US Patent 10,588,893: Scope, Claim Boundaries, and US Landscape for Oxazole Ointment Formulations
US 10,588,893 claims an ointment formulation where an “oxazole compound represented by formula (11)” is formulated in a solvent system selected from ethylene carbonate, propylene carbonate, benzyl alcohol, and triacetin, with an ointment base that disperses or dissolves that solvent in an ointment vehicle. The claim set is tightly anchored to (i) the specific solvent list and (ii) quantitative solvent-to-oxazole and solvent-to-ointment-base ratios, plus (iii) optional vehicle characteristics (hydrocarbon; beeswax; unbleached beeswax) and (iv) droplet size limits when the solvent is dispersed as droplets.
What is the claim scope in plain terms?
Core independent claim (Claim 1): Oxazole in defined solvent(s) inside ointment base
Claim 1 requires all of the following:
- Product type: “An ointment”.
- Active class: an oxazole compound “represented by formula (11)”. The scope for which members fall inside that “formula (11)” depends on the definition and substitution pattern in the patent’s formula sheet (not provided here), but the claim language restricts the oxazole to that defined chemical class.
- Two-phase formulation logic:
- There is a solvent for dissolving the oxazole compound in the solvent.
- There is an ointment base for dispersing or dissolving the solvent in the ointment base.
- The oxazole compound is dissolved in the solvent.
- The solvent (once dissolved with oxazole) is then dispersed or dissolved in the ointment base.
- Solvent selection (must be at least one from a closed group):
- ethylene carbonate
- propylene carbonate
- benzyl alcohol
- triacetin
- No requirement that more than one solvent is used, because the claim is “at least one member selected from” the listed solvents.
Practical coverage implication: A generic “oxazole ointment” alone is not enough. To fall within Claim 1, the formulation must dissolve the oxazole in one of the listed solvents (or combinations including those solvents) and then incorporate that solvent-containing dissolved oxazole into an ointment base that disperses or dissolves that solvent.
How do dependent claims narrow scope and create infringement triggers?
Claim 2: Selects which solvent combinations are allowed
Claim 2 constrains Claim 1 by specifying that the solvent for dissolving the oxazole compound is selected from one of four options:
- (i) only ethylene carbonate
- (ii) only propylene carbonate
- (iii) ethylene carbonate with benzyl alcohol and/or triacetin
- (iv) propylene carbonate with benzyl alcohol and/or triacetin
Scope geometry:
- If the formulation uses benzyl alcohol + triacetin without either ethylene carbonate or propylene carbonate, it is outside this dependent claim (but may still fall under Claim 1, depending on whether Claim 1 requires one of the listed solvents only. Claim 1 already allows benzyl alcohol and triacetin as “at least one”; Claim 2 is a narrower pathway).
Claim 3: Quantitative solvent and ratio requirements
Claim 3 imposes a quantitative composition constraint:
- More than 2 parts by weight and 30 parts by weight or less of the solvent for dissolving the oxazole compound
per 1 part by weight of the oxazole compound
- And 5 to 5000 parts by weight of the ointment base
per 1 part by weight of the oxazole compound
This creates a clear infringement “band”:
- Too little solvent (≤ 2:1 solvent:oxazole) does not satisfy Claim 3.
- Too much solvent (> 30:1 solvent:oxazole) does not satisfy Claim 3.
- Ointment base outside 5:1 to 5000:1 relative to oxazole also fails Claim 3.
Coverage note: Claim 3 is dependent; it requires Claim 1 plus these quantitative limitations.
Claim 4: Vehicle includes a hydrocarbon
Claim 4 adds: “the ointment base comprises a hydrocarbon.”
This is an additional narrowing limitation. Formulations using non-hydrocarbon vehicles without a hydrocarbon component would not satisfy Claim 4.
Claims 5 and 8: Droplet-dispersed solvent mode and particle size limit
Claim 5 specifies a dispersion modality:
- The ointment base is “an ointment base for dispersing the solvent in the ointment base”
- The solvent “in the form of droplets”
- The oxazole compound is dissolved in the solvent and the solvent droplets are dispersed in the ointment base.
Claim 8 then sets a droplet size specification:
- “the droplets have a mean particle size of 100 μm or less.”
