US Patent 5,457,126 Landscape for Lodoxamide Ocular Allergy Treatment Claims: Scope, Claim Coverage, and US Patent Estate

US Patent 5,457,126 is directed to a topical ophthalmic method for treating ocular allergic responses by applying a therapeutically effective amount of lodoxamide at a specific concentration target (0.1 wt%) using a pharmaceutically acceptable vehicle, with dependent claim recitations covering lodoxamide tromethamine, specific viscosity/buffer/preservative-tonicity systems, and an endpoint of conjunctivitis. The claim scope is narrow in the active ingredient identity and concentration, but practical in that it tolerates “equivalent” salts/esters and a broad “therapeutically effective amount” application regime, leaving meaningful room for formulation variants that still fall within the stated compositional limits.

Core independent claim (Claim 1)

Method-of-use: treat ocular allergic responses in humans.
Administration: topical to the affected eye.
Active: 0.1 wt% lodoxamide or equivalent pharmaceutically acceptable salt or ester.
Vehicle: pharmaceutically acceptable vehicle.

Key dependent claim layers

Claim 2/6: lodoxamide tromethamine.
Claim 3: adds 0.1 to 0.5 wt% hydroxypropyl methyl cellulose (HPMC).
Claim 4/5: buffer pH 3.0 to 7.0, with a preferred system of sodium citrate + citric acid, plus mannitol tonicity, and an ophthalmic preservative.
Claim 7: exemplifies a specific formulation composition (lodoxamide tromethamine plus concrete levels of citrate/citric acid/mannitol/tyloxapol/disodium EDTA/benzalkonium chloride).
Claim 8: topical use to treat conjunctivitis.

Because your request is limited to US Patent 5,457,126 and its provided claims, the landscape below focuses on claim scope mapping and how that scope typically impacts freedom-to-operate for topical lodoxamide ocular allergy products in the US. Patent-by-patent competitive mapping across the entire US estate cannot be completed from the information provided.

What does US Patent 5,457,126 claim protect for ocular allergy treatment?

Claim 1 coverage: method-of-use for topical lodoxamide at 0.1 wt%

Claim 1 protects a specific therapeutic concept:

Treating “ocular allergic responses” in a human patient.
By applying topically to the affected eye.
Using a composition containing 0.1 wt% lodoxamide (or an “equivalent” salt/ester).
In a pharmaceutically acceptable vehicle.
Using a therapeutically effective amount.

Practical interpretation of claim boundaries

The claim is anchored on:
1. Indication: ocular allergic responses (and by dependent claim 8, conjunctivitis).
2. Route: topical ophthalmic application to the eye.
3. Active ingredient identity: lodoxamide or equivalent salt/ester.
4. Active concentration: 0.1 wt% (single-point concentration, not a broad range).
5. Formulation class: vehicle only, without restricting the vehicle identity at the independent level.

What is not explicitly limited in Claim 1

No limitation to:
- specific buffers, viscosity agents, tonicity agents, or preservatives at the independent level.
- specific pH beyond what is only recited in dependent claim 4.
- specific dosing frequency or treatment duration.

Claim 8 extends the indication within the same method claim

Claim 8 narrows within the method-of-use space:

If the topical method is to “treat conjunctivitis,” it is within the patent’s claimed method scope.

Even though conjunctivitis can include multiple etiologies, Claim 8 ties it to the “according to claim 1” structure, so the conjunctivitis treatment is still constrained by the Claim 1 elements (0.1 wt% lodoxamide/salt/ester and topical application for ocular allergic responses).

How narrow is the 0.1 wt% lodoxamide concentration limitation in Claim 1?

Single-point concentration can constrain both formulations and label design

Claim 1 recites a fixed concentration: 0.1 percent by weight lodoxamide (or equivalent salt/ester).

Implications for design-around

Formulations above or below 0.1 wt% are not within Claim 1 as written, unless a doctrine of equivalency is argued (not part of the claim text you provided).
Switching from lodoxamide to a different active falls outside claim by active ingredient.
Using a different concentration is the most direct textual workaround.

Dependent claims introduce only additional excipients, not concentration escape

Claims 2/6 and 3/4/5/7 primarily specify formulation elements; they do not broaden concentration beyond 0.1 wt% in the provided claim text.

Which formulations are explicitly covered: salts, viscosity agents, buffers, tonicity, and preservatives?

Salt/ester scope: “equivalent amount” and lodoxamide tromethamine

Claim 1: lodoxamide or pharmaceutically acceptable salt or ester.
Claim 2 and Claim 6: lodoxamide tromethamine.

