United States Patent 10,376,538 (US10376538): Scope, Claim-by-Claim Readout, and Patent Landscape
What does US 10,376,538 claim cover at the product level?
US 10,376,538 claims topical compositions built around nitric oxide (NO)-releasing polysiloxane macromolecules and gel bases designed to preserve NO at room temperature after formulation.
Core claimed architecture (Claims 1 and 13)
- NO-releasing polysiloxane macromolecules
- Made by co-condensation of:
- at least one aminoalkoxysilane
- an alkoxysilane
- Gel base
- Claim 1: hydrophobic, non-aqueous gel base comprising mineral oil
- Claim 13: hydrophilic gel base comprising an alcohol
- NO retention requirement
- “At least 70% of NO remains” in the topical composition
- Measured two days after initial formulation
- Stored at room temperature
This “NO retention after formulation” constraint is the functional crux that narrows the scope beyond “NO-releasing topical gels.”
Stronger NO retention dependent language (Claims 10 and 20)
- Claim 10: at least 80% NO remains after two days at room temperature
- Claim 20: same 80% requirement for the hydrophilic variant
Product composition concentration range (Claims 2 and 14)
- 0.1% to 20% by weight of NO-releasing polysiloxane macromolecules
- Claim 2 applies to the mineral-oil/hydrophobic base
- Claim 14 applies to the alcohol/hydrophilic base
Particle/hydrodynamic size limits (Claims 7-8 and 17-18)
Two size bands appear in the claim set:
- 1000 nm to 10 microns (Claims 7 and 17)
- 1 nm to 100 nm (Claims 8 and 18)
These are drafted as alternative ranges within dependent claims, not as a single consistent parameter, which can widen practical coverage depending on claim construction.
How broad is the gel-base scope? (hydrophobic vs hydrophilic)
US 10,376,538 partitions the invention into two composition “families”:
Hydrophobic, non-aqueous gel base family (Claim 1)
-
Base includes mineral oil as a required component
-
Additional dependent options:
- Silicone gel (Claim 3)
- Petrolatum (Claim 4)
- Polyethylene (Claim 32)
-
Mineral oil concentration constraint (Claim 5)
-
Hydrophobic content thresholds (Claims 11-12)
- Claim 11: total hydrophobic components ≥ 49% by weight
- Claim 12: total hydrophobic components ≥ 80% by weight
The combination of “mineral oil” plus hydrophobicity thresholds supports an argument that the gel system must remain strongly non-aqueous and lipophilic to protect NO.
Hydrophilic gel base family (Claim 13)
-
Base includes an alcohol (required)
-
Alcohol concentration constraints (Claims 21-22)
- at least 60% by weight (Claim 21)
- 60% to 90% by weight (Claim 22)
-
Alcohol identity variants:
- isopropyl alcohol (Claim 23)
- ethanol (Claim 33)
-
Specific hydrophilic gelling agent (Claims 24-25)
- hydroxypropyl cellulose required if Claim 24 is selected
- concentration 0.75% to 2.5% by weight (Claim 25)
-
Partition coefficient limitation for gel excipients (Claim 16)
- octanol/water partition coefficient (Kow) of:
- gel excipients and NO-releasing polysiloxane macromolecules
- within −2 to 0
This Kow restriction is a chemical specificity lever, tying the excipient selection to hydrophilic behavior that may reduce NO loss.
What additional formulation constraints are claimed?
Beyond gel base and NO retention, the patent includes targeted dependent claims that narrow excipient selection and compatibility.
Octanol/water partition coefficient range (Claim 6)
- For hydrophobic gel version:
- octanol/water partition coefficient 0.1 to 7
- applies to “gel excipients and the NO-releasing polysiloxane macromolecules”
Gel/base “hydrodynamic radius” (Claims 7-8 and 17-18)
As noted, size bands are included twice with different ranges, which can matter for:
- nanoparticle/macromolecule formation
- formulation consistency
- measured hydrodynamic behavior depending on assay method
Optional co-therapeutics (Claims 9, 19)
The topical composition can include:
- anti-acne agent
- antimicrobial agent
- benzoyl peroxide
- corticosteroid
The claim is written broadly as “further comprising” these categories, meaning infringement risk increases if an accused product blends NO-releasing polysiloxane gels with common acne and anti-microbial actives.
