Details for Patent: 8,636,713

Which drugs does patent 8,636,713 protect, and when does it expire?

Patent 8,636,713 protects XIPERE and is included in one NDA.

This patent has twenty-five patent family members in fourteen countries.

Summary for Patent: 8,636,713

Title:	Methods and devices for drug delivery to ocular tissue using microneedle
Abstract:	Methods and devices are provided for targeted administration of a drug to a patient's eye. In one embodiment, the method includes inserting a hollow microneedle into the sclera of the eye at an insertion site and infusing a fluid drug formulation through the inserted microneedle and into the suprachoroidal space of the eye, wherein the infused fluid drug formulation flows within the suprachoroidal space away from the insertion site during the infusion. The fluid drug formulation may flow circumferentially toward the retinochoroidal tissue, macula, and optic nerve in the posterior segment of the eye.
Inventor(s):	Mark R. Prausnitz, Henry F. Edelhauser, Samirkumar Rajnikant Patel
Assignee:	Emory University , Georgia Tech Research Corp
Application Number:	US13/453,407
Patent Claim Types: see list of patent claims	Use; Formulation;

US Patent 8,636,713: Scope, Claim Construction, Expiration and Suprachoroidal Drug-Delivery Patent Landscape

US Patent 8,636,713 protects a procedure for delivering an anti-inflammatory formulation into the suprachoroidal space using a hollow microneedle. Its commercial significance is concentrated in the combination of scleral microneedle access, controlled infusion, posterior drug distribution and anti-inflammatory therapy. The patent is method-of-use focused; it does not independently claim a particular anti-inflammatory molecule, formulation composition or microneedle device.

The patent issued January 28, 2014, from an application directed to ocular delivery using microneedles. Based on the earliest disclosed priority date and the ordinary 20-year patent term, the expected base expiration is in late 2029, subject to patent-term adjustment, terminal disclaimers and maintenance-fee status. The patent should be analyzed with its continuation and divisional family members before making a freedom-to-operate or invalidity determination.[1]

What does US Patent 8,636,713 claim?

The independent claim requires the following elements:

Claim element	Required scope
Patient and target organ	An eye of a patient
Delivery instrument	A hollow microneedle with a tip-end opening
Insertion	The microneedle is inserted into the eye
Drug class	An anti-inflammatory drug formulation
Target compartment	The suprachoroidal space
Delivery mode	Infusion over a period of time
Distribution result	The formulation flows within the suprachoroidal space away from the insertion site

Claim 1 is a combination claim. A practicing party must satisfy every limitation. Use of a hollow microneedle alone does not infringe. Nor does injecting an anti-inflammatory drug into the vitreous, anterior chamber, subconjunctival space or intraretinal tissue. The claimed procedure requires infusion into the suprachoroidal space and movement away from the insertion site.

The claim does not expressly require:

• a specific steroid;
• a particular dose;
• a particular formulation vehicle;
• a specific microneedle diameter;
• a particular infusion pressure;
• a particular disease;
• a particular commercial device; or
• imaging guidance.

Those limitations appear in dependent claims.

How broad is claim 1?

Claim 1 is broader than the dependent claims in several important respects. It does not require the microneedle to be inserted through the sclera, although that is expressly required by claim 23. It also does not specify insertion angle, microneedle length, drug volume, infusion pressure or drug particle size.

The phrase "during the period the infused drug formulation flows within the suprachoroidal space away from the insertion site" creates a functional distribution limitation. The claim is directed to delivery that produces lateral or posterior movement within the suprachoroidal space, rather than merely placing a small quantity of drug at the needle tip.

A potential claim-construction issue is whether "away from the insertion site" requires a measurable distance or only movement in any direction away from the site. Claim 2 supplies a specific 5 mm distance as a dependent limitation, suggesting that claim 1 may cover movement of less than 5 mm. A court would assess the specification and prosecution history before assigning a definitive construction.

What do claims 2 through 10 add?

Claims 2 through 10 define the geometry, placement and operating parameters of the procedure.

