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Patent landscape, scope, and claims: |
US Patent 5,881,926: Scope of Claims and Patent-Landscape Readout
United States Patent 5,881,926 is a non-spill oral delivery system built around a squeezable semisolid dose and a unvented channel closure that reseals between dispensing events. Claim scope concentrates on three coupled elements: (1) device mechanics that prevent spill-out during handling and dosing, (2) a tamper-evident closure/seal regime, and (3) a storage-stable, squeezeable semisolid vehicle defined by solvent/thickener ranges and Brookfield viscosity.
What do the independent claims cover?
The claim set is dominated by apparatus/system claims with broad structural coverage and layered formulation constraints. The “center of mass” is the pairing of a squeezable container with a dispenser that has an unvented, resealable channel closure actuated by a spring-biased step cylinder (and later claim variants cover alternative valve/closure geometries and alternate container formats).
Independent claim themes (structural + formulation tether)
Across claims 1, 2, 4, 13, 22, and 36, the minimum reusable core is:
- Container: squeezable container with an outlet defining a flow channel.
- Dispenser/closure: unvented channel closure device with closed/open positions that reseals when not actuated.
- Actuation: spring-biased step cylinder (step-cylinder variants; rotatable/pivotable/rotatable variants appear later).
- Tamper evidence: tamper-evident seal over the closure cavity that breaks when actuated/opened.
- Dose: at least one dose of a storage-stable semisolid with a defined vehicle and rheology.
- Delivery performance statement: a predetermined unit dose dispensed by squeezing without spilling into container or receptacle.
- Formulation rheology: Brookfield viscosity target window at specified spindle speed and temperature.
The “device” and “formulation” are repeatedly coupled: claims do not just claim the dispenser; they also specify the semisolid composition being squeezeable under manual pressure and meeting the Brookfield range.
What is the core mechanical claim scope?
Spring-biased unvented channel closure (claims 1-3, 22, 29-31)
The most specific mechanical embodiment is:
- Unvented channel closure device with closed/open positions.
- Closure comprises a spring biased step cylinder positioned in the dispenser.
- Channel means allow passage from the squeezable container only when the cylinder is pressed.
- When not pressed, the cylinder reseals the squeezable container outlet/channel.
- The cylinder is described as rotatable in dependent claim 3, with:
- cylinder having channel means and an outside button,
- a cavity in the dispenser configured to accept the button,
- depression permitted only when the button is aligned with the cavity.
Claim 29 further broadens closure architecture:
- “Valve positioned in said dispenser capable of allowing passage … when in the open position and resealing … when in the closed position.”
- Dependent claim 30 covers rotatable valve; claim 31 covers pivotable valve.
Tamper-evident seal regime (claims 1, 2, 22, 23)
Tamper-evidence appears as:
- “a tamper-evident seal of the channel closure device,” and
- in the detailed embodiment: “a plastic covering over said cavity which prevents tampering … before use, and which is broken when the cylinder is depressed.”
Claim 23 tightens the operational rule:
- opening the channel closure requires at least two separate manipulations
- and the tamper-evident seal breaks the first time the closure device is opened.
Flow channel and internal diameter constraint (claims 4, 13)
The device is constrained by an internal channel diameter:
- Claim 4: outlet/channel internal diameter 0.1 mm to 5 mm.
- Claim 13: channel internal diameter 0.1 mm to 5 mm.
This is material because it limits nozzle/orifice geometry that affects spill control and dose consistency.
What is the core formulation claim scope?
The semisolid formulation is not generic. The vehicle is defined by liquid base, thickener, and rheology.
