Executive summary: US Drug Patent 11,529,368 claims specific PEG-based colon cleansing compositions/solutions using PEG (MW 2500–4500 Da) at defined dose ranges with alkali/alkaline earth sulphate salts at defined levels, configured for administration in 400–600 mL water and explicitly excluding ascorbate components. Independent claim 1 is directed to a composition with constrained PEG/sulphate amounts and water volume. Independent claim 13 is directed to a solution per liter with the same PEG and sulphate windows, again excluding ascorbate. Dependent claims narrow to preferred PEG masses, preferred sulphate masses, optional electrolytes (NaCl/KCl), and excipients (sucralose, citric acid). Independent claim 19 adds a “consisting essentially of” limitation to a PEG/sulphate solution with controlled optionality and ascorbate exclusion. Method-of-use claims 17–18 cover colon cleansing using the claimed solution, including in combination regimens.
US Patent 11,529,368 scope and claim-by-claim coverage for PEG plus sulphate colon cleansing
What is the invention claimed in US 11,529,368?
The patent is centered on a bowel preparation using:
- Polyethylene glycol (PEG) with average molecular weight 2500 to 4500 Da
- 3.75 to 15 g sulphate salts per claimed composition (or 15–20 g per liter in the solution form)
- 400 to 600 mL water as the ingestion volume window for the composition claims
- Explicit exclusion: the composition/solution is free from ascorbate components
- Optional add-ons: NaCl, KCl, sucralose, citric acid and (for claim 19) optional flavoring agents
Core claim architecture:
- Independent claims for composition (claim 1), solution (claim 13), and “consisting essentially of” solution (claim 19)
- Dependent claims that carve out numerical subsets (PEG mass, PEG fraction, sulphate fraction, electrolyte and excipient ranges)
- Method claims (claims 17–18) that operationalize administration
What do claims 1 and 13 cover: composition vs solution boundaries?
Claim 1: colon cleansing composition (per ingestion batch)
Claim 1 covers a colon cleansing composition comprising:
- PEG 52.5 to 187.5 g with average MW 2500 to 4500 Da
- 3.75 to 15 g of one or more: alkali metal sulphates and/or alkaline earth metal sulphates (or mixtures)
- Configured for colon cleansing in an ingestion volume of 400 to 600 mL water
- Free from ascorbate components
Scope notes (practical claim interpretation):
- The claim is batch-based (PEG and sulphate in g per administered composition) and anchored to a specific ingestion volume window.
- The PEG MW window (2500–4500 Da) is a key chemical boundary. A PEG outside this window (e.g., ~3350 is inside; 4000 is inside; higher/lower average MW is outside) avoids literal coverage.
- The sulphate salt category is broad within its chemistry: any alkali/alkaline earth sulphate combination is eligible, as long as it falls within the defined mass window.
- The “free from ascorbate components” term is a categorical exclusion. Even trace ascorbate could become relevant in infringement analysis depending on detection limits and the patent’s intended meaning in prosecution, but the claim language is a hard exclusion category.
Claim 13: colon cleansing solution (per liter basis)
Claim 13 covers a colon cleansing solution comprising:
- 130 to 250 g PEG per liter with average MW 2500 to 4500 Da
- 15 to 20 g per liter sulphate salt(s) (alkali/alkaline earth sulphates or mixtures)
- 400 to 600 mL water
- Free from ascorbate components
Scope notes:
- This is a concentration-based claim. Coverage hinges on meeting the PEG and sulphate per liter ranges and the PEG MW window.
- The inclusion of “400 to 600 ml water” in the solution claim is an additional constraint tying concentration to a particular water volume regime.
- A product formulation that is batch-matched to claim 1 may or may not meet the per-liter concentration thresholds in claim 13, depending on how the label instructions relate to final mixing volume.
What PEG molecular weight and dosing windows drive infringement risk?
PEG MW window (common to independent claims)
Both claim 1 and claim 13 require:
- PEG average molecular weight: 2500 to 4500 Da
Implications:
- If a generic or alternative prep uses PEG with a different average MW (often found in PEG 3350 as a common bowel prep component), it may still fall in-range. The risk turns on exact “average molecular weight” of the PEG grade used.
PEG mass windows: batch claim vs concentration claim
Claim 1 PEG range: 52.5 to 187.5 g
Claim 13 PEG range: 130 to 250 g per liter
Dependent claims refine preferred sub-ranges:
- Claim 3: 75 to 150 g PEG
- Claim 4: 90 to 112.5 g PEG
- Claim 5: 100 g PEG
These dependent claims create a ladder of narrower infringement hooks.
What sulphate salt categories and mass windows are claimed?
Sulphate salt type
Both independent claims cover:
- alkali metal sulphates and/or alkaline earth metal sulphates; mixtures allowed
This category typically includes salts such as sodium sulphate (alkali) and magnesium sulphate or calcium sulphate (alkaline earth), depending on the specific formulation.
