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Patent landscape, scope, and claims: |
United States Patent 10,479,686: Scope, Claims, and Patent Landscape for Sodium Thiosulfate Pentahydrate Parenteral Compositions
What does US 10,479,686 claim protect?
US 10,479,686 protects a very tightly specified parenteral pharmaceutical composition built around a single active material: sodium thiosulfate pentahydrate meeting stringent quality attributes and performance visuals/functional parameters, plus formulation flexibility via pharmaceutically acceptable excipients.
The claims are structured to (1) define the material spec for the sodium thiosulfate pentahydrate, (2) constrain composition physical and analytical properties (appearance, pH, water content, impurity limits, microbial/endotoxin limits), and (3) require parenteral formulation with at least one pharmaceutically acceptable carrier or excipient, with examples that span vehicles and typical parenteral excipient classes.
What is the independent claim 1 scope?
Claim 1 is the core. It is a closed set on the active’s quality specification and key solution properties, while being open on the excipient selection (it “comprises” a sodium thiosulfate pentahydrate plus one or more carriers/excipients, where the carrier/excipient may be any listed class).
1) Active ingredient must meet a defined sodium thiosulfate pentahydrate profile
Claim 1 requires sodium thiosulfate pentahydrate with all of the following constraints:
(a) Carbon / mercury / elemental impurity limits
- Non-purgeable organic carbon: ≤ 8 ppm
- Mercury: ≤ 0.05 ppm
- Aluminum: ≤ 2 ppm
- Heavy metals: ≤ 10 ppm
- Selenium: ≤ 0.003% by weight
- Arsenic: ≤ 3 ppm
- Lead: ≤ 0.001% by weight
- Iron: ≤ 0.002% by weight
- Calcium: ≤ 0.01% by weight
- Potassium: ≤ 0.005% by weight
(b) Sulfur species and other inorganic anions
- Sulfide: ≤ 0.001% by weight
- Chloride: ≤ 200 ppm
- Sulfite: ≤ 0.1% by weight
- Sulfate: ≤ 0.5% by weight
- Nitrogen compounds: ≤ 0.002% by weight
- Residual anti-caking agent: ≤ 0.01% by weight
- Insoluble matter: ≤ 0.005% by weight
(c) Microbial and endotoxin limits
- Total aerobic count: ≤ 100 CFU/g
- Total yeast and mold: ≤ 20 CFU/g
- Bacterial endotoxins: ≤ 0.02 EU/mg
(d) Identity and assay purity (sodium thiosulfate content)
- Sodium thiosulfate (anhydrous basis), by ion chromatography:
- ≥ 98% by weight
- ≤ about 102% by weight
(e) Water content requirement
- Water content: 32% to 37% by weight
(f) Organic volatile impurities
- Organic volatile impurities: ≤ ICH Q3C (R3) limits
(g) Solution behavior and appearance
- A 10% aqueous solution of the solid at 25°C:
- colorless
- pH between 6.0 and 8.0
(h) Solid-state appearance
- Solid sodium thiosulfate pentahydrate:
2) Formulation must be for parenteral administration
Claim 1 requires:
- “The pharmaceutical composition is formulated for parenteral administration.”
- The carrier/excipient is an aqueous vehicle; a water-miscible vehicle; a non-aqueous vehicle; an antimicrobial agent/preservative; a stabilizer; a solubility enhancer; an isotonic agent; a buffering agent; an antioxidant; a local anesthetic; a suspending/dispersing agent; a wetting/emulsifying agent; a complexing agent; a sequestering/chelating agent; a cryoprotectant; a lyoprotectant; a thickening agent; a pH adjusting agent; or an inert gas.
This makes claim 1 a quality-spec driven protection. Even if a competitor uses different excipient selections inside those listed classes, they can still infringe if the active’s material spec and 10% solution behavior match.
3) Composition is not limited to a specific dosage form in claim 1
Claim 1 describes a parenteral composition generally. Dependent claims narrow to certain packaging/forms (see below).
How do dependent claims narrow scope?
Claims 2 to 21 add additional limitations that slice the claim space into identifiable commercially relevant embodiments.
Claims 2-3: Identity tests
- Claim 2: positive identification test for sodium
- Claim 3: positive identification test for thiosulfate
These are additional “must-pass” confirmations tied to the same active material.