Vehicle components and ranges (claims 1, 2, 13, 22)
- Liquid base (palatable solvent): water, propylene glycol, polyethylene glycol, glycerin, and mixtures
- Liquid base amount: about 45 wt% to about 95 wt%
- Thickening agent: starch, modified starch, sodium carboxymethyl cellulose, microcrystalline cellulose, hydroxypropyl cellulose, other cellulose derivatives, acacia, tragacanth, pectin, gelatin, polyethylene glycol, water-soluble carboxyvinyl polymers
- Thickener amount: about 1 wt% to about 55 wt%
Brookfield viscosity and squeezeability (claims 1, 2, 13, 22, 27)
- Brookfield viscosity: about 2500 to about 70,000 cps
- Temperature: about 20°-25° C. (claims vary between “20°-25° C.” and “25° C.”)
- Spindle speed: 10-20 rpm (claim 13 specifies 10 rpm)
- Consistency allows squeezing through the channel by manual pressure.
Claim 27 narrows viscosity:
- viscosity between about 7,500 and about 40,000 cps.
Thickener and vehicle sub-ranges (claims 9-12, 18-20, 24-25, 32-35)
The set includes additional dependent ranges and ingredient combinations that act as “fallback positions”:
- Claim 9: cellulose derivative thickener 2.4 to 3.3 weight % by volume (note unit text inconsistency appears, but range is explicit).
- Claim 10:
- polyethylene glycol thickener 72 to 85 wt% by volume, or
- mixture: polyethylene glycol 10 to 25 wt% by volume plus cellulose derivative 2.5 to 3.3 wt% by volume.
- Claim 24: thickener is polyethylene glycol.
- Claim 25: composition further comprises hydrogenated glucose > about 6.5%.
- Claim 32: liquid base comprises propylene glycol and glycerin; thickener comprises water soluble carboxyvinyl polymer.
- Claim 33:
- propylene glycol + glycerin concentration about 29%
- carboxyvinyl polymer up to about 1%.
- Claim 34-35: glycerin + sorbitol base; thickener sodium carboxymethylcellulose + microcrystalline cellulose
- Claim 35 specifies:
- sorbitol as solution ~70% in water
- glycerin and sorbitol solution ~40%
- carboxymethylcellulose 2.4%
- microcrystalline cellulose 0.9%.
Drug agent breadth (claims 11-12, 20-21)
Claims list wide drug classes and specific examples, functioning more like “intended-use” coverage while still requiring the formulation to be compatible:
- Classes: analgesic, NSAID, antihistamine, cough suppressant, expectorant, bronchodilator, anti-infective, CNS active drug, cardiovascular drug, antineoplastic, cholesterol-lowering drug, anti-emetic, vitamin/mineral supplement, fecal softener.
- Examples include: acetaminophen, aspirin, ibuprofen, diphenhydramine, dextromethorphan, guaifenesin, pseudoephedrine, carbidopa, levodopa, terfenadine, ranitidine, ciprofloxacin, triazolam, fluconazole, propranolol, acyclovir, fluoxetine, enalapril, diltiazem, lovastatin and salts/esters.
Claims 20-21 mirror this but with a slightly different example roster (e.g., propranolol, omitting some like carbidopa/levodopa in that particular list).
How do receptacle and dosing-measurement constraints expand the scope?
Claims tie dispensing to a receptacle sized for unit dose measurement.
- Claim 4: receptacle positioned to receive material dispensed from channel.
- Claim 5: receptacle is a measuring spoon connected to the channel, sized to hold unit dose.
- Claim 6: receptacle is a spoon bowl attached to the dispenser.
Separately, claim 13 and claim 41 cover measuring/squeezing into spoon geometries.
Claim 41 describes:
- a container with open neck and a cap,
- a spoon with shaft and channel means fixed in the cap,
- sealing means that seal container when cap fully closed,
- cap partially opened enables contents to flow through channel into the spoon bowl,
- a pin inside channel rests against the container neck to seal when cap fully closed.
This claim 41 shifts the actuation basis from “spring-biased step cylinder in dispenser” to cap-thread partial engagement and internal pin seal, while keeping the semisolid viscosity constraint.
What are the alternate product-format claim paths?