Textually, tromethamine is within the “equivalent amount” concept. If you formulate with a different pharmaceutically acceptable salt/ester, Claim 1 could still read on it if “equivalent amount” is met.

Viscosity and thickening: HPMC window

Claim 3 requires: 0.1 to 0.5 wt% hydroxypropyl methyl cellulose.

This does not replace the need for Claim 1’s 0.1 wt% lodoxamide. It is a dependent narrowing limitation, meaning it is only protected if the formulation includes HPMC at that specified range.

pH and buffer system: 3.0 to 7.0

Claim 4 requires buffer to maintain pH 3.0 to 7.0.

This introduces a compositional limitation that can be navigated by changing the buffering system or pH, but still must remain consistent with ocular tolerability. The claim text is a hard window.

Example excipient stack in Claim 5

Claim 5 specifies:

Buffer comprised of sodium citrate and citric acid.
Plus mannitol for tonicity.
Plus an ophthalmically acceptable preservative to maintain sterility.

This is a classic ophthalmic formulation bundle. Any deviation may fall outside Claim 5, but Claim 1 may still be implicated if excipients are changed while keeping lodoxamide at 0.1 wt% and the “vehicle” remains pharmaceutically acceptable.

Explicit “formula” in Claim 7

Claim 7 provides a concrete formulation with multiple excipients at specific levels:

Contains lodoxamide tromethamine.
Additional components include:
- 0.5 wt% sodium citrate
- 0.21 wt% citric acid
- 2.29 wt% mannitol
- 0.025 wt% tyloxapol
- 0.01 wt% disodium EDTA
- 0.01% benzalkonium chloride

This functions as a particularly strong “composition sandwich” within the method-of-use context: it ties the method claim to a specific formulation archetype.

What is the practical claim scope for “conjunctivitis” in Claim 8?

Conjunctivitis is covered only within the Claim 1 constrained composition

Claim 8 says:

“composition is applied topically to the affected eye to treat conjunctivitis,”
and it depends from Claim 1.

So the conjunctivitis treatment is only within the protective scope if:

the composition contains 0.1 wt% lodoxamide (or equivalent salt/ester),
applied topically to the eye,
to treat ocular allergic responses.

If a product’s labeled indication is framed as non-allergic conjunctivitis (or the method evidence does not support “ocular allergic responses”), enforcement would need to match both the method and the allergic-response context.

How strong is the patent estate risk if you sell a topical lodoxamide ocular allergy product in the US?

Claim 1 is a “method wrapper” around a specific concentration and topical route

A generic or branded product that:

uses 0.1 wt% lodoxamide (or the claimed equivalent salt/ester),
is administered topically to the eye,
and is marketed or used for ocular allergic responses (including conjunctivitis under Claim 8), is at higher risk of literal infringement based on Claim 1.

Formulation tweaks may still leave Claim 1 exposure

Because Claim 1 only requires a “pharmaceutically acceptable vehicle,” replacing:

buffer system,
viscosity agent,
tonicity agent,
preservative, does not automatically avoid Claim 1, as long as the active ingredient and concentration remain inside the Claim 1 limits.

But Claim 1 offers a clearer escape at concentration level

A product that uses not 0.1 wt% lodoxamide is more likely to avoid Claim 1 as written. Dependent claims do not override this as a threshold requirement.

What does “therapeutically effective amount” mean for infringement analysis?

It is intentionally broad

Claim 1 does not state:

drops per eye,
dosing interval,
treatment duration,
maximum daily dose.

As a result, “therapeutically effective” is typically treated as met by established clinical use for the claimed indication. For enforcement, evidentiary focus tends to be on product label, instructions for use, prescribing information, and real-world usage consistent with ocular allergic response treatment.

What patent claim variants exist within this single patent: compound-only vs method-only?

This patent is method-of-use centered

The claims provided are all methods of treating ocular allergic responses by topical application of a lodoxamide-containing composition.

If a competing company manufactures a composition that fits the formulation limitations but does not practice the claimed method (no topical treatment of ocular allergic responses), the infringement question shifts heavily toward:

method practice,
inducement/contributory theories in US practice,
and evidence of therapeutic use.

What generic entry risks exist for lodoxamide ocular allergy products under this patent?

High risk if the ANDA matches the 0.1 wt% active and labeled indication

Entry risk rises if:

the product is designed to match 0.1 wt% lodoxamide,
and the proposed labeling indicates treatment of ocular allergic responses (or conjunctivitis in that allergic context).

A labeling carve-out that removes “ocular allergic responses” language may reduce method exposure, but only if the product is not used in the claimed manner. The claim text does not cover a specific labeling form, but real-world practice and marketing can matter.

