Patent 5,474,979 Landscape: Scope and Claim Coverage for Nonirritating Cyclosporine Ocular Emulsions (Pemulen + Polysorbate 80 + Glycerides)

United States Patent US 5,474,979 covers topical ocular emulsion compositions in which cyclosporin (including cyclosporin A) is maintained in a nonirritating emulsion by combining (i) a higher fatty acid glyceride (notably castor oil), (ii) polysorbate 80, and (iii) Pemulen (a carbomer/alkyl acrylate copolymer, used as a polymeric emulsifier/thickener), in water for ocular tissue application. The claim core is twofold: (1) a specific composition architecture (cyclosporin + higher fatty acid glyceride + polysorbate 80 + Pemulen + water) and (2) an anti-crystallization performance window stated as preventing cyclosporin crystallization for up to about nine months. The strongest literal claim coverage is for formulations within the tight quantitative ranges for cyclosporin A, castor oil, polysorbate 80, Pemulen, and glycerine and within a target ocular pH window.

How broad are US 5,474,979 claims for cyclosporin ocular emulsions?

Short answer: The independent claim (claim 1) is composition-defined and fairly broad on component identity (higher fatty acid glyceride) and broader on cyclosporin identity (any cyclosporin), but it narrows materially in dependent claims by (i) requiring cyclosporin A, (ii) imposing glyceride:polysorbate 80 ratio boundaries, (iii) specifying castor oil as the glyceride in a specific ratio to cyclosporin A, and (iv) requiring a performance outcome (no cyclosporin crystallization for up to ~9 months). Claim 6 and claim 8 further lock down an emulsion “recipe” including glycerine and a pH range.

Claim-by-claim scope mapping

Claim 1 (independent): Nonirritating ocular emulsion architecture

Text scope elements

Dosage form: “pharmaceutical composition” as an “emulsion”
Actives: “at least one cyclosporin”
Stabilizing components:
- “higher fatty acid glyceride”
- “polysorbate 80”
- “an emulsion stabilizing amount of Pemulen”
Vehicle: “in water”
Route: “suitable for topical application to ocular tissue”
Functional/quality attribute: “nonirritating” emulsion

Breadth

Component breadth: “higher fatty acid glyceride” is open-ended (not limited to castor oil in claim 1).
Cyclosporin breadth: covers “at least one cyclosporin,” so it reaches cyclosporin mixtures if used.
Performance attribute: “nonirritating” is asserted but not quantified in claim 1; it operates more as a characteristic than a measurable parameter unless tied to prosecution history.

Practical inference for claim 1 A formulation that contains all four elements (cyclosporin + glyceride + polysorbate 80 + Pemulen in water) and is presented for ocular topical use is a direct candidate for literal infringement, even if the glyceride identity differs from castor oil, unless the accused product avoids one element or moves away from an “emulsion” characterization.

Claim 2: Cyclosporin identity narrows to cyclosporin A

Claim 2 makes explicit coverage for “wherein the cyclosporin comprises cyclosporin A.” This becomes important when competitors switch to other cyclosporin species or derivatives.

Claim 3: Ratio window (higher fatty acid glyceride : polysorbate 80)

“weight ratio of the higher fatty acid glyceride to the polysorbate 80 is between about 0.3 and about 30”

This is a meaningful narrowing because it can be engineered around by shifting relative amounts. Claim 3 applies regardless of whether glyceride is castor oil or another glyceride, since “higher fatty acid glyceride” remains generic here.

Claim 4: Castor oil and cyclosporin:castor oil limit

Higher fatty acid glyceride comprises “castor oil”
“weight ratio of cyclosporin to castor oil is below about 0.16”

This creates two literal levers:

Use of non-castor glycerides may escape claim 4 while still falling under claim 1 or 3.
Even with castor oil, shifting cyclosporin concentration relative to castor oil above the threshold could avoid literal claim 4 (though it might still infringe claim 1/3).

Claim 5: Anti-crystallization outcome up to nine months

“higher fatty acid glyceride and polysorbate 80 are present in amounts sufficient to prevent crystallization of cyclosporin for up to about nine months”

This is both a scope-expander and a litigation pressure point. It links component selection to a performance result. For infringement, the patentee can argue that an accused formulation inherently or in tests meets the anti-crystallization period. For a defense, the manufacturer can argue non-equivalency if the formulation crystallizes earlier or uses alternate stabilization mechanisms that do not meet the specified outcome “up to about nine months.”

