Scope and Claims Analysis for US Patent 11,752,129 (Apremilast Oral Dosage Form with Solid Dispersion, Swellable Layer, and Drug-Release Orifice)
US Patent 11,752,129 claims an oral, once-daily apremilast tablet architecture with a two-part core (a drug layer with apremilast + HPMCAS solid dispersion and a swellable layer), plus a specific coating layer and a drug-release orifice on the tablet surface. The protection is tightly framed by quantitative ranges for excipients, polymer molecular weights, and the presence of a release-orifice feature. Method claims add fed-state, once-daily PDE4-inhibition dosing for specified indications including psoriasis and psoriatic arthritis.
What is US Patent 11,752,129 protecting: apremilast formulation and release-orifice tablets?
Short answer: The patent protects specific oral apremilast tablet formulations with (1) solid dispersion of apremilast in HPMCAS, (2) defined polymer/excipient ratios in a drug layer and a swellable layer, (3) a coating containing cellulose acetate + polyethylene glycol, and (4) a tablet surface having at least one drug release orifice. It also protects once-daily administration under fed conditions for PDE4-mediated diseases such as psoriasis.
Claim 1 scope (independent formulation claim)
Claim 1 is the broad anchor for the tablet composition. It requires all of the following:
A. Oral dosage form elements
- A core tablet with:
- Drug layer containing:
- 8–11 wt% apremilast
- 8–11 wt% HPMCAS (hypromellose acetate succinate)
- 2–7 wt% mannitol
- 40–45 wt% polyethylene oxide (PEO), 200,000 Da
- 0.1–0.5 wt% magnesium stearate
- 0.1–0.5 wt% colloidal silicon dioxide
- where apremilast and HPMCAS are in a solid dispersion
- Swellable layer containing:
- 18–25 wt% PEO, 5,000,000 Da
- 7–10 wt% microcrystalline cellulose
- 1.5–3.5 wt% sodium chloride
- 0.01–0.2 wt% iron oxide
- 0.05–0.3 wt% magnesium stearate
- A coating layer on the core tablet comprising:
- cellulose acetate + polyethylene glycol
- The oral dosage form surface comprises at least one drug release orifice
B. Technical enforceability implication
The “solid dispersion” requirement and the release-orifice requirement are non-trivial constraints. They narrow the patent to products that can plausibly be engineered to avoid one or both elements (for example by using a different dispersion matrix than HPMCAS, using a different dissolution architecture without an orifice, or using different polymer molecular weights and distributions).
Claim 5 scope (alternative formulation family with different excipient set)
Claim 5 is also independent and is the broader “variant” family. It requires:
- Drug layer:
- 9–15 wt% apremilast
- 10–15 wt% HPMCAS
- 0–27 wt% mannitol
- 30–40 wt% PEO, 200,000–300,000 Da (or mixture)
- 2–8 wt% sodium chloride
- 0.1–0.5 wt% magnesium stearate
- 0.1–0.5 wt% colloidal silicon dioxide
- apremilast + HPMCAS in solid dispersion
- Swellable layer:
- 15–25 wt% PEO, 5,000,000 Da
- 5–10 wt% microcrystalline cellulose
- 2–4 wt% sodium chloride
- 0.01–0.1 wt% iron oxide
- 0.05–0.3 wt% magnesium stearate
- Coating layer:
- cellulose acetate + polyethylene glycol
- Surface includes at least one drug release orifice
Key structural difference vs claim 1: Claim 5 shifts sodium chloride into the drug layer and expands PEO molecular weight for the drug layer to 200,000–300,000 Da (mixture allowed). It also relaxes mannitol to 0–27 wt%.
How do the dependent claims narrow the formulation (weight-specific exemplars)?
Claims 2–4 and 6–13 supply specific quantitative embodiments. These dependent claims function as:
- fallback positions if a defendant argument targets the ranges in claims 1/5, and
- practical markers for “design-around” boundaries (if an accused product matches an exemplar composition, infringement risk increases).
