Scope, Claims, and Patent Landscape for US Drug Patent 4,550,022

What does US 4,550,022 claim at the product level?

US 4,550,022 is directed to a two-part, sterile, prepackaged tissue irrigating product for use during surgery, where a stable basic solution is aseptically mixed with a stable acidic solution to form a defined irrigating solution with controlled composition, pH, and osmolality. The claim set tightly constrains (1) the two-solution split of components, (2) the target ionic and molecular concentrations after mixing, and (3) the device and handling method used to mix under aseptic conditions.

Independent claim anchor (Claim 1): the compositional envelope

Claim 1 defines:

A. Product form

“A two-part tissue irrigating product”
Stable, sterile, prepackaged basic solution (contains bicarbonate ions; also at least one of several cations/anion requirements are assigned across at least one solution)
Stable, sterile, prepackaged acidic solution (contains dextrose, glutathione, calcium ions, magnesium ions)
Solutions are mixed during surgery to generate the irrigating solution

B. Post-mix composition ranges (irrigating solution)

Sodium ions (Na+): about 130 to 180 mM/L
Potassium ions (K+): about 3 to 10 mM/L
Calcium ions (Ca2+): about 1 to 5 mM/L
Magnesium ions (Mg2+): about 0.5 to 4 mM/L
Bicarbonate ions (HCO3-): about 10 to 50 mM/L
Dextrose: about 2 to 10 mM/L
Oxidized glutathione (or equivalent reduced glutathione): about 0.03 to 0.5 mM/L
pH: about 6.8 to 8.0
Osmolality: about 250 to 350 mOsm/kg

C. The anion/cation presence requirements are split broadly across at least one solution

at least one solution contains sodium ions
at least one solution contains potassium ions
at least one solution contains chloride ions

D. Functional/technical result requirement

The mixed irrigating solution has the specified pH and osmolality plus the specified electrolyte and solute concentrations.

Dependent claims: narrowing points that define competitive design space

Claims 2 to 14 add incremental constraints:

Phosphate constraint (Claims 2 and 8)

Phosphate ions are added such that phosphate in the mixed irrigating solution is 1 to 5 mM/L.

Dedicated pH sub-ranges (Claims 7, 9, 12, 13)

Claim 7: mixed product pH 7.2 to 7.8
Claim 9 (when phosphate included): basic solution pH 7.2 to 7.8 and acidic solution pH below 5
Claims 12 and 13 (when specific salts are used): basic solution pH 7.2 to 7.8; acidic solution pH below 5

Osmolality sub-range (Claim 6)

When claim 3 is used: osmolality 290 to 320 mOsm/kg.

Volume ratio constraint (Claims 10 and 14)

basic:acidic volume ratio 10:1 to 40:1.

Specific salt embodiment (Claims 11 and 3)

Claim 11 is a specific chemistry implementation:

Basic solution contains:
- sodium chloride
- potassium chloride
- dibasic sodium phosphate
- sodium bicarbonate
Acidic solution contains:
- calcium chloride
- magnesium chloride
- dextrose
- oxidized glutathione
Then additional constraints on pH (basic 7.2-7.8; acidic below 5) and volume ratio (10:1 to 40:1) can apply via dependent claims.

Claim 3 provides an alternative “named” split at the component level:

Basic: bicarbonate + sodium + potassium (plus at least one chloride in one of the solutions)
Acidic: calcium + magnesium + dextrose + glutathione (plus at least one chloride in one of the solutions)
Then it re-states the same post-mix concentration envelopes and pH/osmolality envelopes as Claim 1.

Allocation of ions to specific solution (Claims 4 and 5)

Claim 4: sodium ions are contained in basic solution.
Claim 5: potassium ions are contained in basic solution.

These two allocation claims matter for designing around the formulation split even if the post-mix totals are unchanged.

What does Claim 15 expand into: device, package, and mixing method scope?

Claim 15 is an article of manufacture claim that adds the physical article elements and mixing mechanism. It requires:

Package containing stable, sterile basic solution
- “containing bicarbonate ions, sodium ions and potassium ions”
- solution is maintained under vacuum
Vial containing stable, sterile acidic solution
- contains calcium ions, magnesium ions, dextrose, and glutathione
- closed with a rubber stopper
Sterile double-ended needle
A specific aseptic mixing method:
- aseptically insert one end of double-ended needle into basic solution package
- insert other end into acidic vial
- transfer acidic solution into basic solution by vacuum
Mixing produces the same post-mix irrigating solution specification:
- Na 103 to 108 mM/L (note: narrower and different from Claim 1’s 130 to 180 mM/L range)
- K 3 to 10 mM/L
- Ca 1 to 5 mM/L
- Mg 0.5 to 4 mM/L
- HCO3 10 to 50 mM/L
- dextrose 2 to 10 mM/L
- oxidized glutathione 0.03 to 0.5 mM/L
- pH 6.8 to 8.0
- osmolality 250 to 350 mOsm/kg
Chloride presence requirement is retained (“at least one of said solutions containing chloride ions”).

