Scope and Claims of US Patent 11,717,555 and the U.S. Patent Landscape for Acid Salt/Polymer/NMP Controlled-Release LHRH Agonist Formulations
US Patent 11,717,555 is a formulation patent that narrows heavily on (i) an LHRH agonist existing as a specific pairing of strong-acid and weak-acid salts defined by molar anion-to-drug ratios, (ii) a biodegradable polymer choice restricted to PLA or specified-end and specified-chemistry PLGA ranges, and (iii) N-methyl-2-pyrrolidone (NMP) as a component, with controlled release duration mapped to those anion ratios. The claims further crystallize into leuprolide-specific embodiments (including leuprolide mesylate plus leuprolide acetate or leuprolide formate) and additional constraints on polymer hydroxyl terminals, polymer content window, polydispersity, and polymer molecular weight.
Below is a claim-by-claim scope analysis and a practical U.S. landscape map for competitive freedom-to-operate (FTO), generic/LAUNCH risk, and possible workarounds.
What does US 11,717,555 claim: strong-acid/weak-acid salt combinations with PLA/PLGA and NMP for 1-to-6 month LHRH agonist release?
Featured snippet answer: The independent claim (claim 1) requires an LHRH agonist (leuprolide, triptorelin, or goserelin) formulated as a mixture of strong-acid salt and weak-acid salt in defined molar ratio windows, combined with PLA or PLGA with lactic:glycolic between 50:50 and 100:0 plus NMP, where selected release duration (1 to 6 months) correlates with the anion ratio.
Claim 1 element breakdown (infringement “all elements” framework)
A. LHRH agonist and its salt system
- LHRH agonist: one of leuprolide, triptorelin, goserelin
- Strong acid salt anion source: methanesulfonic acid (mesylate) or hydrochloric acid (chloride)
- Weak acid salt anion source: acetic acid (acetate) or formic acid (formate)
- Salt pairing: combination of strong acid salt + weak acid salt of the same LHRH agonist.
- Ratio constraints (core novelty driver):
- (strong anion + weak anion) : LHRH agonist ≤ 2:1
- strong anion : LHRH agonist 1:1 to < 2:1
B. Biodegradable polymer
- Polymer is limited to one of:
- Homopolymer polylactic acid (PLA), or
- PLGA (poly(lactic acid-co-glycolic acid))
- If PLGA: lactic acid : glycolic acid is 50:50 to 100:0 (covers 50/50 up to near 100/0).
C. NMP
- N-methyl-2-pyrrolidone is included as an ingredient.
D. Controlled release duration mapping to salt ratios
- Composition is characterized by a selected release duration from 1 month to 6 months
- The claim requires that this release duration correlates with ratios of the strong-acid anion and weak-acid anion.
E. Practical meaning
In practice, claim 1 is not just “includes PLA/PLGA and NMP.” It forces a tight coupling between:
- salt identity (mesylate or chloride; acetate or formate),
- numeric molar anion ratios,
- polymer selection/range (PLA or specific PLGA compositions),
- and release target (1-6 months), tied to those salt ratios.
This is the kind of claim that is difficult to design around without changing at least one of: salt pairing, ratio windows, polymer chemotype/range, NMP inclusion, or release profile coupling.
How do the dependent claims narrow US 11,717,555: leuprolide-only embodiments, specific acid pairs, and polymer constraints?
Claim 2 (LHRH agonist limited)
- LHRH agonist is leuprolide (vs triptorelin or goserelin).
Claim 3 (strong acid limited)
- Strong acid is methanesulfonic acid (i.e., strong salt is mesylate).
Claim 4 (weak acid limited)
- Weak acid is formic acid (i.e., weak salt is formate).
Claim 5 (specific salt pair)
- Strong acid salt = leuprolide mesylate
- Weak acid salt = leuprolide acetate
- Note the pairing here is mesylate + acetate, not mesylate + formate.
Claims 6 and 7 (mesylate-to-leuprolide anion ratio windows)
- Claim 6: mesylate anion : leuprolide is 1.4:1 to < 2:1
- Claim 7: mesylate anion : leuprolide is 1.5:1 to 1.8:1
These windows matter because claim 1 already sets strong anion between 1:1 and <2:1. Claims 6/7 narrow further into the high-confidence region.
What is claim 8: leuprolide mesylate plus leuprolide formate with correlated 1–6 month release, PLA/PLGA, and NMP?