Claim set 1 exemplars (claims 2–4)
All incorporate:
- apremilast + HPMCAS solid dispersion
- drug layer PEO at 200,000 Da
- swellable layer PEO at 5,000,000 Da
- coating includes cellulose acetate + PEG
- at least one drug release orifice
| Claim |
Drug layer: apremilast / HPMCAS |
Drug layer PEO (200k) |
Drug layer mannitol |
Swellable layer PEO (5M) |
Swellable layer NaCl |
Iron oxide |
Mg stearate |
| 2 |
75 mg / 75 mg |
314.8 mg |
22.1 mg |
159.6 mg |
21.1 mg |
0.5 mg |
Drug 2.4 mg; Swellable 1.2 mg |
| 3 |
55 mg / 55 mg |
230.9 mg |
16.2 mg |
117 mg |
15.5 mg |
0.4 mg |
Drug 1.7 mg; Swellable 0.9 mg |
| 4 |
27.5 mg / 27.5 mg |
115.6 mg |
8.1 mg |
58.6 mg |
7.8 mg |
0.2 mg |
Drug 1.0 mg; Swellable 0.5 mg |
Claim set 5 exemplars (claims 6–13)
All incorporate:
- apremilast + HPMCAS solid dispersion
- drug layer PEO is 200k–300k or specific 300k
- swellable layer PEO at 5M
- coating includes cellulose acetate + PEG
- at least one drug release orifice
- sodium chloride present in both drug layer and swellable layer, with different ranges per claim
| Claim |
Apremilast / HPMCAS (mg) |
Drug layer PEO MW |
Drug layer NaCl (mg) |
Drug layer mannitol |
Swellable layer NaCl (mg) |
Iron oxide (mg) |
| 6 |
100 / 100 |
200k–300k |
26.7 |
0 (not listed) |
22.9 |
0.5 |
| 7 |
100 / 100 |
300k |
53.3 |
0 (not listed) |
22.9 |
0.5 |
| 8 |
75 / 75 |
200k–300k |
20.0 |
0 (not listed) |
17.2 |
0.4 |
| 9 |
75 / 75 |
300k |
40.0 |
0 (not listed) |
17.2 |
0.4 |
| 10 |
55 / 55 |
200k–300k |
14.7 |
0 (not listed) |
12.6 |
0.3 |
| 11 |
55 / 55 |
300k |
29.3 |
0 (not listed) |
12.6 |
0.3 |
| 12 |
27.5 / 27.5 |
200k–300k |
7.3 |
0 (not listed) |
6.3 |
0.1 |
| 13 |
27.5 / 27.5 |
300k |
14.7 |
0 (not listed) |
6.3 |
0.1 |
Interpretation for claim strategy: The exemplars in claims 6–13 appear to emphasize sodium chloride levels that track within the claim 5 ranges, and they lock the swellable layer iron oxide to 0.1–0.5 mg (per embodiment). A challenger aiming to avoid infringement would focus on:
- elimination or modification of the orifice feature;
- changing HPMCAS role (solid dispersion requirement);
- changing PEO molecular weight distribution in the drug layer (200k vs 300k vs mixture); and/or
- altering NaCl placement and level such that it fails the claim 1 or claim 5 ranges simultaneously.
What method-of-use claims protect (fed-state once-daily PDE4 inhibition)?
Claims 14–17 are method claims tied to dosing conditions and indications.
Claim 14 and 16: once daily under fed conditions
- Claim 14: administering the oral dosage form of claim 1 once daily under fed conditions to treat a disease/disorder ameliorated by inhibiting PDE4.
- Claim 16: same concept but the dosage form is that of claim 5.
These claims tie formulation to a regimen: a product that is arguably the same composition but used outside fed-state dosing or outside once-daily timing may create a non-infringement argument on the induced infringement theory.
Claims 15 and 17: specified diseases
- Claim 15: psoriasis, psoriatic arthritis, or Behcet’s disease.
- Claim 17: same list.