What do the method claims cover?
US 10,376,538 ties the compositions to use.
Methods of treatment by topical application
- Wounds:
- apply Claim 1 composition (Claim 27)
- apply Claim 13 composition (Claim 28)
- Burns:
- apply Claim 1 composition (Claim 29)
- Acne:
- apply Claim 1 composition (Claim 30)
- apply Claim 13 composition (Claim 31)
There is no explicit limitation on severity, chronicity, or lesion type in the method claims. The scope turns on whether the applied topical matches the claimed composition.
Claim-by-claim scope summary (what is required vs optional)
Independent claims
-
Topical composition (hydrophobic/mineral oil)
- Required:
- NO-releasing polysiloxane macromolecules made by aminoalkoxysilane + alkoxysilane co-condensation
- hydrophobic non-aqueous gel base with mineral oil
- NO retention: ≥70% after 2 days at room temperature
- Required structure/composition constraints embedded in dependent claims (if asserted)
-
Topical composition (hydrophilic/alcohol)
- Required:
- same NO-releasing polysiloxane co-condensation concept
- hydrophilic gel base with alcohol
- NO retention: ≥70% after 2 days at room temperature
Key dependent claim “narrowers”
- Amount of polysiloxane macromolecules: 0.1% to 20% (Claims 2, 14)
- NO retention level: ≥80% (Claims 10, 20)
- Gel base specific excipients:
- mineral oil %: 10% to 90% (Claim 5)
- silicone gel (Claim 3)
- petrolatum (Claim 4)
- polyethylene (Claim 32)
- Hydrophobic fraction:
- ≥49% (Claim 11) or ≥80% (Claim 12)
- Alcohol formulation specifics:
- 60% to 90% alcohol (Claim 22)
- isopropyl alcohol (Claim 23)
- ethanol (Claim 33)
- hydroxypropyl cellulose presence and % (Claims 24-25)
- Partition coefficient ranges:
- hydrophobic: 0.1 to 7 (Claim 6)
- hydrophilic: −2 to 0 (Claim 16)
- Particle size bands:
- hydrophobic: 1000 nm to 10 microns (Claim 7) or 1 nm to 100 nm (Claim 8)
- hydrophilic: 1000 nm to 10 microns (Claim 17) or 1 nm to 100 nm (Claim 18)
- Add-on actives (Claims 9, 19)
- acne agents, antimicrobials, benzoyl peroxide, corticosteroids
How does this shape the competitive patent landscape?
What you are really licensing or designing around
US 10,376,538 is not merely “NO-releasing polysiloxane topical.” It claims:
- The polysiloxane NO-releasing macromolecule scaffold (aminoalkoxysilane + alkoxysilane co-condensation)
- The gel base class (mineral oil hydrophobic vs alcohol hydrophilic)
- A NO retention performance threshold after formulation (70% at two days room temp; 80% in narrower dependents)
- Certain formulation physics/chemistry guardrails (partition coefficient ranges, hydrodynamic radius bands, concentration ranges)
That combination tends to create high design-around friction because competitors must match performance and composition conditions, not only the general concept of NO release.
Practical infringement risk mapping (by product type)
- If a competitor sells an NO-releasing topical gel using polysiloxane-type NO donors:
- Highest risk if the gel base matches:
- mineral-oil hydrophobic non-aqueous system with similar NO retention
- or alcohol-based hydrogel with similar NO retention
- Risk rises if the competitor’s formulation includes:
- mineral oil at 10% to 90%
- hydrophobic component totals above 49% or 80%
- excipients with Kow in the claimed ranges
- polysiloxane concentration within 0.1% to 20%
- measured hydrodynamic radius in the claimed ranges
- If a competitor changes only the therapeutic use (acne, wounds, burns) while keeping the same composition:
- Method claims (27-31) increase the chance of use-based infringement if the topical product meets composition claims.
