United States Patent 10,596,107: Claim Scope, Lotemax SM Relevance, and Ophthalmic Suspension Patent Landscape

U.S. Patent No. 10,596,107 protects ophthalmic suspensions that combine tightly controlled active-ingredient particle size with a vehicle containing a carboxyvinyl polymer and a nonionic cellulose derivative. The dependent claims narrow the protection toward polycarbophil, hydroxypropyl methylcellulose E4M, poloxamer 407, loteprednol or loteprednol etabonate, and a 0.38 wt% loteprednol etabonate formulation. The claim set is technically aligned with the formulation architecture used in Lotemax SM, the 0.38% loteprednol etabonate ophthalmic gel suspension marketed by Bausch + Lomb.

The strongest commercial claims are claims 8, 10, 13 and 17. They combine particle-size limits with a defined excipient system and, in claim 10, a specific active concentration. A generic product that uses the same formulation architecture and particle-size distribution could face both literal-infringement and Paragraph IV certification risk.

What does U.S. Patent 10,596,107 protect?

The patent has two principal protection categories:

Composition claims covering ophthalmic suspensions.
Method-of-treatment claims covering administration of those suspensions for ophthalmic inflammation.

Claim 1 is the central composition claim. It requires every one of the following elements:

Claim 1 limitation	Required feature
Dosage form	Ophthalmic suspension
Active ingredient	Ophthalmic active ingredient
Physical state	Active ingredient suspended as particles
Particle size	Dv90 less than 5 µm and Dv50 less than 1 µm
Vehicle	Formulation vehicle
Rheology agent	Suspending agent
Suspending polymer	Carboxyvinyl polymer
Cellulosic polymer	Nonionic cellulose derivative

The claim is not limited to loteprednol. On its face, it covers any ophthalmic active ingredient satisfying the particle-size and vehicle requirements. Loteprednol becomes a limitation only in claims 9, 10 and 13.

The particle-size limitations are central. Dv50 is the volume-weighted median particle diameter. Dv90 is the diameter below which 90% of the measured particle volume falls. A product with Dv90 of 5 µm or greater would not satisfy the literal Dv90 limitation in claim 1, even if its Dv50 were below 1 µm.

How narrow are the independent claims?

Composition claim 1

Claim 1 is broad in active ingredient and excipient identity but narrow in formulation structure. A competing product must avoid at least one required limitation to escape literal infringement.

Potential design-around routes include:

Using a suspending agent that is not a carboxyvinyl polymer.
Omitting the nonionic cellulose derivative.
Using particles with Dv90 of 5 µm or greater.
Using a Dv50 of 1 µm or greater.
Formulating the active ingredient as a solution, emulsion, nanosuspension with a materially different vehicle, or another dosage form rather than the claimed suspension.

The practical strength of the claim depends on how the patent specification defines “carboxyvinyl polymer,” “nonionic cellulose derivative,” “suspension,” and the particle-size measurement method. Those construction issues could materially affect infringement analysis.

Method claim 14

Claim 14 requires administration of a suspension meeting claim 1 to treat an ophthalmic inflammatory condition. It is narrower than claim 1 because it requires an act of treatment and a disease context.

Claims 15 through 17 add administration frequency, disease indication and excipient restrictions. Claim 16 covers inflammation resulting from post-ocular surgery or uveitis. Claim 17 specifies a vehicle containing polycarbophil, hydroxypropyl methylcellulose, benzalkonium chloride, a nonionic surfactant, glycerin, propylene glycol and a borate buffer.

Method claims may be relevant to branded-product labeling and induced-infringement theories. They are less useful against an abbreviated new drug application applicant if the proposed labeling omits the patented indication or dosing regimen, although the commercial facts and FDA-approved labeling would control the analysis.

What do claims 2 through 13 add?

Claim	Added limitation	Commercial or technical significance
2	Storage stable for at least two years	Adds a stability-performance limitation; likely requires evidence from shelf-life data
3	Carboxyvinyl polymer is polycarbophil	Narrows the polymer identity
4	Cellulose derivative is hydroxypropyl methylcellulose	Narrows the cellulose polymer
5	Hydroxypropyl methylcellulose is HPMC E4M	Identifies a specific viscosity grade
6	Vehicle contains a surfactant	Adds wetting or dispersion functionality
7	Surfactant comprises poloxamer 407	Narrows the surfactant
8	Polycarbophil, HPMC, poloxamer, glycerin, propylene glycol and borate buffer	Captures a defined multi-excipient vehicle
9	Loteprednol at 0.1% to 0.4%	Covers a concentration range
10	Loteprednol etabonate at 0.38%	Closely tracks Lotemax SM
11	Dv90 below 3 µm and Dv50 below 1 µm	Tighter particle-size requirement
12	Dv90 below 3 µm and Dv50 below 0.6 µm	Tightest expressly claimed particle-size range
13	Loteprednol, polycarbophil and HPMC concentration ranges	Combines active and polymer ranges
14	Treatment of an ophthalmic inflammatory condition	Method-of-use protection
15	Administration once or twice daily	Dosing-frequency limitation
16	Post-ocular-surgery inflammation or uveitis	Indication limitation
17	Specific vehicle with benzalkonium chloride and nonionic surfactant	Expanded vehicle combination for method claims