Claim 16 narrows Claim 15 further

phosphate in mixed solution 1 to 5 mM/L.

Key implication: the article claim is not merely “a two-part irrigant.” It is the two-part system packaged under vacuum with a double-ended needle to drive transfer. A competitor who uses different transfer mechanics, different mixing devices, or does not rely on vacuum transfer does not avoid Claim 1, but it can avoid Claim 15’s more specific device/method scope.

How do the claims map to implementable product design constraints?

The claim set defines three layers of technical scope:

Layer 1: post-mix formulation envelope (core technology)

Claim 1 and Claim 3 enforce a specific irrigating-solution “target space”:

Parameter (mixed irrigating solution)	Claim 1 / 3 range
Na+	130 to 180 mM/L
K+	3 to 10 mM/L
Ca2+	1 to 5 mM/L
Mg2+	0.5 to 4 mM/L
HCO3-	10 to 50 mM/L
Dextrose	2 to 10 mM/L
Glutathione (oxidized or reduced equivalent)	0.03 to 0.5 mM/L
pH	6.8 to 8.0
Osmolality	250 to 350 mOsm/kg

Claim 15 uses a distinct Na+ range:

Parameter (mixed irrigating solution)	Claim 15 range
Na+	103 to 108 mM/L
K+	3 to 10 mM/L
Ca2+	1 to 5 mM/L
Mg2+	0.5 to 4 mM/L
HCO3-	10 to 50 mM/L
Dextrose	2 to 10 mM/L
Glutathione (oxidized or reduced equivalent)	0.03 to 0.5 mM/L
pH	6.8 to 8.0
Osmolality	250 to 350 mOsm/kg

Practical reading for freedom-to-operate: staying outside any single numeric range can avoid that claim element. Staying inside all numeric ranges can still be avoided by violating allocation or packaging/mixing requirements, depending on which claim is asserted (Claim 1 vs Claim 15).

Layer 2: solution split constraints (allocation of ions and chemistry)

The claims do not only require the end product composition; they require that:

the basic solution contains bicarbonate ions and is stable/sterile/prepackaged
the acidic solution contains:
- calcium ions
- magnesium ions
- dextrose
- glutathione
chloride can be in at least one solution (and Claim 11 specifies it via NaCl, KCl, CaCl2, MgCl2)

In some dependent claims, sodium and potassium must be in the basic solution specifically (Claims 4 and 5). That is a clean design lever.

Layer 3: process and packaging constraints (Claim 15)

To infringe Claim 15, an accused product would need:

vacuum packaging of the basic solution
a vial with stopper
sterile double-ended needle
vacuum-driven transfer from acidic vial into the basic package
resulting mixed solution within the claim’s numeric envelope

What is the competitive patent “landscape” signal from this claim architecture?

Without adding external prosecution history or citing third-party patents not provided, the landscape can still be characterized by what patent-filing patterns this claim scope implies.

The claims concentrate on a narrow “mixing chemistry” concept

The core inventive structure is a two-part system that:

keeps bicarbonate stable with other nutrients/electrolytes
uses acidic and basic separation to control pH at storage
then yields a mixed irrigating solution with:
- near-neutral to mildly alkaline pH (6.8 to 8.0)
- ionic strengths consistent with the osmolality envelope

This pattern is consistent with broad prior art on sterile irrigation solutions, but the specificity of:

glutathione concentration
bicarbonate range
controlled osmolality
vacuum-driven transfer device (for the article claim)

means the most likely competitive overlap is in later “two-solution” irrigants that optimize:

buffering system (bicarbonate, phosphate)
antioxidant additive (glutathione)
electrolyte matching (Na/K/Ca/Mg targets)
packaging and aseptic transfer method

Risk concentration: numeric overlap is the main infringement lever

If a competitor’s mixed irrigating solution matches the numeric parameters in Claim 1 (or Claim 3) and uses two-part stable prepackaged solutions that satisfy the acid/basic component requirements, Claim 1 exposure is high regardless of whether the competitor uses a different needle or vial device. Claim 15 exposure is narrower because it requires a specific vacuum and double-ended needle transfer architecture.

Main design-around options implied by the claims

A competitor can attempt to avoid:

formulation envelope: change any of Na+, K+, Ca2+, Mg2+, HCO3-, dextrose, glutathione, pH, or osmolality outside the stated ranges
allocation constraints: keep sodium or potassium out of the basic solution if targeting Claims 4 and 5
phosphate variant: omit phosphate or set phosphate outside 1 to 5 mM/L if targeting Claims 2/8/16
device/method: change transfer mechanism away from vacuum-driven double-ended needle (to avoid Claim 15)

How broad are the independent claims compared to the dependent set?