Claims 4-21: Dosage form and excipient-type selection
Dosage form
- Claim 4: composition is a single dosage form
Vehicle selection
- Claim 5: aqueous vehicle
- Claim 6: aqueous vehicle is one of:
- water, saline, physiological saline, phosphate buffered saline, sodium chloride injection, Ringers injection, isotonic dextrose injection, sterile water injection, dextrose, lactated Ringers injection
Non-aqueous vehicle
- Claim 7: fixed oil of vegetable origin or specific oils including:
- castor oil, corn oil, cottonseed oil, olive oil, peanut oil, peppermint oil, safflower oil, sesame oil, soybean oil
- hydrogenated vegetable oil, hydrogenated soybean oil
- medium-chain triglycerides of coconut oil
- palm seed oil
Water-miscible vehicle
- Claim 8: ethanol, 1,3-butanediol, liquid PEG, propylene glycol, glycerin, NMP, DMAc, DMSO
- Claim 9: PEG specified:
Antimicrobial / preservative options
- Claim 10: phenol, cresol, mercurial, benzyl alcohol, chlorobutanol, parabens (methyl/propyl p-hydroxybenzoate), thimerosal, benzalkonium chloride, benzethonium chloride, methyl-paraben, propyl-paraben, sorbic acid
Isotonic agents
- Claim 11: potassium chloride, mannitol, sodium chloride, dextran, glucose, glycerin, dextrose
Buffering
- Claim 12: phosphate or citrate
Antioxidant
- Claim 13: bisulfite or sodium metabisulfite
Local anesthetic
- Claim 14: procaine hydrochloride
Suspending/dispersing
- Claim 15: sodium carboxymethylcellulose, HPMC, PVP
Emulsifying agent
- Claim 16: polysorbate-type surfactants and related:
- polyoxyethylene sorbitan monolaurate
- polyoxyethylene sorbitan monooleate 80
- triethanolamine oleate
Chelating/sequestering
pH adjusting
- Claim 18: acid or base
- Claim 19: acid is boric acid, hydrochloric acid, citric acid, or lactic acid; base is sodium hydroxide
Complexing agent
Cyclodextrin species
- Claim 21: α-cyclodextrin, β-cyclodextrin, hydroxypropyl-β-cyclodextrin, sulfobutylether-β-cyclodextrin, sulfobutylether 7-β-cyclodextrin
What is the practical enforcement strategy implied by these claims?
The claim architecture prioritizes spec-based exclusivity rather than a novel excipient system.
Infringement hinges on the supplier-grade sodium thiosulfate pentahydrate
A manufacturer cannot “design around” by swapping buffers, isotonic agents, or solubilizers if:
- the sodium thiosulfate pentahydrate meets the full analytical set; and
- the resulting 10% aqueous solution is colorless and pH 6.0 to 8.0 at 25°C; and
- the microbial/endotoxin and inorganic/organic impurity boundaries are met.
Excipients are broadly covered
Claim 1 uses a class-based open “wherein the pharmaceutically acceptable carrier or excipient is…” list. That list mirrors typical parenteral formulation components, including vehicles and preservatives, so an excipient swap is unlikely to avoid claim 1 if the active spec is matched.
Dependent claims support narrower “product embodiments”
Claims 4-21 create fallback positions tied to:
- single dosage form,
- specific vehicle families (aqueous, non-aqueous oil, water-miscible solvents),
- specific preservative/buffer/antioxidant/chelators, and
- pH adjustment chemistry.
Where is the patent landscape likely to be crowded vs. thin?
Without adding external records beyond the claim text you provided, the landscape read is constrained to what the claim itself signals.
Likely crowded space
- Parenteral formulation excipient classes: The excipient list in claim 1 is broad and conventional. Many competitors can converge on similar excipient packages.
- Basic identity and assay concepts: standard identity tests for sodium and thiosulfate and general assay ranges tend to be widely used across pharmacopeial material.
Likely thinner space
- The combined impurity + microbial + physical behavior bundle on sodium thiosulfate pentahydrate:
- non-purgeable organic carbon cap,
- multi-element impurity ceilings (Al, Hg, As, Pb, Fe, Ca, K, Se),
- sulfur species ceilings (sulfide/sulfite/sulfate),
- endotoxin and microbial CFU thresholds,
- plus a specific water content window (32%-37%),
- plus 10% solution pH 6.0-8.0 and colorless at 25°C,
- plus odorless crystals,
- plus compliance with ICH Q3C (R3) organic volatile limits.