Claim 6: Specific emulsion recipe including glycerine (and nine-month stability)

Claim 6 recasts the invention as a “pharmaceutical emulsion comprising”:

cyclosporin A
castor oil
Pemulen
glycerine
polysorbate 80
water
paves the same performance attribute: prevents crystallization “for up to about nine months”
route: ocular topical

Claim 6 is more specific than claim 1 and is likely closer to marketed composition patterns because it explicitly includes glycerine.

Claim 7: Specific quantitative ranges (a highly actionable literal infringement map)

Claim 7 provides numeric ranges (or nominal values) for:

Cyclosporin A: 0.05% to 0.40%
Castor oil: 0.625% to 5.0%
Polysorbate 80: about 1.0%
Pemulen: about 0.05%
Glycerine: about 2.2%

These are directly usable for “design-around” analysis. If a competitor uses different polysorbate level, Pemulen level, glycerine level, or cyclosporin and castor oil outside the windows, literal infringement of claim 7 is less likely. Claim 7 is less helpful for those outside the exact combination values but still may contribute to doctrine-of-equivalents arguments.

Claim 8: “Consisting of” plus explicit pH window

Claim 8 states:

“pharmaceutical emulsion consisting of” the listed components
concentrations fixed to narrower terms (ranges for cyclosporin A and castor oil; nominal values for polysorbate 80, Pemulen, glycerine)
pH between 7.2 and 7.6
ocular topical suitability

Key legal consequence of “consisting of” “Consisting of” generally excludes additional ingredients beyond those listed, unless an excluded item is legally characterized as immaterial or does not add materially to composition. This makes claim 8 stronger for clean-room and more vulnerable to formulation changes that introduce other excipients (buffering agents, preservatives, tonicity agents, salts) that would be “additional ingredients” under claim construction.

What formulations are protected by US 5,474,979 (active, excipients, ratios, pH)?

Core protected formulation class

Active: cyclosporin, especially cyclosporin A
Vehicle system: water-based emulsion with
- higher fatty acid glyceride (castor oil favored in dependent claims)
- polysorbate 80
- Pemulen
- optional in broader claims, explicit in claim 6+: glycerine
Performance: prevents cyclosporin crystallization for up to ~9 months
Route: ocular topical tissue

Quantitative claim anchors (most infringement-relevant)

Claim	Cyclosporin A (wt%)	Castor oil (wt%)	Polysorbate 80 (wt%)	Pemulen (wt%)	Glycerine (wt%)	Ratio constraints	pH
3	not limited	not limited	not limited	not limited	not limited	glyceride:polysorbate 80 = 0.3 to 30	not specified
4	implied	implied	implied	implied	implied	cyclosporin:castor oil <0.16	not specified
5	implied	required	required	not specified	not specified	anti-crystallization up to ~9 months	not specified
6	uses cyclosporin A	requires castor oil	requires polysorbate 80	requires Pemulen	requires glycerine	anti-crystallization up to ~9 months	not specified
7	0.05 to 0.40	0.625 to 5.0	~1.0	~0.05	~2.2	none additional	not specified
8	0.05 to 0.40	0.625 to 5.0	~1.0	~0.05	~2.2	consists of listed components; pH limited	7.2 to 7.6

When does US 5,474,979 lose exclusivity for cyclosporin topical ocular products?

No exclusivity or expiration timeline can be computed from the claim text alone. A complete exclusivity and term analysis requires at minimum:

filing date, nonprovisional claim priority, and patent grant date
any PTA (patent term adjustment)
any terminal disclaimer
whether the patent is listed for particular Orange Book/NDA/ANDA products and whether pediatric exclusivity or other extensions apply

Because those inputs are not present in the provided material, a correct expiration date cannot be produced here.

What patent litigation risks does US 5,474,979 create for generic or reformulated cyclosporin emulsions?

A litigation risk assessment requires docket-level sources (parties, asserted claims, jurisdictions, case numbers, and outcomes). The provided content includes only the claim language, not:

which products were accused
whether any Paragraph IV notices asserted this patent
whether settlements imposed launch or design-around commitments

Without those records, an accurate litigation-risk map cannot be generated.

How strong is the patent estate for Pemulen-polysorbate ocular cyclosporin emulsions around US 5,474,979?

A “strength” assessment also depends on external data: prosecution history (claim scope concessions), examiner rejections (prior art), and whether the patent is part of a family with continuations that broaden or narrow the claim strategy. None of that is included in the provided input.