Lower risk via concentration or indication strategy

Concentration change away from 0.1 wt% is a direct textual non-infringement route.
Indication re-framing away from ocular allergic responses reduces method practice alignment.

Key takeaways

US 5,457,126 Claim 1 protects a topical ophthalmic method for ocular allergic responses using a composition containing exactly 0.1 wt% lodoxamide (or an “equivalent” pharmaceutically acceptable salt/ester) in a pharmaceutically acceptable vehicle.
The patent’s strongest textual anchor is the single-point concentration and topical ocular route combined with ocular allergic response treatment.
Dependent claims add narrower formulation requirements: HPMC (0.1 to 0.5 wt%), buffer pH 3.0 to 7.0, and in particular citrate/citric acid + mannitol + preservative, plus a specific excipient blueprint in Claim 7.
For freedom-to-operate, the most direct claim-avoidance levers from the text are changing lodoxamide concentration away from 0.1 wt% and/or avoiding the claimed allergic-response treatment method.

FAQs

Does US 5,457,126 cover lodoxamide formulations that use a different buffer system than citrate/citric acid?
Claim 1 only requires a pharmaceutically acceptable vehicle; specific citrate/citric acid is only required in dependent Claim 5.
Can a product avoid infringement by using hydroxypropyl methyl cellulose outside 0.1 to 0.5 wt%?
That can avoid dependent Claim 3, but Claim 1 can still be implicated if 0.1 wt% lodoxamide and the claimed method are practiced.
Is conjunctivitis treatment covered even if the product is not described as treating allergic conjunctivitis?
Claim 8 is dependent on Claim 1, so the method still depends on treating “ocular allergic responses” via the claimed lodoxamide composition.
What is the tightest formulation limitation in this patent’s provided claims?
Claim 7 provides a specific excipient composition with fixed weight-percent levels, but Claim 1’s fixed 0.1 wt% lodoxamide is the primary threshold.
Does the patent require a specific dosing regimen?
No dosing frequency or regimen is recited in the provided claim text; it requires a “therapeutically effective amount” applied topically.

References (APA)

US Patent 5,457,126. (Provided claims text).

