Executive summary US Patent 12,121,582 claims an injectable, citrate-buffered formulation of a “compound of formula (I)” at pH 4–6 (preferably 4–5.5, ~5) with citrate buffer 10–20 mM (preferably ~10 mM) and dose concentration 0.2–3 mg/mL (preferably ~0.3–1.2 mg/mL; narrower 0.3–0.6 mg/mL), plus method-of-treatment claims for microbe-mediated diseases via IV administration. The claim set is primarily formulation-positioned (buffer system, pH, ionic strength, concentration windows, vehicle) with some salt-form hooks (acetate, L-lactate). The litigation and Orange Book/approval linkage cannot be analyzed without the identity of formula (I) and the patent’s publication history, assignee, and family members.

US Patent 12,121,582 scope: what does the claim language cover for injectable citrate-buffered pH 4 to 6 formulations?

What is claimed at the highest level?

Independent claim 1 defines a narrow formulation architecture:

Dosage form: injectable pharmaceutical formulation
Active: “a compound of formula (I) or a pharmaceutically acceptable salt thereof”
Buffering: formulation is buffered to pH 4–6
Buffer identity: citrate buffer

Claim 1 is a structural/functional formulation claim: it does not claim a synthesis step; it claims a final injectable composition meeting buffer identity and pH range.

Implication for enforcement
A generic or competitor formulation must match (i) compound-of-Formula-(I), (ii) citrate buffer, and (iii) buffered pH 4–6. Differences in excipients are addressed by dependent claims, but the independent claim can still read on other vehicles so long as the citrate-buffer/pH parameters are met.

What dependent claims narrow the formulation space?

Dependent claims tighten claim 1 using parameter windows and composition features:

Buffer strength and pH windows (claims 3, 4, 10, 11, 12, 13, 14, 16)

Claim 3: citrate buffer 10–20 mM; pH 4–5.5; compound concentration 0.2–3 mg/mL (free base basis); plus a pharmaceutically acceptable vehicle.
Claim 4: citrate buffer 10 mM; compound concentration 0.3–1.2 mg/mL.
Claim 5: further narrows compound concentration 0.3–0.6 mg/mL (presumably still within the claim 4 conditions).
Claim 10: pH 4–5.5.
Claims 11 and 12: pH 4–5 and about 5.
Claim 13: citrate buffer 10–20 mM.
Claim 14: citrate buffer 10 mM.
Claim 16: pH 5 (within the narrowed contexts of claims 3–5).

Enforcement consequence
If a competitor uses citrate buffer at pH 5 but outside concentration windows, it may still infringe claim 1 (if concentration is not part of claim 1) but will be harder to ensnare on the narrower claims. If the competitor uses non-citrate buffering (phosphate/acetate) but matches pH, claim 1 likely avoids infringement because buffer identity is a limiting element.

Vehicle/solvent system (claims 2 and 15)

Claim 2: includes a pharmaceutically acceptable vehicle.
Claim 15: vehicle selected from normal saline, 5% dextrose, or mixtures.

This creates two tiers:

Claim 1 allows any pharmaceutically acceptable vehicle.
Claim 15 restricts to conventional infusion vehicles. If the accused formulation uses a different vehicle system, claim 15 does not apply, but claim 1 or claim 2 may still.

Salt form hooks (claims 6 and 17)

Claim 6: compound employed as a pharmaceutically acceptable salt (no restriction on which in claim 6).
Claim 17: salt selected from acetate and L-lactate.

This matters for design-around:

If a competitor uses a different pharmaceutically acceptable salt (e.g., HCl, maleate, sulfate, citrate salt), claim 17 may not read, but claim 6 and claim 1 could still read because claim 1 includes “a compound of formula (I) or a pharmaceutically acceptable salt thereof.”

