US Patent 11,540,981: Topical 5-ALA Gel With Nanoemulsion (Oil-in-Water) Scope, Claim Boundaries, and Landscape
What is the protected invention in US 11,540,981?
US 11,540,981 claims a topical gel composition for delivering 5-aminolevulinic acid hydrochloride (5-ALA·HCl), where the formulation is defined by a specific gel matrix (xanthan gum and preservatives including propylene glycol) plus a specific nanoemulsion system (oil-in-water nanoemulsion with soy lecithin and polysorbate 80, triglyceride oil phase, isopropyl alcohol, and phosphate buffer) having nanometer-scale particle dimensions.
The core inventive footprint is the combination of:
- 5-ALA·HCl at 3-15% w/w (preferred embodiments recite ~10% w/w)
- xanthan gum at 1-3% w/w (one dependent set uses 2-3% w/w)
- At least two preservatives at 1-3% w/w, where one is propylene glycol (dependent claim set allows “at least one” preservative, propylene glycol-based)
- A nanoemulsion with tightly bounded composition ranges and particle-size metrics prior to incorporation into the gel:
- Nanoemulsion is oil-in-water
- Water 50-98% w/w (claim 10 uses 70-95%)
- Surfactant + co-surfactant 1-30% w/w, where:
- surfactant is soy lecithin
- co-surfactant is polysorbate 80
- Triglycerides 0.1-15% w/w (claim 4 narrows to 1-8%; claim 10 narrows to 0.1-1%)
- Isopropyl alcohol 1-2% w/w
- Phosphate buffer 5-30 mM
- Mean particle diameter 5-35 nm, with standard deviation about 5 nm
- Several dependent claims lock specific numeric preferences (10% 5-ALA·HCl; nanoemulsion 10-30% w/w; triglyceride subranges; lecithin phosphatidylcholine content at least 90% w/w)
How broad are the independent claim boundaries (Claim 1, Claim 6, Claim 10)?
Claim 1 (key independent scope)
Claim 1 covers a topical gel composition having the following structural limits:
(A) 5-ALA·HCl in gel
- 3-15% w/w 5-aminolevulinic acid hydrochloride
(B) Gel thickener
(C) Preservatives
- 1-3% w/w of at least two preservatives
- one preservative is propylene glycol
(D) Nanoemulsion added to gel
Nanoemulsion must be:
- Oil-in-water
- Composition bounds (as % of the nanoemulsion, not the gel):
- Water: 50-98% w/w
- Surfactant + co-surfactant: 1-30% w/w
- surfactant: soy lecithin
- co-surfactant: polysorbate 80
- Triglycerides: 0.1-15% w/w
- Isopropyl alcohol: 1-2% w/w
- Phosphate buffer: 5-30 mM
- Particle constraints:
- Mean diameter 5-35 nm
- Standard deviation about 5 nm
- Particle constraints must be met “prior to incorporation into the topical gel composition.”
This language matters for infringement: even if the final gel shows different behavior after mixing, the claim is anchored to the nanoemulsion’s size distribution before incorporation.
Claim 6 (independent refinement set)
Claim 6 materially overlaps Claim 1 but locks multiple preferences:
- Gel composition includes:
- about 10% w/w 5-ALA·HCl
- 1-3% xanthan gum
- 1-3% by weight of at least two preservatives with propylene glycol included
- Nanoemulsion bounds match Claim 1 in general structure:
- Water 1? (Claim 6 uses “water” with the earlier ranges; the dependent language in your text sets the nanoemulsion to soy lecithin + polysorbate 80, triglycerides 0.1-15%, isopropyl alcohol 1-2%, phosphate buffer 5-30 mM)
- Adds a lecithin purity/identity limitation:
- soy lecithin has phosphatidylcholine content at least 90% by weight
It also includes the same particle size and standard deviation requirements.
Claim 10 (independent refinement set)
Claim 10 is the most specific oil-phase burdening and water window:
- Gel:
- about 10% w/w 5-ALA·HCl
- 2-3% xanthan gum
- 1-3% by weight of at least one preservative, where the preservative comprises propylene glycol
- nanoemulsion present in the gel (no numeric gel wt% is stated in your claim text for Claim 10)
- Nanoemulsion:
- Water 70-95% w/w
- surfactant + co-surfactant about 1% by weight
- soy lecithin + polysorbate 80 together at about 1%
- triglycerides 0.1-1% w/w
- isopropyl alcohol 1-2% w/w
- phosphate buffer 5-30 mM
- Particle mean 5-35 nm, SD about 5 nm
From a freedom-to-operate perspective, Claim 10 is a sharper target for products that use very low triglyceride content and very low total surfactant load (about 1%) while still achieving 5–35 nm droplet sizes.