Claims	Limitation	Commercial relevance
2	Drug flows at least 5 mm from insertion site	Supports posterior or circumferential distribution
3	Insertion site at about the equator	Covers mid-globe access
4	Site between equator and limbus	Covers anterior-to-equatorial scleral access
5	Drug reaches tissue posterior to equator	Targets posterior segment treatment
6	Microneedle enters at about 90 degrees	Defines perpendicular scleral insertion
7	Tip reaches base of sclera without complete penetration	Reduces risk of choroidal or retinal penetration
8	Tip passes through sclera into suprachoroidal space without penetrating choroid	Defines the intended anatomical route
9	Image-guided feedback	Covers ultrasound or other image-assisted positioning
10	Infused volume of about 10 to 200 microliters	Covers clinically relevant dosing volumes

Claims 3, 4 and 5 are not mutually exclusive in every factual setting. The equator is an anatomical reference point, while the requirement that drug reach posterior tissue concerns the distribution result. A procedure performed near the limbus could still fall within claim 4 and claim 5 if the formulation travels posteriorly.

Claim 8 is particularly important in infringement analysis. It requires passage through the sclera into the suprachoroidal space without penetration through the choroid. A device that intentionally penetrates the choroid would not satisfy that limitation, although it could raise infringement issues under claim 1 or other family patents if the remaining elements are met.

What formulation and infusion characteristics are protected?

Claims 11 through 15 extend the patent to specific formulation and delivery conditions.

Particle, aqueous and phase-change formulations

Claim 11 covers a suspension containing microparticles or nanoparticles that comprise the anti-inflammatory drug. Claim 12 narrows that suspension to one containing a physiologically acceptable aqueous vehicle.

Claim 13 covers a formulation that undergoes a phase change after infusion into the suprachoroidal space. A formulation that gels, precipitates, solidifies or otherwise changes physical state in situ could fall within this claim if the phase change is established as part of the administered formulation.

These claims create potential overlap with:

• depot steroid suspensions;
• biodegradable microparticle systems;
• nanoparticle suspensions;
• in situ gelling systems;
• thermoresponsive formulations; and
• formulations designed for sustained suprachoroidal residence.

The claims do not require a particular release period. A formulation may therefore be covered whether it provides short-duration or sustained drug exposure, provided the other limitations are met.

Infusion pressure

Claims 14 and 15 require infusion pressures of at least 150 kPa and at least 300 kPa, respectively. Claim 15 is narrower because it requires the higher pressure threshold.

At 150 kPa, the pressure is approximately 21.8 psi. At 300 kPa, it is approximately 43.5 psi. These limitations could become material in device testing and product-development diligence because pressure is often controlled by the syringe, plunger, actuator, needle geometry and formulation viscosity.

A competing delivery system may avoid claims 14 and 15 by operating below the claimed pressure thresholds. That does not avoid claim 1 if all claim 1 elements remain present.

What microneedle dimensions are covered?

Claims 16 through 21 define the microneedle structure.

Claims	Dimensional or structural limitation
16	Effective length between 500 and 1,000 microns
17	Effective length between 700 and 1,000 microns
18	Effective length between 800 and 1,000 microns
19	Maximum inserted width or diameter of 400 microns
20	Metal microneedle; 500-1,000 micron effective length; 200-400 micron shaft diameter; beveled tip under about 400 microns
21	Microneedle extends substantially perpendicularly from planar or convex base

The claims describe a scleral microneedle that is long enough to cross the sclera but short enough to reduce the risk of penetrating the choroid. Claim 20 is the most device-specific dependent claim and is likely to be relevant when evaluating metal microneedles with cylindrical shafts and beveled tips.

The term "effective length" may create an evidentiary issue. Measurement could depend on whether length is taken from the mounting base, planar surface, convex surface or point of emergence. The specification and prosecution record should control the interpretation.

Which diseases and anti-inflammatory drugs fall within the claims?

Claim 22 identifies uveitis, glaucoma, diabetic retinopathy, diabetic macular edema, wet or dry age-related macular degeneration, choroidal neovascularization and cytomegalovirus retinitis.

The disease list is dependent and does not limit claim 1. A method treating another inflammatory ocular condition could still fall within claim 1 if the drug is anti-inflammatory and the delivery route and flow limitations are satisfied.

Claims 24 through 29 cover broad anti-inflammatory categories:

• steroidal compounds;
• non-steroidal compounds; and
• cytokine antagonists.

Claim 27 names betamethasone, clobetasone, dexamethasone, fluorometholone, hydrocortisone and prednisolone. Claim 28 names antazoline, bromfenac, diclofenac, indomethacin, lodoxamide, saprofen and sodium cromoglycate. Claim 29 identifies tumor necrosis factor alpha as the relevant cytokine.

Is triamcinolone acetonide covered?

Triamcinolone acetonide is not listed in claim 27. That does not by itself exclude it. Claim 24 covers a steroidal compound, and claim 1 covers an anti-inflammatory drug formulation generally. A triamcinolone acetonide formulation could therefore fall within the broader claims if it is infused through a hollow microneedle into the suprachoroidal space and flows away from the insertion site.

