US Patent 5,800,807: Scope, Claim Map, and US Landscape for Glycerin/Propylene Glycol Artificial Tears
What does US Patent 5,800,807 claim, in scope terms?
US Patent 5,800,807 covers ophthalmic compositions and methods built around a narrow, defined physicochemical window for an artificial tear-type formulation. The core independent claim theme is a solution containing glycerin + propylene glycol at specific weight-percent ranges, with defined osmolality and pH.
Claim 1 (core composition)
Independent claim 1 defines an ophthalmic composition comprising:
- Glycerin: about 0.2 to 1.5 wt%
- Propylene glycol: about 0.2 to 1.5 wt%
- Osmolality: about 175 to 330 mOsm/kg
- pH: about 6.0 to 8.0
This claim is broad on:
- excipients (not required)
- buffer system (not required)
- preservatives (not required)
- polymers/demulcents (optional via dependent claims)
Claim 7 (buffered artificial tear composition with cellulose derivative)
Independent claim 7 is an ophthalmic solution for artificial tears with tighter targets:
- Glycerin: about 0.2 to 1.5 wt%
- Propylene glycol: about 0.2 to 1.5 wt%
- Cellulose derivative: about 0.2 to 3.0%
- Borate buffer (required)
- Osmolality: about 280 to 320 mOsm/kg
- pH: about 7.1 to 7.5
Claim 7 is narrower than claim 1 because it adds:
- required buffer identity (borate)
- required cellulose derivative presence and loading
- narrower osmolality/pH ranges
Claim 9 (method claim)
Independent claim 9 covers the use:
- contacting the eye with an ophthalmic composition defined by:
- glycerin 0.2–1.5 wt%
- propylene glycol 0.2–1.5 wt%
- osmolality 175–330 mOsm/kg
- pH 6.0–8.0
- for moisturizing or lubricating the eye
Claim 10 (composition with demulcents defined “consisting essentially of”)
Independent claim 10 recites:
- combination of demulcents consisting essentially of:
- glycerin 0.2–1.5 wt%
- propylene glycol 0.2–1.5 wt%
- osmolality 175–330 mOsm/kg
- pH 6.0–8.0
“Consisting essentially of” is materially limiting: it permits additional components that do not materially change the demulcent composition concept (the claim language pins the demulcent system to glycerin/propylene glycol).
How do dependent claims narrow the formulation perimeter?
Dependent claims layer on polymers, preservatives, and exclusion language.
Polymers and demulcents (Claims 2–3)
- Claim 2: claim 1 plus at least one of:
- cellulose derivative, dextran, gelatin, polyethylene glycol, polysorbate, polyvinyl alcohol, polyvinyl-pyrrolidone
- Claim 3: claim 2 plus a cellulose derivative selected from:
- hydroxypropyl methyl cellulose
- carboxymethyl cellulose
- methyl cellulose
- hydroxyethyl cellulose
Practical scope effect: if a product contains glycerin + propylene glycol in-range and meets the osmolality/pH limits, adding the specified polymer class can move it into the dependent claim set.
Preservative layer (Claims 4–5)
- Claim 4: claim 1 plus a preservative
- Claim 5: claim 4 plus at least one of:
- benzylalkonium chloride
- polyquat
- PHMB
- sorbic acid
Practical scope effect: formulations meeting claim 1 that also use one of these preservatives fall into claims 4–5 (not just claim 1).
Tighter physicochemical specification and bound water (Claim 6)
- pH: 7.1 to 7.5
- osmolality: 280 to 320 mOsm/kg
- at least about 11 percent bound water
Practical scope effect: claim 6 is a “higher bar” version of the physicochemical window, adding a performance/structure metric (bound water). Products often meet osmolality/pH but may not disclose bound-water metrics in a way that is easy to map to this specific claim.
Exclusion claim (Claim 8)
- starts from claim 7
- excludes:
- polyvinylpyrrolidone
- polyvinyl alcohol
- polyethylene glycol
- polyethylene oxide
- polyacrylic acid
- anionic polymers
Practical scope effect: claim 8 is a negative limitation. If a competitor uses any listed excluded polymers/additives, claim 8 no longer reads on that formulation. This can create carve-outs for “dual polymer” or “carboxylate anionic” designs.
Where is the true claim “center of gravity”?
The claim set concentrates around one formulation architecture:
- Humectant pair: glycerin + propylene glycol
- Compatibility window: osmolality 175–330 mOsm/kg, pH 6.0–8.0
- Tighter “market-relevant tear” subset: osmolality 280–320, pH 7.1–7.5
- Add-ons that matter legally:
- borate buffer (claim 7)
- cellulose derivative (claim 7, claim 3)
- preservatives listed in claim 5
- bound water criterion (claim 6)
- negative polymer exclusions (claim 8)
In-range vs out-of-range risk map
- A formulation that meets the glycerin 0.2–1.5 wt% and propylene glycol 0.2–1.5 wt% ranges is positioned to implicate claim 1/9/10 and dependent claim structures.
- The main “escape” levers are:
- pH outside 6.0–8.0 (for claim 1/9/10) or outside 7.1–7.5 (for claim 6/7/8)
- osmolality outside 175–330 mOsm/kg (claim 1/9/10) or outside 280–320 mOsm/kg (claim 6/7/8)
- removing glycerin or propylene glycol from its claimed weight-percent range
- swapping buffers away from borate (to avoid claim 7/8)
- using excluded polymers/additives in claim 8 (to avoid that dependent claim specifically)
What is the likely patent landscape posture in the US (freedom-to-operate logic)?