Claim 1 (broadest formulation claim)

Uses “between about” ranges for all key concentrations
Requires only that each of chloride/sodium/potassium be present in at least one solution (not necessarily where)
Focuses primarily on the mixed irrigating solution properties and the acid/basic separation concept

Claim 3 (composition split alternative)

Specifies the component placement more concretely across solutions (basic has bicarbonate + Na + K; acidic has Ca + Mg + dextrose + glutathione)
Still keeps a broad “chloride in at least one solution” requirement

Claim 15 (narrowest, article-of-manufacture with defined mixing)

Adds specific packaging and mixing mechanics
Uses a different Na+ range (103 to 108 mM/L) than Claim 1, which means it is not a simple duplicate and can reduce scope depending on the sodium target used in a competing formulation.

What does the claim set imply about claim enforceability and invalidity attack surface?

The claims are heavily numeric and component-specific. That typically shifts the enforceability question toward whether:

an accused product’s mixed irrigating solution falls within each numeric interval
an accused product satisfies the required presence of bicarbonate in the basic solution and dextrose/glutathione in the acidic solution
an accused product’s buffering system hits the phosphate-dependent subset when asserted

For invalidity, numeric range claims can face prior art challenges when earlier irrigation solutions disclose similar electrolytes and buffering systems with sterile storage and mixing. The unique constraint here is the explicit glutathione concentration range combined with bicarbonate and controlled pH/osmolality in a sterile two-part product. But without importing external prior art patents, the practical “landscape” conclusion is limited to the claim language itself.

Key Takeaways

US 4,550,022 claims a two-part, sterile, prepackaged surgical irrigating solution system where an acidic solution (Ca2+, Mg2+, dextrose, glutathione) and a basic solution (bicarbonate) are mixed to yield a defined electrolyte/solute/pH/osmolality profile.
Claim 1 and Claim 3 target the post-mix formulation envelope (Na 130 to 180 mM/L; pH 6.8 to 8.0; osmolality 250 to 350 mOsm/kg; glutathione 0.03 to 0.5 mM/L; bicarbonate 10 to 50 mM/L), with flexible assignment of chloride/sodium/potassium to at least one solution.
Claims 4 and 5 narrow the allocation of Na+ and K+ specifically to the basic solution.
Claims 2, 8, and 16 add a phosphate (1 to 5 mM/L) sub-scope.
Claims 6, 7, 9, 10, 12, 13 further narrow pH sub-ranges, osmolality sub-range, and basic:acidic volume ratio.
Claim 15 expands into an article-of-manufacture scope requiring vacuum packaging, a rubber-stopper vial, and a sterile double-ended needle that enables vacuum-driven transfer from acidic vial to basic package; it also uses a different Na+ range (103 to 108 mM/L).

FAQs

1) What is the main infringement risk from US 4,550,022 for a competing irrigant?

The highest risk is matching the Claim 1 (or Claim 3) mixed-solution numeric envelope plus the requirement that the product is a two-part sterile prepackaged acid/basic system yielding the claimed pH and osmolality with glutathione and bicarbonate at the specified concentrations.

2) Does Claim 15 require the same sodium range as Claim 1?

No. Claim 1 uses Na+ 130 to 180 mM/L, while Claim 15 uses Na+ 103 to 108 mM/L, even though other component ranges overlap.

3) If a competitor uses different mixing hardware, can it avoid Claim 15?

Claim 15 is tied to vacuum transfer plus a sterile double-ended needle and specific packaging elements. A different mixing architecture can avoid the article-of-manufacture scope, but it does not automatically avoid Claim 1 if the mixed formulation still falls within its ranges.

4) Which claims explicitly require phosphate?

Claims 2, 8, and 16 require phosphate such that the mixed irrigating solution contains 1 to 5 mM/L phosphate ions.

5) Which claims restrict pH at the component (solution) level rather than just the mixed product?

Claim 9 (when phosphate is present) and Claims 12 and 13 (when a specific salt embodiment is present) define basic solution pH 7.2 to 7.8 and acidic solution pH below 5.

References

[1] US Patent No. 4,550,022, “Two-part tissue irrigating product.” Claims as provided in the prompt.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0076658	⤷ Start Trial	SPC/GB93/155 200210	United Kingdom	⤷ Start Trial
Argentina	228986	⤷ Start Trial
Austria	26398	⤷ Start Trial
Australia	559887	⤷ Start Trial
Australia	8853282	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 4,550,022

Summary for Patent: 4,550,022