given the measured endpoints, infringement risk concentrates around products that:
- deploy nalmefene for opioid overdose using IM/SC
- use MgCl2 as a formulation adjuvant in 0.5%-1%
- generate dosing-time outcomes that support:
- <5-minute antagonistic action onset
- and/or IM Tmax ≤2 hours (device claim relevance)
Where design-arounds are most likely
Potential freedom-to-operate strategies typically hinge on two dials only:
- MgCl2 concentration: move outside 0.5%-1% or avoid the “about 0.9%” point
- Performance endpoints: avoid demonstrating endpoints that land inside the claim-defined thresholds (especially Tmax windows used to tether device claims)
This claim set is not limited to a particular container or device, and it is not limited to a fixed nalmefene dose in the excerpted claims. So the main “engineering lever” is adjuvant concentration paired with endpoint outcomes.
Who benefits from the layered dependent claims (and why it matters to competitors)?
Dependence pattern that increases litigation coverage
The patent uses performance-dependent dependent claims to create multiple overlapping coverage points:
- one path through pharmacodynamic onset (<5 minutes; ≤4 minutes)
- a second path through pharmacokinetic Tmax (≤2h; ≤1h; ≤1.5h; ≤0.5h)
- a third path through comparative absorption enhancement (with vs without MgCl2)
- plus a third “productization” path via device claims tied to Claim 2
This reduces the chance that a competitor can avoid all claims by missing a single target metric.
Claim-by-claim scope map (what each claim adds)
| Claim |
What it adds beyond the core concept |
Narrowing / measurable boundary |
| 1 |
Core formulation + MgCl2 |
MgCl2 0.5%-1%; time to onset of opioid antagonistic action <5 min after IM/SC overdose |
| 2 |
IM exposure constraint |
Mean IM Tmax ≤2.0 h |
| 3 |
Tighter IM exposure |
Mean IM Tmax ≤1.0 h |
| 4 |
Clinical onset tightens |
Clinically manifested onset ≤4 min (IM or SC) |
| 5 |
Alternative intermediate Tmax |
Mean IM Tmax ≤1.5 h |
| 6 |
Tightest IM exposure |
Mean IM Tmax ≤0.5 h |
| 7 |
Route-specific clinical onset |
Clinically manifested onset <5 min after IM overdose |
| 8 |
Route-specific clinical onset |
Clinically manifested onset <5 min after SC overdose |
| 9 |
Comparative adjuvant effect |
MgCl2 increases systemic absorption rate and/or total absorbed vs without MgCl2 |
| 10 |
Active specificity |
nalmefene hydrochloride |
| 11 |
Method for overdose rescue |
IM/SC administration of Claim 1 formulation; onset <5 min |
| 12 |
Pre-entry prophylaxis |
Prior to entry; IM healthy-subject Tmax ≤2.0 h |
| 13 |
Device claim tied to Claim 2 |
Injection device containing Claim 2 formulation |
| 14 |
Exemplary device types |
pre-filled syringe, vial, injection pen, auto-injector |
| 15 |
Fixed adjuvant concentration |
MgCl2 about 0.9% (w/v) |
| 16 |
Method MgCl2 fix |
MgCl2 about 0.9% for rescue method |
| 17 |
Prophylaxis MgCl2 fix |
MgCl2 about 0.9% for pre-entry method |
Key Takeaways
- Claim 1 is the anchor: nalmefene (or salt) + MgCl2 0.5%-1% (w/v) in a parenteral formulation that delivers <5-minute opioid antagonistic onset after IM or SC dosing for opioid overdose.
- The patent also locks in multiple IM Tmax thresholds (≤2.0 h, ≤1.5 h, ≤1.0 h, ≤0.5 h) that can expand coverage depending on what data a product generates.
- Device claims (13-14) are constrained to Claim 2 formulation through an IM Tmax ≤2.0-hour requirement, not to the broader <5-minute onset definition.
- MgCl2 at about 0.9% (w/v) is a dedicated sub-scope across formulation and both method claims.
- Comparative absorption (Claim 9) adds a second infringement hook: MgCl2 must improve absorption versus the same formulation without MgCl2.
FAQs
1) Does the patent cover both intramuscular and subcutaneous dosing?
Yes. Claim 1 requires <5-minute antagonistic onset after IM or SC injection, and Claims 7-8 define route-specific clinically manifested onset.
2) Is magnesium chloride optional or required?
It is required. MgCl2 at 0.5%-1% (w/v) is an explicit element of Claim 1 and the related method claims.
3) What performance metrics matter most for infringement risk?
The measurable endpoints are: time to onset of opioid antagonistic action (<5 minutes; ≤4 minutes clinically manifested) and IM mean Tmax (≤2.0 h, with dependent claims down to ≤0.5 h).
4) Do the injection-device claims cover every formulation in the patent?
No. Claims 13-14 require an injection device containing a formulation of Claim 2 (IM mean Tmax ≤2.0 hours).
5) Is the patent limited to nalmefene hydrochloride?
No. Claim 1 covers nalmefene or salts; Claim 10 narrows to nalmefene hydrochloride.
References
[1] United States Patent 11,865,112. Claimed subject matter as provided in the user prompt (Claims 1-17).