Without external file-wrapper data for every related family member, the usable landscape inference is structural: 5,800,807 is tightly tied to a defined physicochemical envelope plus specified excipient classes. That typically triggers a landscape dominated by:
- other artificial tear patents that also target humectants and controlled osmolality/pH
- patents about polymeric demulcents and preservatives for tears
- later formulations that adjust buffer systems, polymer chemistry, or osmolality targets to avoid earlier claim windows
Landscape segmentation you should use for an FTO screen
Treat the US landscape as three concentric layers:
-
Humectant core patents (glycerin/propylene glycol)
- Claim 1 and 9 define the humectant pair and its physicochemical conditions.
- Competitor designs that stay in-range on both humectants and meet the same osmolality/pH window create the highest legal overlap risk.
-
“Tear-mimetic” buffer and tonicity patents
- Claim 7 adds borate buffer and narrows osmolality/pH.
- If competitors use different buffers (phosphate, citrate, HEPES) or target different osmolality bands, they can avoid claim 7 while still using glycerin/propylene glycol.
-
Polymer-preservative architectures
- Claim 2/3 expands into cellulose derivatives and selected polymer categories.
- Claim 5 narrows preservatives to a fixed set.
- Claim 8 creates a negative polymer list that can be used as a de-risking design constraint, even if claim 7 is otherwise met.
How to read claim scope as a “claim map” for product formulation decisions
Use this map to test a candidate product against the claim set:
Step 1: Does it hit the core humectant window?
- glycerin 0.2–1.5 wt%
- propylene glycol 0.2–1.5 wt%
If no, most of the claim set drops away.
If yes, proceed.
Step 2: Does it hit claim 1/9 physicochemical boundaries?
- osmolality 175–330 mOsm/kg
- pH 6.0–8.0
If yes, claim 1 (and method claim 9, and demulcent claim 10) are implicated.
If no, check whether claim 6/7 range is met instead.
Step 3: If you want “artificial tear” positioning, check claim 7/8
- add borate buffer
- cellulose derivative 0.2–3.0%
- osmolality 280–320
- pH 7.1–7.5
If yes, claim 7 is implicated; then evaluate claim 8 exclusion list.
Step 4: Preservative and polymer additions
- If a preservative is used, check whether it is in:
- benzylalkonium chloride
- polyquat
- PHMB
- sorbic acid
- If cellulose derivative is used, check whether it matches one of the listed cellulose chemistries in claim 3.
Step 5: Bound water constraint (claim 6)
If the product is engineered and tested to report bound water >= 11%, it can map to claim 6 even when it otherwise aligns with pH/osmolality.
Key “hot spots” where competitors most often intersect the claims
-
Glycerin + propylene glycol in-range
Many artificial tears use one humectant or both. The legal issue is the precise weight percent plus the pH/osmolality window.
-
pH and osmolality targeting to physiologic tear conditions
A formulation engineered toward pH 7.1–7.5 and osmolality 280–320 often lands inside claim 6 and claim 7.
-
Borate buffering with cellulose viscosity systems
Borate + cellulose derivative at 0.2–3.0% is a specific combination that can be uncommon relative to phosphate-buffered systems.
-
Preservative system selection
Preservatives like benzalkonium chloride and PHMB are common across ophthalmic compositions. Claim 5 makes that common choice a direct mapping target when claim 1 is met.
-
Negative polymer list (claim 8)
If developers use polymers that include anionic character (e.g., certain polyacrylic acid-based systems), they can inadvertently avoid claim 8 but still fall under claim 7 or claim 1/2 depending on polymer inclusion and claim interpretation.
Key Takeaways
- US 5,800,807 is built around a defined ophthalmic formulation window: glycerin 0.2–1.5 wt% + propylene glycol 0.2–1.5 wt% with osmolality 175–330 mOsm/kg and pH 6.0–8.0 (claims 1/9/10).
- The litigation-relevant narrowing subset is claim 7: borate buffer + cellulose derivative (0.2–3.0%) with osmolality 280–320 mOsm/kg and pH 7.1–7.5.
- Claim 8 creates an exclusionary dependent claim tied to the claim 7 scaffold, limiting certain polymers/additives.
- The main FTO risk levers are: humectant wt%, pH, osmolality, borate vs other buffers, cellulose derivative presence and identity, and preservative choice (benzalkonium chloride, polyquat, PHMB, sorbic acid).
- If a competitor product stays within the humectant window and targets physiologic tear osmolality/pH, it most directly collides with claim 1/6/7.
FAQs
1) Which claim is the broadest entry point for potential infringement?
Claim 1 (and method claim 9) because it only requires glycerin + propylene glycol at the stated wt% levels and the osmolality/pH ranges, without requiring buffer identity, cellulose, or preservatives.
2) What formulation element most sharply narrows scope besides pH and osmolality?
For the artificial tear embodiment, borate buffer plus cellulose derivative (0.2–3.0%) in claim 7.
3) Do preservatives matter for the base protection?
Not for claim 1. Preservatives are only required in dependent claim 4 and constrained by claim 5 to a defined list.
4) How does claim 8 affect freedom to operate?
It can provide a dependent-claim carve-out if the formulation includes any of the expressly excluded polymers/additives listed in claim 8, even when it otherwise meets claim 7’s structure and physicochemical ranges.
5) What is the role of bound water in this patent?
Claim 6 requires at least about 11% bound water alongside tighter pH/osmolality ranges, adding an extra technical criterion beyond the basic composition ranges.
References (APA)
[1] United States Patent No. 5,800,807. (n.d.). Ophthalmic compositions and methods of using same.