Sulphate mass windows
Claim 1 sulphate window: 3.75 to 15 g per composition batch
Claim 13 sulphate window: 15 to 20 g per liter
Dependent claim 11 gives a specific embodiment:
- PEG 100 g
- PEG MW 3000 to 4000 Da
- sulphate component 9 g sodium sulphate (explicitly sodium sulphate)
Dependent claim 12 recasts ranges as composition proportions:
- PEG at 77.8% to 98.0% w/w
- sulphate component at 2.0% to 22.2% w/w
What other excipients are explicitly claimed or narrowed (NaCl, KCl, sucralose, citric acid)?
Electrolytes (NaCl and KCl)
Claim 8 (composition):
- 0.75 to 2.25 g sodium chloride
- 0.075 to 2.25 g potassium chloride
Claim 11 ties a fully specified electrolyte package:
- PEG 100 g; PEG MW 3000–4000 Da
- sulphate: 9 g sodium sulphate
- sodium chloride 1.5 to 2.25 g
- potassium chloride 0.15 to 1.5 g
- plus sucralose and citric acid
Claim 14 (solution):
- 1.0 to 4.0 g per liter NaCl
- 0.1 to 3.0 g per liter KCl
Scope notes:
- These dependent claims add optionality. A competitor omitting NaCl/KCl may still infringe independent claims 1/13/19 if it hits PEG/sulphate/water volume and ascorbate exclusion.
- A competitor including electrolytes must ensure the quantities do not land inside dependent-claim numerical windows unless they accept risk that a narrower claim could be asserted.
Sweetener: sucralose
Claim 9: sweetener wherein sweetener is sucralose
Claim 15 (solution): sucralose
Claim 11 also includes sucralose as part of a specific embodiment.
Acid: citric acid
Claim 10: further comprising citric acid
Claim 16 (solution): citric acid
Claim 11 also includes citric acid.
What does the “free from ascorbate components” limitation do to the claim perimeter?
All independent claims (1, 13, 19) require:
- composition/solution free from ascorbate components
Functional role:
- This is a binary chemical exclusion that can create:
- A design-around path by removing ascorbate-related materials
- A litigation focus on whether an accused product uses any ascorbate component, even if at low levels, depending on how “free from” is treated during claim construction and evidence evaluation.
Does claim 19 expand or narrow the “constisting essentially of” scope?
Claim 19: colon cleansing solution “consisting essentially of”
Claim 19 covers a solution:
- 130 to 250 g PEG per liter, MW 2500–4500 Da
- 15 to 20 g per liter sulphate salt(s)
- 400–600 mL water
- Optionally 0.5 to 5.0 g per liter NaCl
- Optionally 0.1 to 3.0 g per liter KCl
- Optionally one or more flavoring agents
- Optionally one or more sweeteners
- Free from ascorbate components
- “consisting essentially of” language limits inclusion of additional ingredients beyond what does not materially affect the basic and novel characteristics.
Scope notes:
- Compared with claim 13 (which does not use “consisting essentially of”), claim 19 can be both:
- Broader in excluding strict necessity of NaCl/KCl/other optional ingredients, because they are “optional”
- Narrower in that it constrains what other ingredients can be present without violating the “consisting essentially of” boundary
- The most important infringement lever remains the requirement to be ascarbate-free and to stay inside PEG and sulphate mass and MW windows.
What do the method claims add: administration and combination regimens?
Claim 17: method of cleansing using the claimed solution
Claim 17 covers:
- administering the solution of claim 13 to cleanse a colon
This is a direct product-based method claim. If an accused product meets the claim 13 solution composition, use to cleanse a colon fits the method claim.
Claim 18: combination dosing
Claim 18 covers:
- administering claim 13 solution in combination with a different colon cleansing solution
This claim targets multi-agent regimens. It is not clear from the text what “different colon cleansing solution” means, but the claim’s inclusion creates additional infringement hooks for combination prescriptions and protocols.
Patent landscape implications for freedom-to-operate (FTO) around US 11,529,368
What claim numbers most matter for launching generic/alternative preps?