Two alternate device formats appear:
Flexible packet format (claims 36-40, 37-40)
Claim 36 claims:
- flexible packet torn/cut to open a channel
- a single dose of semisolid composition contained within packet
- on tearing and squeezing, dose dispensed into mouth without spill
Claims 37-40 narrow composition examples:
- propylene glycol + glycerin with water-soluble carboxyvinyl polymer (claims 37-38)
- glycerin + sorbitol with sodium carboxymethylcellulose + microcrystalline cellulose (claims 39-40).
Squeezable flexible tube/container format (claim 28)
Claim 28: “container is a flexible tube.”
Where does the patent landscape sit for “non-spill oral semisolid delivery”?
Infringement sensitivity: the closure and reseal mechanics drive coverage
For infringement targeting, the most critical elements are:
- Unvented channel closure with reseal behavior between open states (claims 1/2/4/13/22/23).
- Spring-biased step cylinder or equivalent valve behavior that reseals (claims 1-3, 29-31).
- Tamper-evident seal that breaks on first actuation and optionally requires “at least two manipulations” (claims 1/2/22/23).
- Channel dimensions (0.1 mm to 5 mm) (claims 4 and 13).
- Formulation rheology: Brookfield 2,500 to 70,000 cps at 20-25 °C and 10-20 rpm, and squeezeability (claims 1/2/13/22, plus dependent viscosity narrowing 27).
Freedom-to-operate sensitivity: viscosity and thickener ranges are differentiators
Because the claims tether device function to a particular semisolid vehicle with explicit rheology, product designers can partially differentiate via:
- outside Brookfield viscosity window (2,500 to 70,000 cps), or
- different thickener system not within the listed thickener definitions (or outside the dependent ranges like cellulose derivative 2.4 to 3.3 or PEG range), or
- a formulation that does not allow manual squeezing through the specified channel dimensions without spill.
The flip side: the thickener lists are broad and include cellulose derivatives and water-soluble carboxyvinyl polymers; viscosity ranges are wide enough that many semisolid oral liquids could fall inside.
Patent landscape mapping (what can be inferred from claim structure)
Without external file histories, the only defensible landscape read is claim-positioning relative to typical non-spill dispensing systems:
- Device-mechanics-heavy protection: the claims read like a mechanical dispensing platform with a formulation rheology constraint. That structure commonly blocks “design-around” only if the closure mechanics and rheology are both matched.
- Fallback ladders exist: rotatable step cylinder, pivotable/rotatable valve alternatives, cap-thread pin seal embodiment, alternate packet format, and explicit vehicle recipes.
- Broad drug payload coverage: drug class lists are extensive, so the payload is unlikely to be a distinguishing parameter unless the formulation vehicle falls outside the specified semisolid Brookfield and vehicle ranges.
Detailed claim-scope inventory (selected claims, consolidated)
(Only claims and limitations provided in the prompt are used.)