Induced infringement exposure
In US practice, the most realistic infringement theories for method-of-use claims typically depend on:
- FDA labeling (indication + dosing instructions),
- physician prescribing patterns,
- and evidence of direction or encouragement for “fed conditions” use.
This claim set is therefore sensitive to the label’s dosing language.
How does the “drug release orifice” limitation change infringement risk?
The claims require “at least one drug release orifice” on the oral dosage form surface. That is likely the most engineerable feature in the claim set.
From a landscape perspective, orifice-based limitations create:
- a clear infringement discriminator for product morphology;
- evidence leverage through tablet cross-sections and imaging;
- potential design-arounds by altering manufacturing to eliminate discrete orifice structures while retaining other polymer layering features.
If the accused product uses a different release mechanism (diffusion, erosion, osmotic pumping, or coated-layer porosity not forming a discrete orifice), infringement analysis would turn on claim construction of “orifice” and whether the accused feature is structurally and functionally equivalent under the prevailing doctrine.
What patent landscape concerns exist around apremilast oral formulations?
Key landscape theme: US Patent 11,752,129 is not a single-ingredient claim. It is a tableting architecture patent combining:
- HPMCAS solid dispersion (apremilast),
- PEO-based matrix design with different molecular weights (200k/300k in drug layer; 5M in swellable layer),
- defined excipient placement (mannitol vs NaCl roles),
- film-coat composition (cellulose acetate + PEG),
- and a tablet-surface orifice.
This combination increases the chance that other patents in the apremilast space address:
- different solid dispersion carriers (other than HPMCAS),
- other polymer grades or ratios,
- different tablet geometry or orifice architecture,
- alternative coating compositions,
- and dosing regimen claims.
In an enforcement context, companies generally face a layered challenge where a competitor can attempt to “slice” around one limitation but must clear the remaining constraints.
How strong is the patent estate for competitors seeking generic or authorized alternatives?
Strength drivers in this specific patent:
- Quantitative excipient ranges reduce functional ambiguity.
- Molecular weight specificity for PEO creates a hard formulation discriminator.
- Solid dispersion requirement narrows the mechanism for dispersion of apremilast.
- Orifice limitation provides a strong physical-structure hook.
- Fed-state, once-daily regimen adds a second axis for method claims.
Potential weakness drivers:
- If the claim construction of “orifice” is narrow (requiring a distinct, manufacturable opening), some alternative release designs may avoid literal infringement.
- If prior art exists for layered apremilast tablets with similar polymers, obviousness risk rises. The risk materializes only if the prior art discloses all constraints or if there is a strong motivation to combine within the claimed ranges.
What does this mean for generic entry risk scenarios?
For a prospective generic or lifecycle competitor, risk under US Patent 11,752,129 would center on whether the product is:
- compositionally within claim 1 or claim 5 ranges and uses HPMCAS solid dispersion; and
- structurally includes a drug release orifice on the tablet surface; and
- used once daily under fed conditions for a protected indication for the method claims.
Low-risk design-around levers (practical):
- remove the discrete orifice feature (or replace it with a different release architecture that does not satisfy “orifice”);
- replace HPMCAS solid dispersion with a different dispersion system (still may face other patents);
- switch PEO grades or molecular weight distribution outside the claim windows;
- alter NaCl placement so the drug layer and swellable layer do not meet the required ranges simultaneously.
High-risk scenario: an “authorized generic” or “follow-on” product that keeps the same layered matrix and orifice feature while matching HPMCAS-PEO formulation and fed-state once-daily dosing.
Litigation and regulatory status: what is the Orange Book status of US 11,752,129?
No Orange Book listing, Patent Listing Code, FDA approval mapping, or expiration timeline can be provided from the information supplied here. Without the application-to-drug linkage, assignment, filing dates, and FDA listing identifiers, a full regulatory exclusivity and Orange Book status analysis cannot be generated.
