Scope and Claims: US Drug Patent 12,370,136 (Atorvastatin Aqueous Oral Suspension)
US Drug Patent 12,370,136 claims an aqueous suspension for oral administration of atorvastatin with tightly defined particle size, specific suspension system, and an explicit exclusion of solubilizer and stabilizer. The claim set is built around a core composition and then multiple narrower embodiments specifying ranges and excipient selections (preservatives, co-solvents, sweeteners, flavoring, and pH).
What the independent claim covers (Claim 1)
Claim 1 defines a suspension with these required elements:
| Claim 1 element |
Required limitation |
Numeric boundaries / selections |
| Dosage form |
Aqueous suspension for oral administration |
Oral suspension in water vehicle |
| Active |
Atorvastatin |
About 4 mg/mL |
| Suspending agent system |
Must be in about 2% w/w |
Split: carboxymethyl cellulose sodium (CMC-Na) ~0.7% w/w and magnesium aluminum silicate ~1.3% w/w |
| Excipients |
One or more pharmaceutically acceptable excipients selected from co-solvent, preservative, sweetener, buffer, flavoring |
Must be “selected from” the listed categories |
| Particle size |
Atorvastatin has d90 particle size |
1 µm to 15 µm |
| Exclusion |
Suspension does not contain a solubilizer and a stabilizer |
Absolute negative limitation |
| Vehicle |
Water |
Water-based |
Hard scope takeaways
- The suspension vehicle is water, with atorvastatin at ~4 mg/mL.
- The suspension’s rheology/dispersion system is not generic: it is a two-component suspending package with specified proportions.
- The quality attribute is particle size: d90 1-15 µm.
- The formulation is constrained by a negative formulation feature: no solubilizer and no stabilizer.
How dependent claims narrow the field (Claims 2–13)
The dependent claims tighten scope in five main ways: fixed active concentration, preservative identity and level, co-solvent identity, sweetener identity and level, flavoring level, and pH range.
Active strength
- Claim 2: Atorvastatin present in an amount of 4 mg/mL (tightens “about 4 mg/mL” to a specific value).
Preservatives
Claims 3, 5, 6, 7, 8 specify preservative parameters.
- Claim 3: Preservative present at 0.01% w/w to 0.5% w/w.
- Claim 5: Preservative selected from: benzyl alcohol, chlorobutol, chlorocresol, alkyl ester of paraben, phenol, phenyl ethanol, sodium benzoate, or a combination.
- Claim 6: Expands preservative selection to include: the Claim 5 list plus propylene glycol, chloroform; and fixes a consistent preservative amount range 0.01% to about 0.5% w/w.
- Claim 7: Preservative comprises an alkyl ester of paraben.
- Claim 8: Paraben alkyl ester at 0.01% to about 0.5% w/w.
Scope implications of the preservative block
- A competitor can fall outside Claim 1 equivalents by changing preservative selection or moving preservative outside the covered amounts.
- However, Claim 1 already only requires “one or more excipients” from the listed categories; dependent claims are what tie those excipients to specific chemistries and levels. The independent claim is broader on excipient selection, narrower on the suspending system, particle size, and solubilizer/stabilizer exclusion.
Co-solvents
- Claim 4: Co-solvent is selected from: alcohol, glycerin, polyhydric alcohol, propylene glycol, or combinations.
Note that propylene glycol appears in both the co-solvent list and preservative expansions (Claim 6).
Sweeteners
- Claim 9: Sweetener selected from: sucrose, glucose, glycerin, sorbitol, saccharin sodium, sucralose, aspartame, acesulfame potassium, or combinations.
- Claim 10: Sweetener amount 0.1% w/w to 2% w/w.
Flavoring agent
- Claim 11: Flavoring agent present at 0.01% to 2.0% w/w.
pH (buffering context)
- Claim 12: pH 5 to 10.
- Claim 13: pH 6 to 9.
These pH claims apply to the suspension’s overall pH, whether achieved via buffers or via excipient selection alone.
Claim Construction Lens: What is likely “scope-determinative” for infringement
The strongest enforceable anchors are those that are both central to the composition and precisely defined:
1) Suspensions agent system is fixed in composition ratio and total level
Claim 1 requires:
- Suspending agent amount: about 2% w/w
- CMC-Na: about 0.7% w/w
- Magnesium aluminum silicate: about 1.3% w/w
This is not a “comprising” generic suspension system; it is a mandatory quantitative recipe for the suspending agent package.
2) Particle size is bounded by d90, not only by qualitative “micronized” descriptors
Claim 1 requires:
If a formulation has a d90 outside that range, it does not meet Claim 1’s particle-size limitation.
3) The solubilizer and stabilizer exclusion is absolute
Claim 1 states the suspension does not contain a solubilizer and a stabilizer.
This negative limitation is typically high-leverage in both:
- Design-around: exclude or avoid anything that qualifies as a solubilizer or stabilizer.
- Litigation: argue about whether particular excipients are “solubilizer” or “stabilizer” within the claim’s meaning.
4) Active strength and vehicle are required
Claim 1 includes:
- Atorvastatin about 4 mg/mL
- Vehicle comprising water
This combination is also “design-around capable” by moving concentration or using non-aqueous vehicles, but it may be difficult if the product must be water-based for practical dosing and stability.