What can be evaluated purely from the claims:

Strength of coverage: high against a formulation that matches the architecture and performance attribute (especially for claim 6, 7, 8).
Attack surface: the “consisting of” language in claim 8 can be used as an off-ramp if competitors add buffers/preservatives that fall outside the claim list.
Performance attribute: “prevent crystallization … up to about nine months” can be a point of evidentiary dispute (test design, stability protocols, and whether crystallization is observed under comparable storage conditions).

Are there design-around strategies that avoid claim 1 while keeping cyclosporin ocular emulsions?

Based on the claim structure alone, infringement avoidance typically targets at least one of the required elements:

Element-switching levers

Remove or replace Pemulen (claim 1 requires “emulsion stabilizing amount of Pemulen”).
Remove polysorbate 80 (claim 1 requires polysorbate 80).
Avoid “emulsion” characterization by changing to another dosage architecture not meeting the emulsion definition (high-stakes claim construction).
Change to a different stabilization system while maintaining ocular tolerability, though claim 1 requires the presence of the specific combination in water.

Ratio levers in dependent claims

Adjust glyceride:polysorbate 80 outside 0.3 to 30 (claim 3).
Use castor oil but change cyclosporin:castor oil above 0.16 (claim 4).
Adjust cyclosporin/castor oil ranges or keep polysorbate/Pemulen/glycerine away from the values in claim 7.

“Consisting of” lever

For claim 8, introduce additional excipients such that the formulation is no longer within the “consisting of” list (subject to materiality and claim construction).

These are structural levers grounded in the literal claim requirements; actual infringement outcomes depend on claim construction and the accused formulation’s specific composition.

How many other patents likely cover Pemulen + polysorbate 80 + cyclosporin emulsions in ocular tissue?

A quantified “how many patents” answer requires a patent landscape search across:

US and PCT family members
related ocular cyclosporin formulation families
assignees and cited references
keyword and CPC class searches for cyclosporin emulsions and Pemulen polymers

No search results or family metadata are provided, so an evidence-backed count cannot be produced.

Orange Book status: what is the regulatory listing impact of US 5,474,979 for cyclosporin?

Orange Book status is product-specific and requires:

NDA/ANDA association
listed patents (including formulation patents)
expiration or delisting triggers

None of this is included in the provided input, so regulatory status cannot be stated accurately.

Commercial implications: what revenue is most exposed if US 5,474,979 is asserted?

Revenue exposure requires:

which marketed products are covered by this patent via Orange Book listing or other regulatory ties
US sales attribution by product and dosage form
timing relative to patent expiration and potential generic entry

The provided material does not include these commercial facts; no revenue exposure calculation can be responsibly generated.

Key Takeaways

US 5,474,979 protects a water-based ocular topical emulsion of cyclosporin (especially cyclosporin A) stabilized using the specific combination of higher fatty acid glyceride (castor oil in narrower claims), polysorbate 80, and Pemulen.
The most infringement-sensitive language combines:
- anti-crystallization performance: prevents cyclosporin crystallization for up to ~9 months (claim 5/6)
- tight formulation ranges (claim 7) and pH lock (claim 8: 7.2 to 7.6)
- “consisting of” component limitation in claim 8, which can be a key design-around boundary.
The primary claim 1 is broad on cyclosporin identity (“at least one cyclosporin”) and glyceride identity, but it still requires all three excipient classes (glyceride + polysorbate 80 + Pemulen) in water for ocular topical use.

FAQs

1) What exact components are required for literal infringement of claim 1 of US 5,474,979?
Cyclopsorin (at least one), higher fatty acid glyceride, polysorbate 80, and Pemulen in water for topical ocular use.

2) What does the “up to about nine months” crystallization language mean for a cyclosporin emulsion stability profile?
It ties the glyceride and polysorbate 80 presence to an anti-crystallization outcome for a specified time window (claims 5 and 6).

3) How does claim 8’s “consisting of” wording affect reformulations?
It limits the emulsion to the listed components, making additional excipients a potential literal avoidance route.

4) What composition levers most directly control whether claim 7 is met?
Cyclosporin A concentration, castor oil concentration, and maintaining polysorbate 80, Pemulen, and glycerine near the specified nominal amounts.

5) Which dependent claim narrows US 5,474,979 to cyclosporin A specifically?
Claim 2 (and claim 6) requires cyclosporin A.

References (APA)

No external sources were provided or cited in the prompt.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
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Details for Patent: 5,474,979

Summary for Patent: 5,474,979