Key takeaway tables for fast infringement mapping
Claim limitation checklist (literal infringement map)
| Claim element |
Claim 1 |
Claim 5 |
What to compare in an accused product |
| Core tablet with two layers |
Yes |
Yes |
Presence of distinct drug layer + swellable layer |
| Drug layer apremilast |
8–11 wt% |
9–15 wt% |
Apremilast loading |
| HPMCAS solid dispersion |
Required |
Required |
Evidence of HPMCAS dispersion state |
| Drug layer PEO grade |
40–45 wt% (200k Da) |
30–40 wt% (200k–300k) |
PEO MW and grade distribution |
| Mannitol |
2–7 wt% |
0–27 wt% |
Mannitol content and role |
| Sodium chloride placement |
Swellable layer only |
Both drug layer and swellable |
NaCl distribution between layers |
| Swellable layer PEO |
18–25 wt% (5M Da) |
15–25 wt% (5M Da) |
5M PEO grade |
| Iron oxide |
0.01–0.2 wt% |
0.01–0.1 wt% |
Iron content |
| Coating composition |
Cellulose acetate + PEG |
Same |
Coat composition |
| Surface feature |
At least one drug release orifice |
Same |
Tablet-morphology/orifice presence |
Method claim trigger checklist
| Method claim element |
Requirement |
| Dosage form |
Claim 1 or claim 5 formulation |
| Dosing frequency |
Once daily |
| Food condition |
Under fed conditions |
| Indication / disease |
PDE4-ameliorated; specified: psoriasis, psoriatic arthritis, Behcet’s disease |
Key Takeaways
- US Patent 11,752,129 protects a layered apremilast tablet with HPMCAS solid dispersion, PEO molecular-weight-specific matrices (200k/300k drug layer, 5M swellable layer), a cellulose acetate + PEG coating, and a tablet surface drug release orifice.
- Claim 1 is anchored to a drug layer with mannitol (2–7 wt%) and drug-layer PEO at 200k Da, while claim 5 shifts to broader sodium chloride placement (including drug layer) and allows 0–27 wt% mannitol and PEO 200k–300k.
- Dependent claims 2–4 and 6–13 provide multiple weight-specific embodiments that function as strong fallback infringement targets.
- Method claims 14–17 add fed-state, once-daily dosing and specify indications including psoriasis and psoriatic arthritis (and Behcet’s disease).
- The release-orifice feature and the HPMCAS solid dispersion requirement are the most direct formulation/disciplined morphological points for design-around and evidence gathering.
FAQs
1. What does “apremilast and HPMCAS are in a solid dispersion” require for infringement analysis?
It requires the apremilast to be dispersed in HPMCAS in a manner consistent with solid dispersion formation, not merely physical mixing. For infringement, the accused product’s dispersion state would be compared to claim construction and evidentiary characterization.
2. Can a product avoid infringement by changing PEO molecular weight from 200,000 Da to 300,000 Da?
Not if it still falls within the specific claim ranges. Claim 1 is limited to 200,000 Da, while claim 5 permits 200,000–300,000 Da (mixture allowed). Changing to 300,000 Da may still fall under claim 5.
3. What is the significance of placing sodium chloride in the drug layer under claim 5?
Under claim 1 sodium chloride is specified in the swellable layer (1.5–3.5 wt%), while claim 5 requires sodium chloride in both the drug layer (2–8 wt%) and swellable layer (2–4 wt%). If the accused product moves NaCl placement or level outside these windows, it may avoid one claim family but still face the other.
4. How do “fed conditions” once-daily method claims typically get enforced?
They track labeled dosing instructions and prescribing practices that involve ingestion with food. If the accused product’s marketed use does not match “once daily under fed conditions” for the claimed indication, method exposure can diminish.
5. Does removing the “drug release orifice” eliminate risk entirely?
It directly targets a required limitation in both formulation independent claims (1 and 5). If the tablet surface does not contain at least one qualifying drug release orifice, literal infringement on those claims becomes harder, though other patents in the apremilast tablet space may still apply.
References (APA)
- US Patent No. 11,752,129. (n.d.). United States Patent and Trademark Office.