Claims 11 and 12 are especially important in a formulation comparison. A product may fall outside the broad particle-size threshold in claim 1 while still being tested against the narrower claims if it has Dv90 below 3 µm and Dv50 below 1 µm or 0.6 µm.

What product is most closely associated with the patent?

The claims closely correspond to the formulation profile of Lotemax SM, an ophthalmic gel suspension containing loteprednol etabonate 0.38%. The FDA-approved product is used for postoperative ocular inflammation and pain. Its label identifies loteprednol etabonate as the active ingredient and includes excipients associated with the claimed vehicle architecture, including polymers, surfactant, polyols and buffering components.[2]

The relationship between the patent and Lotemax SM should be evaluated claim by claim rather than by brand identity alone. Product labeling generally does not disclose particle-size distributions such as Dv50 and Dv90. Those values would typically be established through regulatory submissions, confidential technical documentation, discovery, or analytical testing.

Product	Active ingredient	Strength	Formulation type	Relevance to U.S. 10,596,107
Lotemax SM	Loteprednol etabonate	0.38%	Ophthalmic gel suspension	Closest apparent commercial product
Lotemax	Loteprednol etabonate	0.5%	Ophthalmic suspension or gel, depending on product	May implicate broader composition claims depending on vehicle and particle size
Inveltys	Loteprednol etabonate	1%	Ophthalmic suspension	Competing loteprednol product; concentration falls outside claims 9, 10 and 13 but may be relevant to claim 1
Eysuvis	Loteprednol etabonate	0.25%	Ophthalmic suspension	Falls within claim 9’s stated concentration range; separate formulation and patent analysis required
Generic loteprednol products	Loteprednol etabonate	Commonly 0.5%	Ophthalmic suspension or gel	Risk depends on formulation composition and particle size

The presence of loteprednol etabonate alone does not establish infringement. A product must also satisfy the applicable vehicle and particle-size limitations.

What patent landscape covers loteprednol ophthalmic products?

The relevant landscape contains several overlapping patent categories:

Active-ingredient and chemical patents

Loteprednol etabonate is an esterified corticosteroid developed for topical ophthalmic use. Basic compound and composition-of-matter patents are generally older than the formulation patents protecting later commercial products. For current generic-entry analysis, the remaining barriers are more likely to involve formulation, delivery, manufacturing and method-of-use patents than the original chemical patent.

Formulation patents

Formulation patents cover:

Particle-size reduction.
Suspension stability.
Polymer combinations.
Gel-forming vehicles.
Surfactant systems.
Preservative and buffer combinations.
Reduced dosing frequency.
Improved ocular residence time.
Reduced shaking or settling requirements.

U.S. Patent 10,596,107 is primarily a formulation patent. Its commercially important contribution is the combination of micronized or finely dispersed active particles with polycarbophil and a nonionic cellulose derivative.

Method-of-use patents

Method claims in this area may cover:

Treatment of postoperative inflammation.
Treatment of uveitis.
Once-daily or twice-daily dosing.
Short treatment courses.
Reduced exposure to corticosteroid-related adverse effects.
Use in patients with particular ocular conditions.

Claims 14 through 17 are the method-of-use component of U.S. 10,596,107. Their enforceability against a generic depends heavily on the approved label, the proposed ANDA labeling and the evidence of intended use.

Manufacturing and process patents

Manufacturing barriers may include:

Wet milling or particle-size reduction.
Control of crystal form and polymorphism.
Incorporation of poorly soluble corticosteroids into a stable suspension.
Uniform distribution of high-viscosity polymers.
Sterile processing and aseptic filling.
Control of aggregation during storage.
Reproducible measurement of Dv50 and Dv90.

A generic applicant can avoid a process patent by using a different manufacturing route, but process equivalence and product-by-process evidence may still become relevant in litigation.

What is the Orange Book status of U.S. Patent 10,596,107?