Likely landscape clusters (invention categories you should benchmark)
Even without enumerating every citing or related patent in the record, US 10,376,538 positions the field into four crowded zones:
- NO-releasing polysiloxanes (macro-structure and donor chemistry)
- Topical NO stability/formulation engineering (retention after storage)
- Non-aqueous and alcohol gel bases for dermal delivery
- Combination products for dermatology (benzoyl peroxide, corticosteroids, antimicrobial actives)
In portfolio terms, US 10,376,538 is strongest where competitors commercialize “NO gel + standard dermatology actives” because those “further comprising” elements broaden the device around which an infringing composition can form.
Where the claim language concentrates enforceable scope
The NO retention test is the core constraint
The claims require at least:
- 70% NO retention after two days at room temperature (Claims 1, 13)
- 80% in narrower dependents (Claims 10, 20)
For freedom-to-operate, this implies an accused product must demonstrate comparable NO retention under comparable testing conditions. Products that lose NO faster due to solvent volatility, donor instability, or excipient-driven quenching are less likely to match.
Gel-base selection is also a hard boundary
- Mineral oil is required for the hydrophobic independent claim.
- Alcohol is required for the hydrophilic independent claim.
- The patent also imposes concentration windows and hydrophobic fraction limits in dependent claims.
The donor scaffold is narrowly described by co-condensation
The polysiloxane macromolecules are defined by:
- co-condensation of aminoalkoxysilane and alkoxysilane
That definition tends to exclude unrelated NO donor chemistries (e.g., S-nitrosothiols not built into a polysiloxane macromolecular network).
Key takeaways
- US 10,376,538 claims two topical composition families: mineral-oil hydrophobic and alcohol hydrophilic, each built on aminoalkoxysilane + alkoxysilane co-condensation NO-releasing polysiloxane macromolecules.
- Both independent claims are anchored to NO retention: at least 70% NO remains after two days at room temperature; dependents tighten this to 80%.
- The strongest narrowing features that drive infringement or design-around are:
- gel base identity (mineral oil vs alcohol)
- polysiloxane loading (0.1% to 20% by weight)
- mineral oil % (10% to 90%) and hydrophobic fraction thresholds (≥49% or ≥80%)
- alcohol % (≥60% or 60% to 90%) and gelling agent hydroxypropyl cellulose (0.75% to 2.5%)
- octanol/water partition coefficient ranges (hydrophobic: 0.1 to 7; hydrophilic: −2 to 0)
- hydrodynamic radius ranges (two alternative bands in each family)
- Method coverage extends to wounds, burns, and acne via application of the claimed compositions.
FAQs
1) Does US 10,376,538 require the topical product to be an acne treatment?
No. The composition claims are general topical compositions; acne appears in separate method claims (Claims 30-31) where the claimed topical is applied to treat acne.
2) What is the performance metric competitors must hit to match the independent claims?
The claims require that at least 70% of NO remains after two days at room temperature in the topical composition.
3) Can an infringing product use an alcohol gel instead of mineral oil gel?
Yes, if it matches the hydrophilic independent claim (Claim 13): NO-releasing polysiloxane macromolecules in an alcohol-based gel base with the same ≥70% NO retention after two days at room temperature.
4) Are benzoyl peroxide and corticosteroids mandatory?
No. Claims 9 and 19 are “further comprising” language, so inclusion increases the chance of covering combination formulations but is not required for the independent claim.
5) Do the dependent claims about hydrodynamic radius narrow the core invention?
They narrow specific dependent claim sets (Claims 7-8 and 17-18). The independent claims do not explicitly state a hydrodynamic radius limit in the text provided, but size-based dependent claims can still control the enforceable scope for certain formulations.
References
[1] United States Patent and Trademark Office. “US 10,376,538.” (Bibliographic and claims record).