What exactly is the claim “hook” that differentiates from generic 5-ALA gels?
US 11,540,981’s claim construction makes the nanoemulsion system the distinguishing element, not the 5-ALA or the gel polymer alone.
The claim “hook” is the combination of:
- Nanoemulsion particle size: mean 5-35 nm with standard deviation about 5 nm
- Specific formulation chemistry:
- oil phase: triglycerides
- surfactant system: soy lecithin + polysorbate 80
- cosolvent: isopropyl alcohol 1-2%
- buffer: phosphate buffer 5-30 mM
- Placement requirement: nanoemulsion particle size is defined prior to incorporation
- Constrained gel adjuncts: xanthan gum and propylene glycol-preservative system in specified wt ranges
A product that matches 5-ALA wt% and xanthan gum but uses a different nanoemulsion oil type, surfactant pair, or particle size profile would fall outside the strict claim language.
Dependent claim narrowing map (numerical fences and how they stack)
Key dependent parameters stated in your claim set
| Parameter |
Claim 1 |
Claim 2 |
Claim 3 |
Claim 4 |
Claim 5 |
Claim 6 |
Claim 7 |
Claim 8 |
Claim 9 |
| 5-ALA·HCl in gel |
3-15% |
“about 10%” |
- |
- |
- |
about 10% |
about 10% |
about 10% (via Claim 6) |
about 10% (via Claim 6) |
| Xanthan gum in gel |
1-3% |
- |
- |
- |
- |
1-3% |
- |
- |
- |
| Nanoemulsion in gel (wt%) |
not stated in Claim 1 text |
- |
10-30% |
- |
- |
- |
- |
10-30% |
- |
| Triglycerides in nanoemulsion (wt%) |
0.1-15% |
- |
- |
1-8% |
- |
0.1-15% |
- |
- |
1-8% |
| Soy lecithin identity |
soy lecithin |
- |
- |
- |
PC ≥ 90 wt% |
PC ≥ 90 wt% |
- |
- |
- |
| Preservatives |
at least two; includes propylene glycol, 1-3% |
- |
- |
- |
- |
at least two; includes propylene glycol, 1-3% |
- |
- |
- |
How the claim stack works in practice
- Claims 2 and 7 lock 5-ALA to about 10% w/w. If a gel uses 5-ALA outside “about 10%” but within 3-15%, it still can infringe Claim 1.
- Claims 3 and 8 lock the nanoemulsion content in the gel to 10-30% w/w. If a gel uses nanoemulsion outside that range (even if nanoemulsion chemistry and particle size match), those dependents are not met, but Claim 1 could still be met depending on whether Claim 1 requires a specific gel wt% for nanoemulsion (your Claim 1 text does not state that).
- Claims 4 and 9 lock triglyceride load in the nanoemulsion to 1-8%. A formulation at 0.1-0.9% triglycerides or 8.1-15% would bypass those dependents, but still may fall under Claim 1 if other limits match.
- Claim 5 locks soy lecithin to phosphatidylcholine ≥90 wt%. Products using lecithin with lower phosphatidylcholine content bypass that dependent claim but may still be in range for Claim 1/6 depending on whether those dependents are the only routes.
Claim language features that drive infringement risk
1) “Prior to incorporation” particle size requirement
The claim explicitly sets nanoemulsion particle metrics before mixing into the gel. This narrows the relevant manufacturing measurement point and reduces arguments about particle growth or aggregation after gel formation.
2) Particle size distribution specificity (mean + SD)
The requirement is not only a mean diameter (5-35 nm) but also a size dispersion (standard deviation about 5 nm). This matters for formulation equivalence: a product with droplets in the right mean range but with a substantially different distribution could fall outside.
3) Hard ingredient identity: soy lecithin and polysorbate 80
The surfactant/co-surfactant identity is explicit:
- surfactant: soy lecithin
- co-surfactant: polysorbate 80
Replacing either with a different nonionic or lecithin substitute is the most direct path around.
4) Oil phase specificity: triglycerides
The oil phase must be triglycerides within the stated wt% bands. Substituting other oils (e.g., esters, squalane, medium-chain fatty acids) shifts outside claim boundaries unless they qualify as “triglycerides.”
5) Cosolvent and buffer constraints
- Isopropyl alcohol 1-2% (nanoemulsion wt%)
- Phosphate buffer 5-30 mM
Formulators using ethanol or buffer systems outside that mM range are likely outside the claim.
Practical landscape: where US 11,540,981 fits among 5-ALA topical IP
The claims you provided define a very specific formulation architecture: 5-ALA gel + xanthan gum + preservative system + nm-sized oil-in-water nanoemulsion using lecithin/polysorbate 80/triglycerides with isopropyl alcohol and phosphate buffer.