This is commercially relevant to XIPERE, Clearside Therapeutics' suprachoroidal triamcinolone acetonide product for macular edema associated with uveitis. FDA approved XIPERE in 2021, and its delivery system uses a proprietary microneedle-based suprachoroidal administration approach.[2]

Is claim 30 internally consistent?

Claim 30 depends on claim 27 but states that "the cytokine is interleukin-1 beta." Claim 27 concerns steroidal compounds and does not introduce a cytokine limitation. The dependency therefore appears internally inconsistent on its face.

The legal effect depends on the issued patent text, certificate of correction, prosecution history and applicable claim-construction principles. Claim 30 should not be treated as a reliable standalone cytokine-antagonist claim without reviewing those records.

When does US Patent 8,636,713 lose exclusivity?

The patent issued in 2014 and is expected to remain in force until approximately December 2029 based on the ordinary term measured from the earliest nonprovisional filing in the family.[1]

Event	Date or status
Earliest family priority	2009-era priority, according to published family records
Patent issuance	January 28, 2014
Base 20-year expiration	Approximately late 2029
Patent-term adjustment	Must be confirmed in USPTO Patent Center
Maintenance fees	Required at 3.5, 7.5 and 11.5 years after issuance
Patent status	Requires current USPTO status verification

The expiration of 8,636,713 would not necessarily eliminate all suprachoroidal-delivery risk. Continuations, divisionals, formulation patents, device patents, method-of-use patents and regulatory exclusivity may extend the commercial barrier.

What is the Orange Book status of US Patent 8,636,713?

Orange Book listing is product-specific. A patent is not listed merely because it covers a technology used by an approved product.

For a product such as XIPERE, the relevant question is whether the patent claims an approved method of using the drug, drug substance or drug product and whether the sponsor submitted it for listing under FDA regulations. A patent directed primarily to microneedle delivery may be eligible for method-of-use listing if its claims read on the approved use, but listing cannot be inferred from the patent alone.[3]

The Orange Book should be checked for:

• XIPERE;
• triamcinolone acetonide injectable suspensions;
• patent-use codes;
• listed patent expiration dates;
• pediatric extensions; and
• any later-listed continuation patents.

Which companies are challenging the patent?

A Paragraph IV challenge is filed against an approved drug's listed patent, not against a patent in isolation. A generic applicant would need to submit an ANDA for a product that references an approved product and certify against listed patents.

No conclusion about a Paragraph IV challenge can be drawn from the claim text. The relevant records are the Orange Book, FDA ANDA litigation listings, district-court dockets and any notices under 21 U.S.C. § 355(j)(2)(B).[3]

For XIPERE, the principal commercial threat is more likely to arise from a competing suprachoroidal corticosteroid product or a generic triamcinolone formulation than from a conventional intravitreal generic. A conventional intravitreal product would not practice the claimed suprachoroidal delivery route.

What patent litigation and settlement agreements affect the patent?

Patent 8,636,713 should be searched in:

• USPTO Patent Center;
• PACER;
• district-court patent dockets;
• PTAB proceedings;
• Federal Circuit opinions;
• FDA Orange Book records; and
• SEC filings of Clearside Therapeutics and relevant licensees.

The patent number itself does not establish a litigation history, settlement agreement or license scope. The commercial rights surrounding suprachoroidal delivery have involved university-originated technology, company licenses and product-specific patent portfolios. A license to practice one patent does not necessarily grant rights under continuation patents or patents owned by other parties.

The principal diligence issue is chain of title. The review should reconcile the original assignee, later assignments, exclusive licensees, security interests and any government or university rights. Patent ownership and the right to sue may differ if the commercial party holds only an exclusive license.

How strong is the patent estate?

The estate has meaningful practical coverage because claim 1 combines the delivery route and therapeutic class, while dependent claims target the dimensions used by a microneedle-based ocular delivery platform.

Strength factor	Assessment
Route coverage	Strong for suprachoroidal infusion through a hollow microneedle
Drug coverage	Broad for anti-inflammatory agents
Formulation coverage	Moderate; dependent claims cover particles, aqueous vehicles and phase changes
Device coverage	Narrower; dimensions and metal construction appear in dependent claims
Product-specific coverage	Depends on continuation and product patents
Design-around exposure	Possible through alternative routes, non-microneedle delivery or altered procedure parameters
Invalidity exposure	Depends on prior-art combinations involving suprachoroidal injection, microneedles and ocular drug delivery
Remaining term	Approximately four years from 2025, subject to verified term adjustments

The central validity question is whether earlier references disclose, in combination, the use of a hollow microneedle to infuse an anti-inflammatory formulation into the suprachoroidal space with flow away from the insertion site. Separate references disclosing microneedles, ocular injections or suprachoroidal anatomy may not anticipate every limitation individually, but they may be relevant to obviousness.