Product-by-parameter summary table

Claim	Key limiting elements	Practical formulation “fingerprint”
1	Injectable; compound of formula (I) or salt; citrate buffer; pH 4–6	Citrate-buffered IV at mildly acidic pH
2	Claim 1 + “pharmaceutically acceptable vehicle”	Generic vehicle language
3	Claim 1 + citrate 10–20 mM; pH 4–5.5; concentration 0.2–3 mg/mL (free base basis)	Buffered acidic citrate strength + concentration window
4	Claim 3 + citrate 10 mM; concentration 0.3–1.2 mg/mL	Narrow citrate strength + concentration
5	Claim 4 + concentration 0.3–0.6 mg/mL	Narrowest concentration window
6	Claim 1 + salt used	Salt form included but not limited
7	Method claim: treat microbe-mediated diseases by administering claim 1 formulation	Indication is “microbe-mediated” (broad)
8	Claim 7 + IV administration	Route limitation
9	“Pharmaceutical composition” restating claim 1-type formulation	Product claim parallel
10	pH 4–5.5 + citrate buffer	Mid-range pH restriction
11	pH 4–5	Narrow pH restriction
12	pH about 5	Point pH limitation
13	citrate 10–20 mM	Buffer strength restriction
14	citrate 10 mM	Buffer strength point
15	vehicle: normal saline, 5% dextrose, or mixtures	Common infusion vehicles
16	pH 5 (tied to claims 3–5)	Target pH window
17	salt: acetate or L-lactate	Salt enumeration

What diseases are covered by the method-of-use claims in US 12,121,582?

How broad is the indication language?

Claim 7: “A method of treating diseases mediated by microbes” by administering claim 1 formulation.
Claim 8: same but IV administration.

The phrase “diseases mediated by microbes” is broad at the face of the claim. It likely covers:

bacterial, fungal, and potentially protozoal infections
infections where microbes drive disease pathophysiology

But the claim does not specify:

organism class
anatomical site (respiratory, urinary, bloodstream)
therapeutic endpoints
dosing frequency

Enforcement consequence
If a competitor markets the formulation for any microbial disease supported by labeling or promotional activity, the risk increases. If use is confined to non-microbial indications (rare given “microbe-mediated” breadth), method infringement would become harder.

How does US 12,121,582 handle salts, pH, and citrate buffer selection for design-around?

What are the key design-around “levers”?

Based on the claim limits, the main levers are:

Buffer identity
- Claim 1 requires citrate buffer.
- Moving to phosphate or histidine buffers avoids claim 1 on buffer identity grounds.
pH operating window
- Claim 1 requires buffered pH 4–6.
- Claim 10 requires 4–5.5; claim 11 4–5; claim 12 about 5.
- A formulation outside 4–6 avoids claim 1 even if citrate is used.
Citrate concentration (mM)
- Claim 3 requires citrate 10–20 mM.
- Claim 4/13/14 locks to 10 mM (and claim 14 also says citrate is 10 mM).
- A formulation using citrate at <10 mM or >20 mM may avoid claims 3–5/13–14 but still could infringe claim 1 if pH remains in 4–6.
Drug concentration in mg/mL
- Claim 3 imposes 0.2–3 mg/mL; claim 4 0.3–1.2 mg/mL; claim 5 0.3–0.6 mg/mL.
- Concentration-shifting can avoid narrower claims while leaving potential exposure to claim 1 (which does not require a drug concentration window).
Salt enumeration (acetate and L-lactate)
- Claim 17 restricts the salt to acetate or L-lactate.
- A competitor using a different pharmaceutically acceptable salt could avoid claim 17 while still potentially infringing claim 1/6 if salt status alone is enough.

Claim-by-claim “avoidance map” (high level)

Avoid claim 1: change buffer (non-citrate) or pH outside 4–6, or avoid using compound of formula (I).
Avoid claims 3–5: keep citrate but change citrate strength (<10 mM or >20 mM), pH outside 4–5.5, or shift concentration outside the specified windows.
Avoid claims 4/14: citrate not at 10 mM.
Avoid claim 15: use vehicles other than normal saline/5% dextrose/mixtures.

How many patents are likely in the US estate around US 12,121,582? What is the likely claim family structure?

No family-size inference can be made from claim text alone because the following are missing:

patent publication(s) and continuations
the identity of “compound of formula (I)” and its earlier filings
assignment chain, priority filings, and jurisdictional counterparts
whether this is a “formulation-only” continuation-in-part, or part of a broader composition-of-matter/indication package

Because the instruction requires complete and accurate response, the landscape cannot be quantified beyond the claim scope described above.

What patent expiration and exclusivity dates apply to US 12,121,582? When does it lose enforceability?

A reliable exclusivity/expiration timeline requires at minimum:

priority date(s)
filing date
whether any PTA (patent term adjustment) applies
whether terminal disclaimer(s) exist
whether there is any regulatory exclusivity tied to a specific FDA approval

The necessary data is not present in the prompt. No timeline is provided.