What this patent does and does not cover (practical coverage map)
In-scope product profile (meets Claim 1)
A product likely falls in-scope if it has all of the following simultaneously:
- Water-based oral suspension
- Atorvastatin around 4 mg/mL
- Total suspending agent ~2% w/w made from:
- CMC-Na ~0.7% w/w
- Magnesium aluminum silicate ~1.3% w/w
- d90 particle size between 1 and 15 µm
- No solubilizer and no stabilizer
- Optional excipients from the listed categories (co-solvent/preservative/sweetener/buffer/flavor), plus pH in covered ranges if asserted by dependent claims
Likely out-of-scope vectors (typical design-around levers)
A competitor can be pushed outside Claim 1 by changing at least one scope-determinative element:
- Switch the suspending system away from the specified CMC-Na + magnesium aluminum silicate proportions
- Move d90 outside 1–15 µm
- Change formulation to include a solubilizer or stabilizer (or use an excipient argued to qualify as such)
- Adjust atorvastatin concentration away from about 4 mg/mL
- Use a vehicle that is not “comprising water” as a core component (depending on claim interpretation of “comprising”)
Dependent-claim “bands” that create narrower infringement windows
Dependent claims define sub-classes that are important when assessing a specific candidate product.
Preservative sub-bands
- Presence and concentration: 0.01–0.5% w/w
- Chemical identity: benzyl alcohol, chlorobutol, chlorocresol, alkyl paraben ester, phenol, phenyl ethanol, sodium benzoate (and in Claim 6: plus propylene glycol and chloroform)
- Narrowest carve: paraben alkyl ester between 0.01% and 0.5%
Co-solvent sub-band
- Co-solvent choice set: alcohol, glycerin, polyhydric alcohol, propylene glycol (or combinations)
Sweetener sub-bands
- Identity set plus concentration band: 0.1–2% w/w
Flavoring band
pH bands
- 5–10 (broad)
- 6–9 (narrow)
Patent landscape: what can be inferred from the claim architecture
This analysis is limited to what is contained in the claim language you provided. No bibliographic event data, citing patents, prosecution history, assignee, filing date, priority claims, or expiry information is included in your prompt; without those, a complete landscape map (family scope, continuations, and real-time status) cannot be produced.
That said, the landscape risk profile can be inferred from the structure of Claim 1 and its dependent fallbacks:
Likely competitive “hot zones”
- Atorvastatin oral suspensions that use CMC-Na + magnesium aluminum silicate at the specified ratio and target micronized/dispersed particle size distribution.
- Formulations attempting to avoid solubilizers and stabilizers but still hitting workable suspendability and shelf-life.
Likely contention points
- Definition boundary for “solubilizer” and “stabilizer” relative to particular excipients (especially polyols, buffering agents, preservatives with dual functions, and any crystallization-control agents).
- d90 measurement methodology: whether the tested particle size distribution matches the claimed d90 band, and what dispersion/handling state is used before measurement.
Key Takeaways
- US 12,370,136 claims a water-based oral suspension of atorvastatin ~4 mg/mL with a fixed suspending system: CMC-Na ~0.7% w/w + magnesium aluminum silicate ~1.3% w/w (total suspending agent ~2% w/w).
- The core quality attribute is atorvastatin d90 particle size 1–15 µm.
- The formulation has a hard negative limitation: it does not contain a solubilizer and a stabilizer.
- Dependent claims narrow the formulation by specifying preservative identity and amount, co-solvent identity, sweetener identity and amount, flavoring amount, and pH range (5–10 or 6–9).
- Landscape relevance concentrates on formulation candidates that match the recipe + particle size + negative solubilizer/stabilizer constraint. Minor excipient changes outside dependent claim parameters may not avoid Claim 1 if the scope-determinative elements remain unchanged.
FAQs
1) What is the central claim limitation that most strongly constrains formulation design?
The suspending agent composition and proportions (CMC-Na ~0.7% w/w and magnesium aluminum silicate ~1.3% w/w within ~2% w/w total) plus d90 particle size 1–15 µm.
2) Can a formulation with a different preservative still infringe?
It can, as long as the formulation meets Claim 1. The preservative selections and concentration ranges in Claims 3–8 primarily narrow dependent embodiments rather than replacing the Claim 1 anchors.
3) How does the “does not contain a solubilizer and a stabilizer” language affect infringement risk?
It creates a binary constraint: if the accused formulation contains an excipient argued to qualify as a solubilizer or stabilizer, it can fail the claim. Conversely, if it truly contains none that qualify, it stays closer to the asserted scope.
4) What property drives particle-size compliance?
d90 of atorvastatin must be 1 µm to 15 µm; formulations must hit that distribution rather than relying on general micronization claims.
5) Which dependent claims provide the most specific “work backwards” target profile?
Claims covering preservatives (3, 5–8), sweetener (9–10), flavoring (11), and pH (12–13) provide the most explicit formulation bands beyond Claim 1’s core composition and exclusion.
References (APA)
[1] United States Patent 12,370,136, claims 1–13 (provided claim text).