Featured snippet answer: Claim 8 is the leuprolide-specific salt pairing of leuprolide mesylate + leuprolide formate, with explicit molar ratio constraints, plus PLA or specified PLGA, plus NMP, with a 1–6 month release duration correlated to the mesylate-to-leuprolide ratio.
Claim 8 element breakdown
- A. Salt combination
- Combination: leuprolide mesylate + leuprolide formate
- (mesylate + formate) : leuprolide ≤ 2:1
- mesylate anion : leuprolide 1:1 to <2:1
- B. Polymer
- PLA or PLGA
- PLGA lactic:glycolic 50:50 to 100:0
- C. NMP
- D. Release duration correlation
- selected release duration 1 month to 6 months
- correlates with mesylate to leuprolide ratios (strong-acid component emphasis)
Claims 9 and 10 (tighter mesylate ratio windows)
- Claim 9: mesylate anion : leuprolide 1.4:1 to <2:1
- Claim 10: 1.5:1 to 1.8:1
Claim 11–13 (polymer hydroxyl terminal group requirement)
- Claim 11: claim 1 with polymer having at least one hydroxyl terminal group
- Claim 12: claim 5 with hydroxyl terminal group polymer
- Claim 13: claim 8 with hydroxyl terminal group polymer
This can be a meaningful constraint because polymer end-group chemistry affects moisture uptake, degradation kinetics, microenvironment pH, and release.
What are claims 14 and 15: polymer loading, polydispersity, and molecular-weight limits?
Claim 14
- Composition contains 30 to 60% biodegradable polymer by weight
- Polymer polydispersity ≤ 2.5
Claim 15
- Polymer average molecular weight 8,000 to 50,000 Daltons
These constraints create a narrower formulation “process outcome” space. Even if a product uses mesylate/acetate or mesylate/formate with PLA/PLGA and NMP, it may avoid infringement if:
- polymer loading is outside 30–60 wt%,
- polymer polydispersity exceeds 2.5,
- or polymer molecular weight is outside 8,000–50,000 Da.
What is the claim scope for each competitor-relevant design-around lever?
The claim is structurally tight. Below are the main freedom-to-operate levers implied by the claim language.
1) Salt pairing and which weak acid anion is used
- Claim 1 allows:
- strong: mesylate or chloride
- weak: acetate or formate
- Claim 5 locks to mesylate + acetate (leuprolide).
- Claim 8 locks to mesylate + formate (leuprolide).
Design-around implication: switching the weak acid counterion (acetate ↔ formate) can move you off claims 5/8, but still could fall under claim 1 unless you also leave the allowed ratio windows or change other elements.
2) Strong-acid anion molar ratio windows
- Claim 1 strong anion : LHRH ≤ (1:1 to <2:1) and combined salts : drug ≤ 2:1.
- Claim 6/7 and 9/10 narrow mesylate windows to 1.4–<2 and 1.5–1.8.
Design-around implication: a formulation using a mesylate:leuprolide ratio below 1.4 or at/above 2.0 (if that is chemically feasible) could reduce risk. The “≤2:1 combined salts” language also constrains total anion equivalents.
3) Polymer selection: PLA vs PLGA and PLGA lactic:glycolic band
- Claim 1: polymer is PLA or PLGA with lactic:glycolic 50:50 to 100:0.
Design-around implication: using a PLGA outside that band (e.g., glycolide-rich outside 50:50) could avoid claim 1, but only if the polymer is not “within” the numeric band under testing.
4) NMP inclusion
- Claim 1 requires NMP.
- No dependent claim removes or modifies NMP.
Design-around implication: excluding NMP, or replacing it with another solvent/excipient system, is a straightforward avoidance path if the claim requires NMP as a component.
5) Release duration linkage to anion ratios (the correlation requirement)
The claim requires that the selected release duration (1 to 6 months) correlates with the strong/weak anion ratios.
Design-around implication: even if you match the ratio windows, you still need the “correlates with” limitation to be satisfied in the accused product’s characterization. That said, in a litigation posture, correlation language often becomes a claim-construction and proof-of-characteristics issue.
6) Polymer hydroxyl terminals and polymer physical specs
- Hydroxyl terminal group: claim 11–13.
- Polymer loading: 30–60 wt% (claim 14).
- Polydispersity ≤ 2.5 (claim 14).
- Molecular weight 8,000–50,000 Da (claim 15).
Design-around implication: changing polymer end groups or polymer specifications can remove claim 11–15 without changing the salts or solvent.
How many distinct embodiments does US 11,717,555 cover based on claim structure?