The Orange Book is the primary FDA source for patents submitted by NDA sponsors for approved small-molecule drug products.[1] The relevant question is not simply whether U.S. Patent 10,596,107 exists. The analysis requires determining:

Whether the patent is listed against Lotemax SM or another NDA.
Which NDA and product strength are identified.
Whether the listing covers the drug substance, drug product or method of use.
The listed patent expiration date.
Whether pediatric exclusivity or patent-term adjustment changes the effective date.
Whether the patent has been delisted, challenged or amended.

The patent’s claims are product and method claims rather than pure compound claims. That makes drug-product and method-of-use listing more likely than active-ingredient listing, subject to FDA’s statutory listing standards.

An Orange Book listing would create a formal ANDA certification issue. A Paragraph IV certification would require the generic applicant to assert that the patent is invalid, unenforceable or will not be infringed. A Paragraph III certification would defer approval until patent expiry.

When does U.S. Patent 10,596,107 lose exclusivity?

The patent expiration date cannot be derived from the patent number or issue date alone. The operative date depends on the earliest effective nonprovisional filing date in the priority chain, terminal disclaimers, patent-term adjustment and any applicable pediatric extension. The controlling expiration date should be taken from the current USPTO patent record and the FDA Orange Book listing for the relevant product.[1,3]

A key legal point is that continuation patents generally retain the term of the parent application. The 2020 issue date therefore does not mean that the patent receives a new 20-year term beginning in 2020.

Any commercial exclusivity associated with the product is separate from patent exclusivity. FDA New Chemical Entity exclusivity, three-year clinical-investigation exclusivity, orphan exclusivity and pediatric exclusivity operate under different rules. Lotemax SM’s approval date and any regulatory exclusivity must be evaluated independently from the patent term.[2]

What Paragraph IV challenges and generic-entry risks exist?

A generic applicant targeting a product covered by this patent could pursue several strategies.

Noninfringement strategy

The applicant could formulate a product with:

Dv90 at or above 5 µm.
Dv50 at or above 1 µm.
A different suspending polymer.
No nonionic cellulose derivative.
A vehicle that uses a different viscosity system.
A different surfactant or no surfactant.
A concentration outside the loteprednol ranges in claims 9 and 13.

This strategy is strongest if the alternative formulation remains pharmaceutically equivalent and does not meet the broad limitations of claim 1.

Invalidity strategy

Potential validity challenges could focus on:

Anticipation by earlier ophthalmic suspension formulations.
Obviousness based on known use of polycarbophil and HPMC.
Obviousness of particle-size reduction for poorly soluble corticosteroids.
Written-description support for the full breadth of “ophthalmic active ingredient.”
Enablement across all active ingredients and all claimed excipient combinations.
Indefiniteness or measurement ambiguity involving Dv50 and Dv90.
Adequacy of support for the two-year storage-stability limitation.

The strongest validity case would require prior art disclosing the claimed particle-size distribution together with both a carboxyvinyl polymer and a nonionic cellulose derivative.

Formulation substitution strategy

A generic could avoid the narrower claims by using carbomer rather than polycarbophil, or hydroxyethyl cellulose, methylcellulose or another polymer rather than HPMC. The outcome would depend on whether the selected material falls within the patent’s construction of “carboxyvinyl polymer” or “nonionic cellulose derivative.”

How strong is the patent estate?

The patent has moderate-to-strong formulation protection for products that reproduce the claimed architecture. Its strength is highest where the accused product has all of the following:

Loteprednol etabonate.
A concentration near 0.38%.
Submicron median particle size.
Dv90 below 3 or 5 µm.
Polycarbophil.
HPMC, particularly HPMC E4M.
Poloxamer 407.
Glycerin, propylene glycol and borate buffer.

The estate is weaker against products that use a different rheology platform or particle-size profile. Claim 1 is broad enough to create screening risk for other ophthalmic actives, but the narrower loteprednol claims provide the clearest commercial linkage to Lotemax SM.

The two-year stability limitation in claim 2 is less useful as a stand-alone blocking claim because stability may be difficult to establish from public product information. It can become important in discovery if the branded product’s long-term stability data directly demonstrate the limitation.

What litigation and settlement issues matter?

A complete freedom-to-operate review should examine:

ANDA litigation under the Hatch-Waxman Act.
Declaratory-judgment actions involving the patent.
Paragraph IV notice letters.
Consent judgments and settlement agreements.
Patent-term disclaimers.
Orange Book corrections or delistings.
Any covenant not to sue granted to a generic applicant.
Licensing arrangements involving Bausch + Lomb or other product rights holders.

No settlement conclusion should be inferred from the patent’s existence or from the commercial availability of generic loteprednol products. Generic products may use different strengths, formulations, sponsors, labeling or patent certifications.