What is the Orange Book status of US 12,121,582 and how does it affect generic entry risk?

Orange Book listing status cannot be determined without:

drug name linked to “compound of formula (I)”
the Orange Book NDA/BLA identifier(s)
the listed patent numbers corresponding to that product

No Orange Book analysis is provided.

Which companies are challenging the formulation in Paragraph IV or generic litigation involving US 12,121,582?

Paragraph IV and litigation parties require:

court docket details
the asserted claims and the product at issue
the FDA ANDA/BLA numbers tied to US 12,121,582

No litigation mapping is possible from claim text alone. No parties are identified.

How does US 12,121,582 compare with typical injectable formulation patents: what is the novelty risk and what would be easy to copy?

Where the claim is comparatively “strong”

Buffer identity + pH: citrate buffer with pH 4–6 is a concrete formulation feature set.
Numeric narrowing in dependent claims: citrate strength and concentration windows can block close variants if an accused formulation matches those windows.

Where infringement can be harder to establish (practical risk)

If an accused formulation uses a non-citrate buffer while maintaining similar pH, claim 1 avoids.
If an accused formulation uses citrate but at different mM strength or different drug concentration, it may still avoid dependent claims and force reliance on claim 1 only.
If pH is managed such that the formulation is not within 4–6 “buffered” range (or if the measurement protocol becomes contested), the factual dispute becomes significant.

Does US 12,121,582 protect methods via IV administration for microbial diseases? What must a claimant prove?

For method claims (7–8), the typical infringement proof structure includes:

existence of a product that practices claim 1 formulation conditions
administration to a subject with a “diseases mediated by microbes” indication
administration via IV for claim 8

The claim language itself does not narrow to a specific dosing schedule. So proof likely depends on labeling and actual use evidence.

Commercial and regulatory risk framing for formulation competitors

If a competitor copies the formulation

Risk centers on matching:

citrate buffer
pH 4–6 (or narrower pH windows for claims 10–16)
drug concentration windows if trying to reach narrower claims

If a competitor designs around

Common pathways based on the claim structure:

switch buffer system away from citrate
shift pH outside 4–6
shift citrate mM away from 10–20 or away from 10 mM
shift concentration outside 0.2–3 mg/mL or the narrower dependent windows
switch salt form to avoid claim 17 while still possibly encountering claim 1/6

Key Takeaways

US 12,121,582 is a citrate-buffered injectable formulation patent centered on pH 4–6 and a compound of formula (I) (plus salt forms).
Dependent claims lock in citrate strength (10–20 mM, especially 10 mM) and drug concentration windows (0.2–3 mg/mL, narrowing to 0.3–1.2 and 0.3–0.6 mg/mL) and impose additional pH points (4–5, about 5, pH 5).
Method-of-use claims cover treatment of microbe-mediated diseases via administration of the claim 1 formulation, including IV.
The strongest design-around lever is replacing citrate buffer or moving pH outside 4–6; concentration and citrate mM are the main levers for avoiding dependent claim scopes.

FAQs

1) What counts as “citrate buffer” for infringement risk?

The claims require the formulation’s buffer to be citrate buffer. Any alternative buffering system avoids that limiting element.

2) Does the patent require a specific IV formulation excipient?

Not in claim 1. A pharmaceutically acceptable vehicle is required, but only claim 15 enumerates specific vehicle options.

3) If a competitor uses pH 5 citrate buffer but outside the mg/mL window, does it still infringe?

Claim 1 does not require the mg/mL concentration window. Numeric concentration limitations apply only to dependent claims (notably claims 3–5).

4) Do the method claims require a particular microbe type?

No. The claim language covers “diseases mediated by microbes” without specifying organism class.

5) Are acetate and L-lactate the only salts covered?

Claim 17 enumerates acetate and L-lactate, but claim 1 and claim 6 cover the compound as “a pharmaceutically acceptable salt” without limiting to those two salts.

References

US Patent 12,121,582 (claims as provided by user).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Hong Kong	XENLETA	lefamulin acetate	SOLUTION;INTRAVENOUS	211673-001	Aug 19, 2019		RX	Yes	Yes	12,121,582	⤷ 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
Australia	2016278774	⤷ Start Trial
Brazil	112017026904	⤷ Start Trial
Canada	2989372	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 12,121,582

Which drugs does patent 12,121,582 protect, and when does it expire?

Summary for Patent: 12,121,582