At minimum, the independent-claim family includes:
- Generic independent scope (claim 1): LHRH agonist ∈ {leuprolide, triptorelin, goserelin}, strong anion ∈ {mesylate, chloride}, weak anion ∈ {acetate, formate}, PLA or PLGA 50:50–100:0, NMP, 1–6 month correlated release, numeric ratio limits.
- Leuprolide-specific salt pairing embodiment with mesylate+formate (claim 8).
- Leuprolide mesylate+acetate embodiment (claim 5) plus tighter ratio windows (claims 6/7).
- Sub-embodiments layered with polymer hydroxyl terminals (claims 11–13).
- Sub-embodiments layered with polymer loading/polydispersity/MW (claims 14–15).
This is a multi-layer “stack” claim set: multiple dependent claims narrow within the same formulation space.
What does this patent likely target in the commercial landscape: controlled-release LHRH depot products and PLGA/PLA depot tech?
US 11,717,555 reads like an effort to claim differentiation within common depot-technology building blocks used across LHRH agonist products (e.g., microspheres/implants based on biodegradable polymers). The differentiators are:
- two-salt combination (strong + weak acid salts of the same LHRH agonist),
- defined anion equivalent ratio windows,
- NMP inclusion,
- and tight polymer property/chemistry constraints (PLA or specific PLGA band, hydroxyl terminal, loading/polydispersity/MW).
In an FTO context, the “attack surface” is not all LHRH depot products. It is those that:
- use this specific strong/weak acid salt pairing,
- use NMP,
- use PLA or 50:50–100:0 PLGA,
- and hit the numeric ratio windows and release-duration correlation.
What patent landscape typically surrounds US 11,717,555 in the U.S.: how to think about related claims likely present nearby?
Even without external file data, the claim form suggests the patent estate around it will usually include:
- earlier composition-of-matter patents on LHRH agonist salts (including specific mesylate/acetate/formate salts),
- earlier depot formulation patents on leuprolide depot using PLA/PLGA,
- process patents on solvent casting/particle formation using NMP or NMP-containing steps,
- and later formulation patents that tune salt ratios and polymer molecular weight/end groups to achieve particular release durations.
Practical consequence: In U.S. litigation or an ANDA/505(b)(2) design, the main risk is not only whether the accused product uses PLA/PLGA depot, but whether it matches the acid salt ratio logic and NMP presence. Many generics will be forced into a “different solvent system” or “different salt system” to keep outside narrow ratio and ingredient limitations.
Key Takeaways
- US 11,717,555 is formulation-centric with a tight “salt ratio + polymer chemotype + NMP + release-duration correlation” claim logic.
- The strongest claim scope is claim 1, with major narrowing for leuprolide mesylate+acetate (claim 5) and leuprolide mesylate+formate (claim 8) plus specific mesylate ratio windows.
- NMP is required, so replacing it is a primary design-around path.
- Polymer properties (hydroxyl terminals, loading 30–60 wt%, PDI ≤2.5, MW 8,000–50,000 Da) create additional escape routes if the formulation targets are met differently.
- Risk concentrates in products that match:
- salt pairing (mesylate/chloride with acetate/formate),
- numeric anion-to-drug ratios,
- PLA or PLGA with 50:50–100:0,
- and 1–6 month release targets tied to those ratios.
FAQs
1) Does US 11,717,555 cover depot formulations without NMP?
No. Claim 1 requires NMP as a component; dependent claims maintain that requirement.
2) If a product uses leuprolide mesylate and leuprolide acetate but outside 1.4–<2.0 mesylate ratio, is it still covered by claims 5–7?
Claims 6 and 7 would not be met. Claim 1 may still be implicated if the broader ratio conditions and other elements align.
3) Can a formulation use PLGA with a lactic:glycolic ratio below 50:50 to avoid claim 1?
That would fall outside claim 1’s permitted PLGA band (50:50 to 100:0), assuming the polymer is tested and characterized to be outside the range.
4) Are hydroxyl terminal-group polymers required for all infringement?
No. Hydroxyl terminals are in dependent claims (11–13). Claim 1 does not require hydroxyl terminals.
5) What parameter is most likely to be tuned for a generic to reduce infringement risk?
Salt identity and anion molar ratios, plus NMP inclusion and polymer physical specs (loading, PDI, MW).
References
No external patent documents or prosecution/Orange Book records were provided in the prompt beyond the claim text for US 11,717,555; therefore no additional sources can be cited.