Claim 1 (most detailed mechanical + formulation + rotatable cylinder embodiment)
Key limitations:
- squeezable container outlet defining flow channel
- dispenser connected to container with:
- channel communicating with outlet
- unvented channel closure device with closed/open positions
- spring-biased step cylinder reseals when not pressed
- tamper-evident seal of channel closure device
- semisolid composition:
- liquid base 45-95 wt%
- thickener 1-55 wt%
- Brookfield 2,500-70,000 cps at 20°-25 °C and 10-20 rpm
- predetermined unit dose squeezed without spill
- spring-biased step cylinder specifically:
- rotatable spring biased step cylinder
- channel means and outside button
- cavity matched to button
- depression only when button aligned with cavity
- tamper-evident seal includes plastic covering over cavity broken when cylinder depressed
Claim 3 (rotatable step cylinder alignment constraint)
- rotatable step cylinder with channel means and outside button
- dispenser cavity configured so button fits
- depression permitted only when button aligned with cavity
Claim 4 (channel diameter + receptacle + formulation vehicle list)
- container outlet internal diameter 0.1 mm to 5 mm
- unvented channel closure device
- receptacle positioned to receive dispensed material
- semisolid storage stable palatable vehicle:
- liquid base and thickener selected from cellulose starch/cellulose derivatives and carbomer list
- unit dose squeezed into receptacle, measured, administered without spill
Claim 13 (broad apparatus + explicit “two separate manipulations” sealing rule)
- semisolid dose composition with Brookfield 2,500-70,000 cps at 25 °C and spindle speed about 10 rpm
- squeezable means containing and dispensing substantially all composition
- dispenser channel diameter 0.1-5 mm
- tamper evident sealing means
- reseal opens requiring at least two separate manipulations
- unit dose squeezed into receiving means measured and administered orally without spill
Claim 22 (broad independent platform similar to claim 1/2, but less rotatable specificity)
- unvented channel closure device closed/open
- tamper evident seal
- semisolid vehicle Brookfield 2,500-70,000 cps at 20°-25 °C
- unit dose dispensed without spill
Claim 23 (seal-breaking and manipulation count)
- opening requires at least two separate manipulations
- tamper-evident seal breaks first time closure opened
Claim 36 (flexible packet single-dose)
- flexible packet torn or cut to open a channel
- single dose contained within packet
- squeezing dispenses into mouth without spill
- semisolid vehicle: 45-95 wt% liquid base + 1-55 wt% thickener and same Brookfield platform constraints by implication through the claim text
Claim 41 (cap + spoon-channel + pin seal architecture)
- squeezable container with open neck and cap
- spoon with shaft and channel means fixed in cap
- sealing means:
- pin inside channel means projecting into cap
- pin rests against neck and seals when cap fully closed due to thread engagement
- allows passage when threads partially engaged
- composition Brookfield 2,500-70,000 cps at 25 °C at spindle speed 10 rpm
Key takeaways
- The patent is a platform claim: non-spill oral semisolid dispensing relies on unvented resealable closure mechanics plus a squeezeable semisolid vehicle with explicit Brookfield viscosity and vehicle component ranges.
- The most enforceable claim elements are the combination of:
- spring-biased step cylinder (or equivalent valve) that reseals, and
- tamper-evident seal with defined opening behavior, and
- semisolid vehicle within the listed solvent/thickener ranges and Brookfield viscosity window.
- The claims provide design-around pressure points: channel diameter (0.1-5 mm), viscosity bounds, and closure/actuation geometry (step cylinder alignment vs valve types vs cap-thread pin seal).
- Drug payload coverage is broad; the formulation rheology and delivery mechanics are the discriminators.
FAQs
1. What is the single most important mechanical feature in 5,881,926?
The system uses an unvented channel closure device with closed/open positions that reseals the squeezable container between dispensing events, actuated by a spring-biased step cylinder (or equivalent valve embodiments).
2. Does the patent claim specific drugs?
It lists many drug classes and examples, including common OTC and prescription actives, but claim coverage is primarily platform-based. The payload matters less than whether the vehicle and viscosity meet the claim-defined semisolid requirements.
3. How is “non-spill” achieved in the claims?
By coupling resealing closure mechanics (unvented reseal between open states) with a channel/receptacle arrangement and a squeezeable semisolid that dispenses as a unit dose without spill from container or receptacle.
4. What formulation property is explicitly claimed?
Brookfield viscosity: about 2,500 to 70,000 cps at 20°-25 °C and 10-20 rpm (or 25 °C at about 10 rpm in some claims), tied to manual squeeze through the channel.
5. What are the main dependent-claim fallbacks?
Rotatable step cylinder alignment (claim 3), valve variants (claims 29-31), viscosity narrowing (claim 27), thickener-specific ranges (claims 9-10, 18-20), alternative vehicle/ingredient recipes (claims 32-35, 24-25), flexible packet format (claims 36-40), and cap-thread pin seal + spoon-channel embodiment (claim 41).
References
[1] United States Patent No. 5,881,926. Claims as provided in the prompt.
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