This establishes a manufacturing/process-linked boundary:
- A formulation that uses the same solvent logic but disperses droplets with a mean particle size above 100 μm would avoid Claim 8 (though it could still satisfy Claim 5 if droplet dispersion is used without the size cutoff).
Claims 6, 7: Beeswax content and “not chemically bleached”
Claim 6 adds: ointment base comprises at least beeswax.
Claim 7 adds: “the beeswax is not chemically bleached.”
Design-around leverage (conceptual): If a competitor omits beeswax entirely, they can avoid Claims 6 and 7. If they use beeswax but it is chemically bleached, they would not satisfy Claim 7 (while Claim 6 might still be met if beeswax is included regardless of bleaching status).
What is the practical claim set matrix (what combinations are actually covered)?
Below is a claim-by-claim “must-have” checklist derived from your claim text.
| Claim |
Additional limitations beyond the independent formulation |
Hard trigger elements |
| 1 |
Solvent must be at least one from {ethylene carbonate, propylene carbonate, benzyl alcohol, triacetin} and oxazole must be dissolved in that solvent |
Solvent list; oxazole dissolved in solvent; solvent incorporated into ointment base by dispersing or dissolving |
| 2 |
Solvent selection restricted to: only EC; only PC; EC + (benzyl alcohol and/or triacetin); or PC + (benzyl alcohol and/or triacetin) |
Which solvent combinations are permissible |
| 3 |
Quantitative: solvent 2–30 wt parts per 1 wt oxazole; ointment base 5–5000 parts per 1 wt oxazole |
Ratio boundaries |
| 4 |
Ointment base includes hydrocarbon |
Presence of hydrocarbon in vehicle |
| 5 |
Vehicle disperses solvent as droplets with oxazole dissolved in solvent |
Droplet dispersion mode |
| 6 |
Vehicle includes at least beeswax |
Beeswax presence |
| 7 |
Beeswax is not chemically bleached |
Beeswax processing/grade |
| 8 |
Droplet mean particle size ≤ 100 μm |
Droplet size specification |
What is the infringement-relevant “center of mass” of the patent?
For US enforcement and validity leverage, the strongest practical center is Claim 1 plus the solvent list and formulation logic. Claims 2, 3, 5, 6/7, and 8 define narrower formulation variants and can be used both ways:
- Plaintiff use: show the accused ointment meets the exact solvent selection and ratio/droplet/beeswax conditions.
- Defense use: target omission or deviation on any limiting element in a dependent claim.
The most “objective” and easiest-to-prove dependent limitations are usually:
- the solvent ratio band in Claim 3,
- the droplet size in Claim 8 (if droplet dispersion is used),
- and the presence/condition of beeswax in Claims 6-7.
How does this map to a typical US formulation patent landscape?
Likely competitive technology buckets that intersect with this claim set
Based on the claim structure alone, the patent sits at the intersection of:
- Topical ointment formulation patents (vehicle + droplet/dispersed solvent strategy)
- Solvent system selection patents (the solvent list constraint is unusually specific in claims)
- Active solubility enablement (oxazole dissolved in a defined solvent prior to vehicle incorporation)
- Microstructure-controlled formulations (droplet mean particle size ≤ 100 μm)
Key landscape reality: narrow solvent list can still create broad “design space” coverage
Even with a closed solvent list, Claim 1 allows:
- ethylene carbonate OR propylene carbonate OR benzyl alcohol OR triacetin, plus combinations.
That can still cover many formulation pathways because an ointment can be structured to dissolve the active in one solvent and then disperse that solvent phase in a vehicle.
Most common design-around paths based on claim language
Without relying on hypothetical chemistry, the claim text itself suggests these avoidance vectors:
- Use an oxazole compound but dissolve it in a solvent not in {ethylene carbonate, propylene carbonate, benzyl alcohol, triacetin} (evades Claim 1).
- Keep those solvents but violate dependent claim boundaries if that claim is asserted:
- solvent amount outside 2–30 parts per part oxazole (Claim 3),
- droplet mean particle size above 100 μm (Claim 8),
- omit beeswax (Claims 6-7),
- use chemically bleached beeswax (Claim 7).
- Use the same solvent logic but do not disperse as droplets (avoids Claim 5 and 8).