Title:	Use of lodoxamide to treat ophthalmic allergic conditions
Abstract:	Disclosed are methods of using certain defined phenylene dioxamic acids in treating allergic ocular responses, such as, hayfever, conjunctivitis, atopic and keratoconjunctivitis, vernal conjunctivitis, giant capillary conjunctivitis and other diseases where mast cell degranulation are important in the etiology, by topical administration of said active to the affected eye; also disclosed are pharmaceutical compositions comprising said actives.
Inventor(s):	K. Roger Aoki, Louis M. DeSantis
Assignee:	Alcon Research LLC
Application Number:	US08/215,216
Patent Claim Types: see list of patent claims	Use; Composition;
Patent landscape, scope, and claims:	US Patent 5,457,126 Landscape for Lodoxamide Ocular Allergy Treatment Claims: Scope, Claim Coverage, and US Patent Estate US Patent 5,457,126 is directed to a topical ophthalmic method for treating ocular allergic responses by applying a therapeutically effective amount of lodoxamide at a specific concentration target (0.1 wt%) using a pharmaceutically acceptable vehicle, with dependent claim recitations covering lodoxamide tromethamine, specific viscosity/buffer/preservative-tonicity systems, and an endpoint of conjunctivitis. The claim scope is narrow in the active ingredient identity and concentration, but practical in that it tolerates “equivalent” salts/esters and a broad “therapeutically effective amount” application regime, leaving meaningful room for formulation variants that still fall within the stated compositional limits. Core independent claim (Claim 1) Method-of-use: treat ocular allergic responses in humans. Administration: topical to the affected eye. Active: 0.1 wt% lodoxamide or equivalent pharmaceutically acceptable salt or ester. Vehicle: pharmaceutically acceptable vehicle. Key dependent claim layers Claim 2/6: lodoxamide tromethamine. Claim 3: adds 0.1 to 0.5 wt% hydroxypropyl methyl cellulose (HPMC). Claim 4/5: buffer pH 3.0 to 7.0, with a preferred system of sodium citrate + citric acid, plus mannitol tonicity, and an ophthalmic preservative. Claim 7: exemplifies a specific formulation composition (lodoxamide tromethamine plus concrete levels of citrate/citric acid/mannitol/tyloxapol/disodium EDTA/benzalkonium chloride). Claim 8: topical use to treat conjunctivitis. Because your request is limited to US Patent 5,457,126 and its provided claims, the landscape below focuses on claim scope mapping and how that scope typically impacts freedom-to-operate for topical lodoxamide ocular allergy products in the US. Patent-by-patent competitive mapping across the entire US estate cannot be completed from the information provided. What does US Patent 5,457,126 claim protect for ocular allergy treatment? Claim 1 coverage: method-of-use for topical lodoxamide at 0.1 wt% Claim 1 protects a specific therapeutic concept: Treating “ocular allergic responses” in a human patient. By applying topically to the affected eye. Using a composition containing 0.1 wt% lodoxamide (or an “equivalent” salt/ester). In a pharmaceutically acceptable vehicle. Using a therapeutically effective amount. Practical interpretation of claim boundaries The claim is anchored on: Indication: ocular allergic responses (and by dependent claim 8, conjunctivitis). Route: topical ophthalmic application to the eye. Active ingredient identity: lodoxamide or equivalent salt/ester. Active concentration: 0.1 wt% (single-point concentration, not a broad range). Formulation class: vehicle only, without restricting the vehicle identity at the independent level. What is not explicitly limited in Claim 1 No limitation to: specific buffers, viscosity agents, tonicity agents, or preservatives at the independent level. specific pH beyond what is only recited in dependent claim 4. specific dosing frequency or treatment duration. Claim 8 extends the indication within the same method claim Claim 8 narrows within the method-of-use space: If the topical method is to “treat conjunctivitis,” it is within the patent’s claimed method scope. Even though conjunctivitis can include multiple etiologies, Claim 8 ties it to the “according to claim 1” structure, so the conjunctivitis treatment is still constrained by the Claim 1 elements (0.1 wt% lodoxamide/salt/ester and topical application for ocular allergic responses). How narrow is the 0.1 wt% lodoxamide concentration limitation in Claim 1? Single-point concentration can constrain both formulations and label design Claim 1 recites a fixed concentration: 0.1 percent by weight lodoxamide (or equivalent salt/ester). Implications for design-around Formulations above or below 0.1 wt% are not within Claim 1 as written, unless a doctrine of equivalency is argued (not part of the claim text you provided). Switching from lodoxamide to a different active falls outside claim by active ingredient. Using a different concentration is the most direct textual workaround. Dependent claims introduce only additional excipients, not concentration escape Claims 2/6 and 3/4/5/7 primarily specify formulation elements; they do not broaden concentration beyond 0.1 wt% in the provided claim text. Which formulations are explicitly covered: salts, viscosity agents, buffers, tonicity, and preservatives? Salt/ester scope: “equivalent amount” and lodoxamide tromethamine Claim 1: lodoxamide or pharmaceutically acceptable salt or ester. Claim 2 and Claim 6: lodoxamide tromethamine. Textually, tromethamine is within the “equivalent amount” concept. If you formulate with a different pharmaceutically acceptable salt/ester, Claim 1 could still read on it if “equivalent amount” is met. Viscosity and thickening: HPMC window Claim 3 requires: 0.1 to 0.5 wt% hydroxypropyl methyl cellulose. This does not replace the need for Claim 1’s 0.1 wt% lodoxamide. It is a dependent narrowing limitation, meaning it is only protected if the formulation includes HPMC at that specified range. pH and buffer system: 3.0 to 7.0 Claim 4 requires buffer to maintain pH 3.0 to 7.0. This introduces a compositional limitation that can be navigated by changing the buffering system or pH, but still must remain consistent with ocular tolerability. The claim text is a hard window. Example excipient stack in Claim 5 Claim 5 specifies: Buffer comprised of sodium citrate and citric acid. Plus mannitol for tonicity. Plus an ophthalmically acceptable preservative to maintain sterility. This is a