That combination is a high bar for both manufacturing and vendor qualification, and it acts as the core differentiator.
Key claim elements mapped to manufacturing controls
This is how the patent scope translates into audit points.
| Claim requirement |
Manufacturing control implication |
Competitive risk if missed |
| Organic carbon (≤ 8 ppm, non-purgeable) |
Carbon contamination control during purification and drying; process qualification |
High: direct claim failure |
| Hg (≤ 0.05 ppm), Al (≤ 2 ppm), heavy metals ≤ 10 ppm |
Metallurgical contaminant control; incoming raw material spec |
High |
| Se ≤ 0.003%, As ≤ 3 ppm, Pb ≤ 0.001%, Fe ≤ 0.002% |
Multi-element spec and analytical panel at lot release |
High |
| Chloride ≤ 200 ppm; sulfide ≤ 0.001%; sulfite ≤ 0.1%; sulfate ≤ 0.5% |
Control of ionic residues and oxidation state carryover |
High |
| Water content 32%-37% |
Drying endpoint control; hygroscopicity management |
Medium to high |
| 10% solution colorless; pH 6.0-8.0 at 25°C |
Dissolution profile control; impurity-driven pH shifts; solution clarity |
High |
| Total aerobic ≤ 100 CFU/g; yeast/mold ≤ 20 CFU/g; endotoxin ≤ 0.02 EU/mg |
Bioburden and endotoxin control, sterile-like grade even if non-sterile in product |
High |
| ICH Q3C (R3) organic volatiles |
Solvent and residual volatile management |
Medium to high |
| Residual anti-caking ≤ 0.01%; insoluble matter ≤ 0.005% |
Anti-caking additive control; filtration/size control |
Medium |
What is the decision-relevant “design-around” surface?
Given the claim set, viable design-around routes (conceptually) would need to fail at least one of the following required attributes:
- Material impurity limits (any of the listed elements/analytes)
- Sulfur species ceilings (sulfide/sulfite/sulfate)
- Bioburden/endotoxin limits
- Water content window
- 10% solution color and pH at 25°C
- ICH Q3C volatile impurities compliance
- The odorless crystalline requirement (if treated as enforceable)
In contrast, swapping excipients listed in claims 5-21 appears to preserve claim 1 coverage unless the excipient change alters one of the constrained active/spec-linked attributes (for example, if excipients affect solution pH at the stated 10% condition, though claim 1 attributes are framed on the “solid sodium thiosulfate pentahydrate” and a 10% aqueous solution of the solid, suggesting active-driven properties).
Key Takeaways
- US 10,479,686 claim 1 is primarily a sodium thiosulfate pentahydrate quality-spec claim: impurity ceilings, microbial/endotoxin limits, water content window, volatile impurity compliance, and defined 10% solution clarity and pH at 25°C.
- Parenteral formulation is required, but excipient selection is broad across conventional parenteral vehicles, preservatives, isotonic agents, buffering agents, stabilizers, and related classes.
- Dependent claims add product embodiment constraints (single dosage form and specific vehicle/excipient families), supporting enforcement against specific marketed packaging and formulation selections.
- The enforcement surface is lot release testing and dissolution behavior, not excipient novelty.
FAQs
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Is the patent about a specific excipient formulation?
Claim 1 is not limited to a novel excipient system; it focuses on sodium thiosulfate pentahydrate that meets extensive impurity, microbial, and solution property constraints for parenteral use.
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Can a competitor avoid infringement by changing buffers or preservatives?
Changing excipients can fail to avoid claim 1 if the sodium thiosulfate pentahydrate still meets all required quality parameters and the 10% solution properties (colorless, pH 6.0-8.0 at 25°C) are met.
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What is the single most enforceable technical linkage in claim 1?
The combined analytical specification of the sodium thiosulfate pentahydrate, especially impurity ceilings plus bioburden/endotoxin limits and the 10% solution color and pH requirements.
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Do the dependent claims narrow the scope enough to be considered separate patents?
They narrow embodiments within the same invention by adding constraints (identity tests, dosage form, and specific vehicle/excipient selections), but they remain anchored to the same foundational sodium thiosulfate quality requirements of claim 1.
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Does the patent require a specific cyclodextrin type?
No; cyclodextrin is optional via claim 20, and claim 21 specifies particular cyclodextrin species only when that dependent claim is invoked.
References
[1] US Patent 10,479,686, claims 1-21 (provided claim text).
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