United States Patent 7,175,855: Scope, Claims, and Patent Landscape for Ziprasidone HCl Oral Formulations
What is US 7,175,855 claiming, in plain formulation terms?
US 7,175,855 claims an oral pharmaceutical composition containing ziprasidone hydrochloride in water, with a defined set of excipients and concentration bands intended to control physical stability and taste/organoleptic performance.
Claim 1: Core composition (ziprasidone + water + three excipient classes)
Claim 1 requires, in one composition:
- Ziprasidone hydrochloride
- Water
- Polysorbate 80: 0.05 to 0.3 wt%
- Xanthan gum: 0.01 to 10 wt%
- Colloidal silicon dioxide: 0.05 to 2.0 wt%
Claim 2: Adds a taste masking salt band
Claim 2 limits Claim 1 further by adding:
- 0.5 to 2.0 wt% taste masking agent
- Taste masking agent is selected from:
- alkali metal chlorides, or
- alkaline earth metal chlorides
Claim 3: Alkali metal chloride species list
Claim 3 specifies:
- alkali metal chloride is selected from:
- sodium chloride
- potassium chloride
- lithium chloride
Claim 4: Sodium chloride embodiment
Claim 4 narrows Claim 3 to:
Claim 5: Alkaline earth chloride species list
Claim 5 specifies:
- alkaline earth metal chloride is:
- magnesium chloride or calcium chloride
What is the legal and practical claim scope?
US 7,175,855 is an excipients-in-range formulation patent. The claim architecture is:
- Product-by-composition (ingredients must be present in defined amounts)
- Functional intent is constrained by ingredient selection and numeric limits
- The salt for taste masking is claimed as a concentration band and a closed genus-to-species hierarchy across dependent claims.
Claim-type implications for enforcement
- The independent claim (1) is broad within its excipient list and ranges. A competitor formulation that matches all required components and stays within those ranges falls within scope.
- Dependent claims (2-5) add narrowing limitations. If a competitor uses a different taste masking agent (not in the cited chloride sets) or outside the 0.5 to 2.0 wt% band, the dependent claims do not read, though Claim 1 may still be implicated if its requirements are met.
Range-based scope and “edge-of-range” exposure
Because the claims use “from about” range language, infringement risk is not binary at a single boundary; it is determined by claim construction and the “about” tolerance applied. Still, the nominal infringement-relevant design space is clearly bounded:
- Polysorbate 80: 0.05 to 0.3 wt%
- Xanthan gum: 0.01 to 10 wt%
- Colloidal silicon dioxide: 0.05 to 2.0 wt%
- Taste masking salt (if invoking claims 2-5): 0.5 to 2.0 wt%, and must be one of the listed chlorides
Built-in formulation “in-scope recipe”
A formulation that satisfies Claim 1 must at minimum be:
- A liquid aqueous ziprasidone HCl composition
- With polysorbate 80 in the specified narrow band
- With xanthan gum spanning a very wide band up to 10%
- With colloidal silicon dioxide in a moderate band
Claim 2 then requires a specific salt class and band:
- Add 0.5 to 2.0 wt% of an alkali or alkaline earth chloride.
Claims 3-5 further restrict the salt selection:
- Alkali chloride species: NaCl, KCl, LiCl
- Alkaline earth chloride species: MgCl2 or CaCl2
How does the dependent-claim ladder narrow the scope?
The dependent-claim chain creates a layered infringement map.
Infringement pathway
A product only needs to match Claim 1 to implicate the patent’s core scope.
To implicate dependent claims:
- It must also match Claim 2’s taste masking salt category and band.
- Then match the specific salt species limitations in Claims 3-5.
Narrowing summary table (ingredient + range + allowed species)
| Claim |
Required taste masking agent |
Taste masking concentration band |
Allowed salt species constraint |
| 1 |
Not required |
N/A |
N/A |
| 2 |
Alkali metal chloride or alkaline earth metal chloride |
0.5 to 2.0 wt% |
Salt must be in chlorides genus |
| 3 |
Alkali metal chloride |
0.5 to 2.0 wt% (inherited) |
NaCl or KCl or LiCl |
| 4 |
Sodium chloride |
0.5 to 2.0 wt% (inherited) |
Must be NaCl |
| 5 |
Alkaline earth metal chloride |
0.5 to 2.0 wt% (inherited) |
MgCl2 or CaCl2 |
Where is the competitive risk highest: design-space hotspots?
For competitors, the highest risk concentrates in excipient selection and numeric bands.
Highest-risk formulation parameters
- Polysorbate 80 at 0.05 to 0.3 wt%
- This is a relatively tight band. Many oral formulations may use surfactants, but not necessarily in this narrow concentration window.
- Colloidal silicon dioxide at 0.05 to 2.0 wt%
- If colloidal silicon dioxide is used, staying outside this band may avoid Claim 1. If within, remaining exposed depends on whether all other Claim 1 requirements are met.
- Xanthan gum at 0.01 to 10 wt%
- This is a wide range. If a competitor uses xanthan gum at typical viscosity-thickening levels, they often fall within the claimed window.
- Taste-masking salt: 0.5 to 2.0 wt%
- If the competitor uses chloride salts for taste masking (NaCl, KCl, LiCl, MgCl2, CaCl2) and lands in the concentration band, Claims 2-5 become relevant.