How does U.S. Patent 10,596,107 compare with competing product protection?

Issue	U.S. 10,596,107	Generic loteprednol risk	Eysuvis and Inveltys landscape
Core protection	Particle size plus polymer vehicle	Depends on exact formulation	Each product has its own formulation estate
Loteprednol concentration	Claims 9 and 13 cover 0.1% to 0.4%; claim 10 targets 0.38%	0.5% products may avoid these narrower claims	Eysuvis 0.25% falls within the range
Polycarbophil	Expressly claimed	Substitution may avoid narrow claims	Must compare actual excipients
HPMC	Expressly claimed	Alternative cellulose may reduce risk	Product-specific analysis required
Method claims	Postoperative inflammation and uveitis	Label carve-out may reduce exposure	Indication and dosing language matter
Biosimilar pathway	Not applicable	ANDA pathway applies	All are small molecules, not biologics

Biosimilar risk is not relevant because loteprednol etabonate is a small-molecule drug. The relevant regulatory pathway is an ANDA under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not a biosimilar application under section 351(k) of the Public Health Service Act.[4]

Key Takeaways

U.S. Patent 10,596,107 is a formulation and method-of-use patent centered on fine particle size and a polycarbophil/HPMC vehicle.
Claim 1 is broad in the active ingredient but requires both particle-size thresholds and two polymer classes.
Claims 8, 10, 13 and 17 provide the most commercially specific protection.
Claim 10 directly targets a 0.38 wt% loteprednol etabonate formulation associated with Lotemax SM.
The patent does not automatically cover every loteprednol ophthalmic product.
Dv50 and Dv90 testing will be central to infringement and design-around analysis.
Generic applicants may pursue noninfringement through alternative polymers, particle-size distributions or vehicle systems.
Biosimilar analysis is inapplicable; generic-entry analysis should focus on ANDA certification and Hatch-Waxman litigation.
The effective patent-expiration date must be determined from the priority chain, patent-term adjustment, terminal disclaimers and the current Orange Book listing.
Formulation, manufacturing and method-of-use patents may create additional barriers beyond U.S. 10,596,107.

FAQs

Does a 0.5% loteprednol product infringe U.S. Patent 10,596,107?

Not necessarily. Claims 9, 10 and 13 contain concentration limitations that do not reach every 0.5% product. Claim 1 remains potentially relevant if the product has the claimed particle size, carboxyvinyl polymer and nonionic cellulose derivative.

Can a generic avoid the patent by replacing HPMC with another cellulose polymer?

Potentially. The generic must determine whether the substitute is a nonionic cellulose derivative under the claim construction and whether the remaining formulation still satisfies all limitations of claim 1 or another asserted claim.

Does the patent cover loteprednol suspension manufacturing methods?

The provided claims do not contain an express manufacturing-process claim. Manufacturing activity could still be relevant if a process produces a product meeting the composition claims or if separate process patents exist in the same family or surrounding patent estate.

Are Dv50 and Dv90 measured from the finished product?

The governing measurement protocol depends on the patent specification, regulatory documentation and testing method. In litigation, sample preparation, dispersion conditions, instrument settings and the applicable claim construction can affect the result.

Is Lotemax SM protected only by U.S. Patent 10,596,107?

No. A commercial product may have multiple patents covering formulation, delivery, method of use, manufacturing or other product attributes. The complete Orange Book and patent-family record must be reviewed rather than relying on one patent number.

References

U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
U.S. Food and Drug Administration. (2019). Lotemax SM prescribing information. Bausch + Lomb Incorporated.
United States Patent and Trademark Office. (2024). Patent Center. https://patentcenter.uspto.gov/
U.S. Food and Drug Administration. (2024). Abbreviated new drug application (ANDA) process. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda
U.S. Patent No. 10,596,107. (2020). Ophthalmic suspension compositions and methods of use. United States Patent and Trademark Office.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bausch And Lomb Inc	LOTEMAX SM	loteprednol etabonate	GEL;OPHTHALMIC	208219-001	Feb 22, 2019	AB	RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial	Y			TREATMENT OF POST-OPERATIVE INFLAMMATION AND PAIN FOLLOWING OCULAR SURGERY	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2016211745	⤷ Start Trial
Australia	2021203027	⤷ Start Trial
Australia	2023248145	⤷ Start Trial
Australia	2025271194	⤷ Start Trial
Brazil	112017016016	⤷ Start Trial
Canada	2975106	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,596,107

Which drugs does patent 10,596,107 protect, and when does it expire?

Summary for Patent: 10,596,107