What can be concluded about the scope of “oxazole compound represented by formula (11)” from the claim text alone?
The claim is chemically limiting: “oxazole compound represented by the following formula (11).” Without the formula definition text, the claim scope can only be described structurally:
- Only oxazole species that fit formula (11) are within the claimed active class.
- Oxazole derivatives outside formula (11) are outside the claims even if they are soluble in the same solvents.
Thus, the patent landscape impact has two axes:
- Formulation axis (solvent list, ratios, vehicle requirements)
- Chemical axis (whether the oxazole candidate is actually within formula (11))
Is the claim set structured for broad or narrow enforceability?
The structure is mixed:
- Broad element: Claim 1 covers any ointment using any of the listed solvents to dissolve the specific oxazole and then incorporate that solvent-containing solution into an ointment base that disperses or dissolves it.
- Narrow elements: dependent claims add hard constraints (ratio band; droplet size; beeswax type; hydrocarbon presence).
This is typical of formulation patents where the independent claim captures the general enablement approach, and dependent claims lock in practical formulation variants for stronger evidentiary proof at trial.
US patent landscape: what to map for freedom-to-operate (FTO)
A correct US landscape mapping for 10,588,893 requires identifying:
- Immediate claim family members (continuations/divisionals) that may carry the same solvent and vehicle logic with different limitations.
- Related formulation patents from the same applicant where oxazole actives are paired with these solvent systems and ointment bases.
- Competing formulation patents that use the same droplet/dispersed solvent approach but with different solvent lists or different solvent ratio bands.
- Litigation or reexamination events involving the same claim concepts (solvent phase carriers, droplet size, beeswax vehicle constraints).
However, your request asks for “patent landscape” for US 10,588,893 specifically. The claim text you provided is sufficient to parse scope mechanics, but not sufficient to enumerate citations, cite prior art, or list specific US patents/assignees in the landscape without introducing unsupported assertions. Under strict analysis constraints, this response therefore limits itself to the scope boundaries inherent in the claims you supplied.
Key Takeaways
- US 10,588,893 Claim 1 is driven by a closed solvent list: at least one of ethylene carbonate, propylene carbonate, benzyl alcohol, triacetin, where the oxazole (formula (11)) is dissolved and then incorporated into an ointment base that disperses or dissolves the solvent.
- Dependent claims create enforceable “gates”:
- solvent amount band in Claim 3 (>2 and ≤30 wt parts solvent per 1 wt oxazole; ointment base 5 to 5000 per 1 wt oxazole),
- droplet dispersion and droplet size (mean ≤100 μm) in Claims 5 and 8,
- vehicle composition constraints (hydrocarbon in Claim 4; at least beeswax in Claim 6; not chemically bleached beeswax in Claim 7).
- The most practical design-arounds, based on claim text, are: exclude the claimed solvent list, use solvent ratios outside Claim 3’s band, avoid droplet dispersions with mean particle size ≤100 μm, or omit/alter beeswax characteristics where those dependent claims are asserted.
FAQs
1. What is the single most important limitation in Claim 1?
The solvent for dissolving the oxazole must be selected from the group: ethylene carbonate, propylene carbonate, benzyl alcohol, and triacetin, with the oxazole dissolved in that solvent prior to incorporation into the ointment base.
2. Can a formulation that uses benzyl alcohol and triacetin avoid Claim 2 but still meet Claim 1?
Yes in principle: Claim 2 restricts solvent options to those tied to ethylene carbonate or propylene carbonate, while Claim 1 allows “at least one” from the full solvent list.
3. How does Claim 3 constrain formulation concentration?
It requires solvent amounts of more than 2 parts by weight and up to 30 parts by weight per 1 part by weight of oxazole, and ointment base at 5 to 5000 parts by weight per 1 part by weight of oxazole.
4. What does Claim 8 protect that Claim 5 alone does not?
Claim 8 adds a quantitative droplet size requirement: mean particle size must be 100 μm or less.
5. Is beeswax legally irrelevant if the competitor does not use droplets?
No. Beeswax constraints are in Claims 6 and 7, which are independent of the droplet mode. Droplet avoidance does not automatically eliminate those dependent claim requirements if the beeswax limitations are met.
References
[1] US Patent 10,588,893 (claims excerpt as provided).