Within the US 5-ALA topical market, this places the patent into the “advanced delivery system” bucket rather than basic topical gel compositions. The likely competitive effect is on:
- topical 5-ALA gels that use nanoemulsions for penetration
- topical systems that attempt to use lecithin-based surfactant blends with polysorbate 80
- topical 5-ALA products that hit sub-50 nm droplet size targets and specify droplet distribution parameters
Where competitors remain most exposed is in formulations that are close on all of:
- nanoemulsion chemistry (oil phase and surfactant pair)
- droplet size metrics
- gel matrix and preservative logic
Competitive design-around map (claim-targeted divergence points)
The claim set is narrow enough that design-arounds can be identified by “switching” a single major parameter that is explicit in the claim.
Highest-value switches
- Swap polysorbate 80 for a different co-surfactant
- Swap soy lecithin for a different emulsifier or lecithin with phosphatidylcholine below 90 wt% (affects dependent Claim 5 and could affect overall claim coverage depending on which independent claim is asserted)
- Use a non-triglyceride oil phase (or change oil chemistry such that it is not “triglycerides”)
Medium-value switches
- Change isopropyl alcohol level outside 1-2% (nanoemulsion wt%)
- Use phosphate buffer outside 5-30 mM
- Achieve a different droplet size profile (mean outside 5-35 nm and/or SD not “about 5 nm”)
- Alter water window and surfactant load in ways that break the independent claim ranges
Lower-value switches (likely still covered under broader independents)
- Use 5-ALA near 10% (Claim 1 range still covers 3-15%)
- Use xanthan gum in 1-3% range (same)
- Use propylene glycol as a preservative (still may satisfy the required preservative element)
Litigation and enforcement posture (what the claim structure implies)
Even without procedural history, the claim architecture suggests enforceability leverage through multiple overlapping claim layers:
- Claim 1 offers broad numeric coverage for 5-ALA and nanoemulsion composition, with the particle size constraint acting as the main tight technical boundary.
- Claims 2-5 provide layered narrower embodiments that can be used when a product matches the formulation chemistry but differs on numeric preferences (5-ALA concentration, nanoemulsion wt%, triglyceride load, lecithin phosphatidylcholine).
- Claim 6 adds a lecithin compositional qualifier (phosphatidylcholine ≥90 wt%).
- Claim 10 provides a distinct “low triglyceride / low surfactant load” profile that can capture products optimized for stability with minimal oil and surfactant while still meeting nm droplet size.
From an assertion standpoint, this structure allows selection of the best-fitting claim during enforcement, depending on what testing shows for droplet distribution, ingredient chemistry, and the measured nanoemulsion formulation prior to gel mixing.
Key Takeaways
- US 11,540,981 claims a topical 5-ALA·HCl gel built around a nanoemulsion that must be oil-in-water and meet 5-35 nm mean droplet size with standard deviation about 5 nm, measured prior to incorporation into the gel.
- The nanoemulsion must use triglycerides (0.1-15% w/w), soy lecithin and polysorbate 80 (1-30% combined), isopropyl alcohol (1-2%), and phosphate buffer (5-30 mM).
- Claim coverage is strengthened by layered dependents on 5-ALA at about 10%, nanoemulsion gel content 10-30%, triglycerides 1-8%, and soy lecithin phosphatidylcholine ≥90 wt%.
- The cleanest design-arounds target explicit elements: swap the co-surfactant (polysorbate 80), swap soy lecithin, swap triglyceride oil phase, or move the nanoemulsion droplet size distribution outside the stated mean/SD bands.
FAQs
1) Is the particle size requirement for the nanoemulsion in the final gel or before mixing?
It is for the nanoemulsion prior to incorporation into the topical gel composition.
2) Does the claim require both soy lecithin and polysorbate 80?
Yes. The surfactant and co-surfactant identities are explicit.
3) Can a product that uses triglycerides outside 1-8% still infringe?
Yes. The 1-8% limit appears in dependent claim language in your set; Claim 1 allows triglycerides 0.1-15%.
4) What is the most direct technical design-around for a competitor?
Change an explicit nanoemulsion element, especially polysorbate 80 or soy lecithin, or use a non-triglyceride oil phase, or move the droplet size distribution out of 5-35 nm mean with SD about 5 nm.
5) Are the gel components (xanthan gum and propylene glycol) required even if the nanoemulsion matches perfectly?
Yes. The gel matrix and preservative constraints are part of the claimed topical gel composition.
References
[1] US Patent 11,540,981, “Topical gel composition comprising 5-aminolevulinic acid hydrochloride and nanoemulsion.” Claims as provided in the prompt.