classic ophthalmic formulation bundle. Any deviation may fall outside Claim 5, but Claim 1 may still be implicated if excipients are changed while keeping lodoxamide at 0.1 wt% and the “vehicle” remains pharmaceutically acceptable. Explicit “formula” in Claim 7 Claim 7 provides a concrete formulation with multiple excipients at specific levels: Contains lodoxamide tromethamine. Additional components include: 0.5 wt% sodium citrate 0.21 wt% citric acid 2.29 wt% mannitol 0.025 wt% tyloxapol 0.01 wt% disodium EDTA 0.01% benzalkonium chloride This functions as a particularly strong “composition sandwich” within the method-of-use context: it ties the method claim to a specific formulation archetype. What is the practical claim scope for “conjunctivitis” in Claim 8? Conjunctivitis is covered only within the Claim 1 constrained composition Claim 8 says: “composition is applied topically to the affected eye to treat conjunctivitis,” and it depends from Claim 1. So the conjunctivitis treatment is only within the protective scope if: the composition contains 0.1 wt% lodoxamide (or equivalent salt/ester), applied topically to the eye, to treat ocular allergic responses. If a product’s labeled indication is framed as non-allergic conjunctivitis (or the method evidence does not support “ocular allergic responses”), enforcement would need to match both the method and the allergic-response context. How strong is the patent estate risk if you sell a topical lodoxamide ocular allergy product in the US? Claim 1 is a “method wrapper” around a specific concentration and topical route A generic or branded product that: uses 0.1 wt% lodoxamide (or the claimed equivalent salt/ester), is administered topically to the eye, and is marketed or used for ocular allergic responses (including conjunctivitis under Claim 8), is at higher risk of literal infringement based on Claim 1. Formulation tweaks may still leave Claim 1 exposure Because Claim 1 only requires a “pharmaceutically acceptable vehicle,” replacing: buffer system, viscosity agent, tonicity agent, preservative, does not automatically avoid Claim 1, as long as the active ingredient and concentration remain inside the Claim 1 limits. But Claim 1 offers a clearer escape at concentration level A product that uses not 0.1 wt% lodoxamide is more likely to avoid Claim 1 as written. Dependent claims do not override this as a threshold requirement. What does “therapeutically effective amount” mean for infringement analysis? It is intentionally broad Claim 1 does not state: drops per eye, dosing interval, treatment duration, maximum daily dose. As a result, “therapeutically effective” is typically treated as met by established clinical use for the claimed indication. For enforcement, evidentiary focus tends to be on product label, instructions for use, prescribing information, and real-world usage consistent with ocular allergic response treatment. What patent claim variants exist within this single patent: compound-only vs method-only? This patent is method-of-use centered The claims provided are all methods of treating ocular allergic responses by topical application of a lodoxamide-containing composition. If a competing company manufactures a composition that fits the formulation limitations but does not practice the claimed method (no topical treatment of ocular allergic responses), the infringement question shifts heavily toward: method practice, inducement/contributory theories in US practice, and evidence of therapeutic use. What generic entry risks exist for lodoxamide ocular allergy products under this patent? High risk if the ANDA matches the 0.1 wt% active and labeled indication Entry risk rises if: the product is designed to match 0.1 wt% lodoxamide, and the proposed labeling indicates treatment of ocular allergic responses (or conjunctivitis in that allergic context). A labeling carve-out that removes “ocular allergic responses” language may reduce method exposure, but only if the product is not used in the claimed manner. The claim text does not cover a specific labeling form, but real-world practice and marketing can matter. Lower risk via concentration or indication strategy Concentration change away from 0.1 wt% is a direct textual non-infringement route. Indication re-framing away from ocular allergic responses reduces method practice alignment. Key takeaways US 5,457,126 Claim 1 protects a topical ophthalmic method for ocular allergic responses using a composition containing exactly 0.1 wt% lodoxamide (or an “equivalent” pharmaceutically acceptable salt/ester) in a pharmaceutically acceptable vehicle. The patent’s strongest textual anchor is the single-point concentration and topical ocular route combined with ocular allergic response treatment. Dependent claims add narrower formulation requirements: HPMC (0.1 to 0.5 wt%), buffer pH 3.0 to 7.0, and in particular citrate/citric acid + mannitol + preservative, plus a specific excipient blueprint in Claim 7. For freedom-to-operate, the most direct claim-avoidance levers from the text are changing lodoxamide concentration away from 0.1 wt% and/or avoiding the claimed allergic-response treatment method. FAQs Does US 5,457,126 cover lodoxamide formulations that use a different buffer system than citrate/citric acid? Claim 1 only requires a pharmaceutically acceptable vehicle; specific citrate/citric acid is only required in dependent Claim 5. Can a product avoid infringement by using hydroxypropyl methyl cellulose outside 0.1 to 0.5 wt%? That can avoid dependent Claim 3, but Claim 1 can still be implicated if 0.1 wt% lodoxamide and the claimed method are practiced. Is conjunctivitis treatment covered even if the product is not described as treating allergic conjunctivitis? Claim 8 is dependent on Claim 1, so the method still depends on treating “ocular allergic responses” via the claimed lodoxamide composition. What is the tightest formulation limitation in this patent’s provided claims? Claim 7 provides a specific excipient composition with fixed weight-percent levels, but Claim 1’s fixed 0.1 wt% lodoxamide is the primary threshold. Does the patent require a specific dosing regimen? No dosing frequency or regimen is recited in the provided claim text; it requires a “therapeutically effective amount” applied topically. References (APA) US Patent 5,457,126. (Provided claims text). More… ↓ ⤷ Start Trial

Details for Patent: 5,457,126

Summary for Patent: 5,457,126