Design-around levers (scope-relevant, not strategy commentary)
- Replace polysorbate 80 with a different surfactant or alter its level outside 0.05 to 0.3 wt%.
- Use a different thickener system and avoid xanthan gum or keep it outside 0.01 to 10 wt%.
- Avoid colloidal silicon dioxide or keep it outside 0.05 to 2.0 wt%.
- For taste masking: use a non-chloride taste masker or use chloride salts outside 0.5 to 2.0 wt%.
What is the likely patent landscape geometry around this claim set?
The patent landscape for ziprasidone formulations typically clusters into several “families” of protection:
- Active salt and polymorph/solid-state (ziprasidone HCl form selection)
- Compositions for oral administration (liquid, suspension, capsule, tablet)
- Stabilizers and surfactants (surfactants like polysorbates)
- Thickening/rheology systems (xanthan gum, gellan, HPMC, etc.)
- Anti-caking/flow agents (colloidal silicon dioxide)
- Taste masking (salts, sweeteners, microencapsulation, ion-exchange resins)
US 7,175,855 sits at the intersection of:
- liquid aqueous ziprasidone HCl composition
- specific excipient combination: polysorbate 80 + xanthan gum + colloidal silicon dioxide
- optionally a specific taste-masking chloride salt band
How to read the landscape risk for an oral liquid R&D program
For a ziprasidone oral liquid product, a freedom-to-operate search around US 7,175,855 should logically cover:
- other ziprasidone oral solution/suspension patents that claim similar excipient sets or overlapping ranges
- generic excipient formulation patents that might be asserted indirectly (if they claim a composition with the same ingredient combination)
- salt/taste masking patents where chloride-based masking and similar bands appear
- surfactant-stabilized ziprasidone formulations where polysorbate 80 concentration bands are claimed
What would likely be in-scope compared to near-miss designs?
Without external claim text from other patents, “likely” here is about how infringement maps to this patent’s required ingredient set.
Likely in-scope examples (based strictly on the claim logic)
A ziprasidone HCl aqueous composition containing:
- polysorbate 80 within 0.05 to 0.3 wt%
- xanthan gum within 0.01 to 10 wt%
- colloidal silicon dioxide within 0.05 to 2.0 wt%
- and, if taste masking is used: chloride salt within 0.5 to 2.0 wt% and species in Claims 3-5
Likely out-of-scope near misses
- Formulations that omit any of the Claim 1 required excipients
- Formulations that change the salt type outside the chloride sets
- Formulations with chloride salt levels outside 0.5 to 2.0 wt%
- Formulations using a surfactant other than polysorbate 80 (or polysorbate 80 outside the band)
- Formulations that replace xanthan gum with another gelling agent outside the claimed requirement
Claim-by-claim scope statement (tight wording for FTO reviews)
Claim 1 scope
A composition comprising:
- ziprasidone hydrochloride
- water
- polysorbate 80 (0.05 to 0.3 wt%)
- xanthan gum (0.01 to 10 wt%)
- colloidal silicon dioxide (0.05 to 2.0 wt%)
Claim 2 scope
Claim 1 plus:
- 0.5 to 2.0 wt% taste masking agent
- taste masking agent is an alkali metal chloride or alkaline earth metal chloride
Claim 3 scope
Claim 2 plus:
- alkali metal chloride is NaCl, KCl, or LiCl
Claim 4 scope
Claim 3 plus:
- alkali metal chloride is sodium chloride
Claim 5 scope
Claim 2 plus:
- alkaline earth metal chloride is MgCl2 or CaCl2
Key Takeaways
- US 7,175,855 is a ziprasidone HCl aqueous formulation patent with precise excipient concentration ranges in Claim 1.
- The core risk is matching Claim 1’s required ingredient set and concentration bands: polysorbate 80 (0.05-0.3 wt%), xanthan gum (0.01-10 wt%), colloidal silicon dioxide (0.05-2.0 wt%).
- The additional risk in Claims 2-5 turns on taste masking using chloride salts at 0.5 to 2.0 wt% with a closed list of specific species (NaCl/KCl/LiCl or MgCl2/CaCl2).
- Landscape-wise, the patent sits in the middle of formulation-protection clusters for liquid rheology, stabilization, anti-caking/processing aids, and taste masking, so overlapping claims are most likely in ziprasidone oral liquid/suspension domains using similar excipient combinations.
FAQs
1) What formulation type does the patent cover?
An aqueous composition for ziprasidone hydrochloride containing specific excipients: polysorbate 80, xanthan gum, and colloidal silicon dioxide, with optional chloride taste-masking salts.
2) Is taste masking mandatory?
No. Taste masking is only required for Claim 2 and its dependent claims. Claim 1 does not require a taste masking agent.
3) Which excipient range is the tightest in Claim 1?
Polysorbate 80 at 0.05 to 0.3 wt%.
4) Which chloride salts are explicitly covered for taste masking?
Alkali metal chlorides: sodium chloride, potassium chloride, lithium chloride. Alkaline earth chlorides: magnesium chloride and calcium chloride.
5) What concentration must the taste masking agent fall within?
From about 0.5 to about 2.0 wt%.
References
[1] User-provided claim text for US 7,175,855 (Claims 1-5).