- Independent product claims: 1, 13, 19
- Dependent narrower embodiments: 3–6 (PEG subranges), 6–7 (sulphate masses), 8 (NaCl/KCl ranges), 9–10 (sucralose and citric acid), 11 (fully specified embodiment), 12 (w/w ranges), 14–16 (solution electrolytes/sweeteners/acid)
- Method claims: 17–18 (administration/combinations)
In practice, a challenger typically needs to assess:
- Whether its PEG grade sits inside 2500–4500 Da
- Whether batch/concentration instructions match PEG and sulphate windows
- Whether the product is truly ascorbate-free
- Whether included sweeteners/acid/electrolytes trigger dependent-claim assertions
Design-around levers present in the claim text
- Use PEG with average molecular weight outside 2500–4500 Da
- Move PEG and/or sulphate masses so that the composition no longer fits 52.5–187.5 g PEG and 3.75–15 g sulphate for the 400–600 mL ingestion volume, or so it fails the per-liter windows in claim 13/19
- Introduce or retain ascorbate components would violate the “free from ascorbate components” language and typically is not a design-around strategy
- Adjust water volume such that the ingestion volume is outside 400–600 mL for claim 1, though this can be difficult if label instructions are fixed
Claim scope mapping table (what must be present for infringement)
| Claim |
Entity type |
PEG requirement |
Sulphate requirement |
Water/volume requirement |
Ascorbate-free? |
Optional excipients claimed |
| 1 |
Composition |
52.5–187.5 g PEG, MW 2500–4500 Da |
3.75–15 g alkali/alkaline earth sulphate(s) |
Configured for colon cleansing in 400–600 mL water |
Yes |
NaCl/KCl (dep.), sucralose (dep.), citric acid (dep.) |
| 3/4/5 |
Composition (dep.) |
75–150 g; or 90–112.5 g; or 100 g |
(within claim 1) |
400–600 mL |
Yes |
Same as claim 1 baseline |
| 6/7 |
Composition (dep.) |
(within claim 1) |
6–15 g; or 9 g |
400–600 mL |
Yes |
same |
| 8 |
Composition (dep.) |
(within claim 1) |
(within claim 1) |
400–600 mL |
Yes |
NaCl 0.75–2.25 g; KCl 0.075–2.25 g |
| 9/10 |
Composition (dep.) |
(within claim 1) |
(within claim 1) |
400–600 mL |
Yes |
sucralose; citric acid |
| 11 |
Composition (dep.) |
100 g; MW 3000–4000 Da |
9 g sodium sulphate |
400–600 mL |
Yes |
NaCl 1.5–2.25 g; KCl 0.15–1.5 g; sucralose; citric acid |
| 12 |
Composition (dep.) |
PEG 77.8–98.0% w/w |
sulphate 2.0–22.2% w/w |
(implied by claim 1) |
Yes |
— |
| 13 |
Solution |
130–250 g/L PEG, MW 2500–4500 Da |
15–20 g/L sulphate(s) |
400–600 mL water |
Yes |
NaCl/KCl, sucralose, citric acid (dep.) |
| 14 |
Solution (dep.) |
(within claim 13) |
(within claim 13) |
400–600 mL |
Yes |
NaCl 1.0–4.0 g/L; KCl 0.1–3.0 g/L |
| 15/16 |
Solution (dep.) |
(within claim 13) |
(within claim 13) |
400–600 mL |
Yes |
sucralose; citric acid |
| 17 |
Method |
administers solution of claim 13 |
N/A |
N/A |
Yes (via claim 13) |
colon cleansing use |
| 18 |
Method |
administers claim 13 + different colon cleansing solution |
N/A |
N/A |
Yes (via claim 13) |
combination regimen |
| 19 |
Solution |
130–250 g/L PEG, MW 2500–4500 Da |
15–20 g/L sulphate(s) |
400–600 mL water |
Yes |
optional: NaCl, KCl, flavoring, sweeteners; “consisting essentially of” |
Litigation and Orange Book risk: not computable from provided information
No information is provided here about:
- Orange Book listings tied to US 11,529,368
- FDA reference product(s) and NDA/BLA numbers
- whether the patent is listed for specific dosage forms
- Paragraph IV or 505(b)(2) challenge history
- settlement agreements or court decisions
Without those, no complete and accurate landscape timeline across FDA and generic challengers can be produced from the claims text alone.
Key Takeaways
- US 11,529,368 is built around a PEG (MW 2500–4500 Da) plus alkali/alkaline earth sulphate bowel prep with 400–600 mL water constraints and a hard exclusion of ascorbate components.
- Independent claims 1 (batch composition), 13 (solution per liter), and 19 (“consisting essentially of” solution) define the core perimeter. Dependent claims narrow to specific PEG masses, PEG MW windows, sulphate masses, and add-on NaCl/KCl, sucralose, and citric acid.
- Method claims 17–18 extend the patent to use of the claim 13 solution for colon cleansing, including combination regimens.
- The highest-value infringement determinants are the PEG molecular weight, the PEG and sulphate quantitative windows, and ascorbate-free status.
FAQs
1) How does “ingestion volume of 400 to 600 ml water” limit claim 1?
It anchors infringement to the claimed regimen’s mixing/administration instruction such that the colon cleansing composition is configured for use in that water volume window.
2) Can a formulation outside the PEG MW 2500–4500 Da window avoid all independent claims?
Yes, if it falls outside the claimed PEG average molecular weight ranges, it does not meet the independent-claim PEG element in claims 1/13/19.
3) What is the practical effect of including sucralose and citric acid?
Including either can trigger dependent-claim assertions (claims 9–11 and 10, 15–16, and 11), even if the product may still meet independent claim elements.
4) What is the role of “consisting essentially of” in claim 19?
It permits optional ingredients (flavoring, sweeteners, electrolytes within optional ranges) while restricting additional ingredients that could materially affect the basic and novel characteristics.
5) Do the method claims require a specific clinical indication wording?
No. Claim 17 and 18 require administration to cleanse a colon, with claim 18 requiring combination with another colon cleansing solution.
References
- US Patent 11,529,368 claims 1–19 (provided claim text).