What generic and competitive-entry scenarios exist?

Conventional intravitreal generic

A conventional intravitreal steroid or anti-VEGF generic generally presents limited direct risk under this patent because it uses a different anatomical route and usually a conventional hypodermic needle.

Competing suprachoroidal product

A competing product using a hollow microneedle and anti-inflammatory formulation presents the highest literal infringement risk. Risk increases if it uses:

• scleral insertion;
• 500-1,000 micron microneedles;
• 10-200 microliter dosing;
• posterior drug distribution;
• metal beveled needles; or
• pressure-driven infusion.

Alternative suprachoroidal device

A non-hollow device, implant, catheter or cannula may avoid claim 1's hollow-microneedle requirement. It may still implicate separate family patents or other third-party patents.

Alternative drug class

The claims are directed to anti-inflammatory drugs. A non-anti-inflammatory therapeutic delivered to the suprachoroidal space may avoid the principal claim, although claim classification can become fact-specific where the molecule has both anti-inflammatory and non-inflammatory effects.

Key Takeaways

• US 8,636,713 is a method patent for hollow-microneedle infusion of an anti-inflammatory formulation into the suprachoroidal space.
• Claim 1 requires movement of the formulation away from the insertion site, not merely drug placement at the needle tip.
• The patent covers broad anti-inflammatory use and is not limited to the molecules named in dependent claims.
• Triamcinolone acetonide may fall within the broad steroid and anti-inflammatory claims even though it is not expressly listed.
• Claims 8, 10, 14-20 and 23 are important for device-level infringement analysis.
• Claim 30 appears internally inconsistent because it depends on a steroid claim while reciting a cytokine.
• The expected base expiration is approximately late 2029, subject to verified patent-term adjustment and maintenance status.
• XIPERE creates the most relevant commercial overlap, but its full risk profile depends on the entire patent family, Orange Book listings and product-specific patents.
• A conventional intravitreal generic is less likely to practice the claimed route than a competing microneedle-based suprachoroidal product.

FAQs

Does US 8,636,713 cover the XIPERE delivery method?

It may cover the core method if XIPERE uses a hollow microneedle to infuse an anti-inflammatory triamcinolone formulation into the suprachoroidal space with movement away from the insertion site. Product-specific infringement requires comparison with the issued claims and the actual labeled and commercial procedure.

Can a company avoid the patent by using a longer microneedle?

Not necessarily. Claims 16-20 contain length and diameter limitations, but claim 1 does not specify a microneedle length. A longer microneedle could avoid some dependent claims while still implicating claim 1 if it satisfies the independent claim.

Does the patent cover anti-VEGF drugs?

The patent claims anti-inflammatory drugs. An anti-VEGF product would not automatically fall within the claims unless it is shown to satisfy the anti-inflammatory limitation and all other elements of the asserted claim.

Can a formulation patent provide protection after 2029?

Yes. A separate formulation, device, manufacturing or method-of-use patent may expire later than US 8,636,713. The later patent must be analyzed independently and cannot be assumed to extend the term of this patent.

Is biosimilar risk relevant to this patent?

Biosimilar risk is limited because US 8,636,713 is not a biologic-composition patent. Its relevance would arise if a biologic anti-inflammatory therapy were administered through the claimed hollow-microneedle suprachoroidal route.

References

1. United States Patent and Trademark Office. (2014). US Patent No. 8,636,713, Methods and apparatus for ocular delivery of therapeutic agents.
2. U.S. Food and Drug Administration. (2021). XIPERE (triamcinolone acetonide injectable suspension) prescribing information.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book.
4. United States Patent and Trademark Office. (2024). Patent Center and patent-term adjustment records.

Drugs Protected by US Patent 8,636,713

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	XIPERE	triamcinolone acetonide	SUSPENSION;INJECTION	211950-001	Oct 22, 2021		RX	Yes	Yes	8,636,713					TREATMENT OF MACULAR EDEMA ASSOCIATED WITH UVEITIS

International Family Members for US Patent 8,636,713

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2011248624
Australia	2015230874
Brazil	112012027416
Canada	2797258
China	102971030
China	104921868
European Patent Office	2563429