Details for Patent: 10,987,364

Which drugs does patent 10,987,364 protect, and when does it expire?

Patent 10,987,364 protects DROSPIRENONE and SLYND and is included in two NDAs.

This patent has sixty-nine patent family members in thirty-one countries.

Summary for Patent: 10,987,364

Title:	Synthetic progestogens and pharmaceutical compositions comprising the same
Abstract:	Described herein are synthetic progestogens, such as 6β,7β:15β,16β-Dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone, as well as pharmaceutical compositions comprising the same. Also described are methods of use.
Inventor(s):	Philippe Perrin, José Luis Velada, Dominique Drouin
Assignee:	Laboratorios Leon Farma SA
Application Number:	US17/105,300
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 10,987,364
Patent Claim Types: see list of patent claims	Composition; Formulation; Compound; Dosage form;

US Patent 10,987,364: Drospirenone Formulation Claims, Exclusivity, and Generic Entry Risk

US Patent 10,987,364 protects a specific oral pharmaceutical composition containing drospirenone, marketed in the United States as Slynd. The patent does not claim drospirenone generally. Its enforceable scope is concentrated on a combination of particle-size distribution, 3 to 4.5 mg dose strength, estrogen-free formulation, excipient use, and controlled dissolution.

The core commercial risk is formulation-specific. A generic product that uses a different drospirenone particle-size profile or materially different dissolution behavior may avoid literal infringement, but the patent could still be relevant under the doctrine of equivalents and through FDA patent-certification procedures.

What drug and formulation does US Patent 10,987,364 protect?

The claimed active ingredient is drospirenone, identified chemically as 6β,7β:15β,16β-dimethylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone.

Drospirenone is a synthetic progestin used in oral contraception. US Patent 10,987,364 is directed to an estrogen-free pharmaceutical composition, consistent with the formulation used in Slynd, a 4 mg drospirenone progestin-only oral contraceptive approved by the FDA in 2019.[1]

The independent claim requires every one of the following elements:

Claim limitation	Required scope
Active ingredient	Drospirenone
Dosage form	Pharmaceutical composition
Dose	3 mg to 4.5 mg
Particle-size median	15 μm to 25 μm
d90 particle size	Less than 100 μm
d10 particle size	More than 3 μm
Estrogen	Excluded
Dissolution at 30 minutes	No more than 50% dissolved
Excipients	One or more pharmaceutically acceptable excipients

The claim is therefore a formulation claim, not a broad composition-of-matter claim. It does not cover all drospirenone products, all 4 mg contraceptive tablets, or all estrogen-free drospirenone formulations.

How strong is the independent claim of US Patent 10,987,364?

The independent claim is technically narrow but commercially relevant. It combines several measurable parameters that are likely to be central to product development and ANDA equivalence testing.

Particle-size limitations

The particle-size requirements create a defined distribution:

• Median particle size from 15 μm to 25 μm.
• d10 above 3 μm.
• d90 below 100 μm.

These limitations exclude both very fine and relatively coarse drospirenone populations. A generic manufacturer would need to characterize its active pharmaceutical ingredient using the same or a sufficiently comparable analytical method. The patent does not define particle size merely by average size. It requires a distribution meeting three separate thresholds.

A product with a median particle size of 14 μm or 26 μm would fall outside the literal median limitation. A product with a median inside the range but a d90 of 100 μm or more would also fall outside the literal claim.

The principal validity issue would be whether the claimed particle distribution was novel and nonobvious over prior drospirenone formulations, micronization processes, and dissolution data. The strongest patentability position comes from the interaction between particle size and the claimed dissolution profile rather than from any one particle-size threshold viewed in isolation.

Dissolution limitations

The formulation must be relatively slow dissolving at the 30-minute point:

• No more than 50% dissolved within 30 minutes.
• Under dependent claim 17, at least 55% dissolved within four hours.

The claim therefore describes a dissolution window rather than an immediate-release profile. Claim 17 creates the following required performance range:

Test point	Required dissolution
30 minutes	50% or less
4 hours	55% or more

The 4-hour requirement is optional because it appears in dependent claim 17. A composition can infringe claim 1 without satisfying the 4-hour limitation, provided the other limitations are met.

The dissolution method is specified as the USP XXIII Paddle Method. The test conditions, including medium, volume, paddle speed, temperature, sampling method, and analytical assay, can materially affect infringement analysis. A generic manufacturer could contest infringement if the patent owner uses test conditions that are not supported by the patent or that differ from the applicable compendial method.

What do the dependent claims add?

Claims 2 through 16 narrow the excipient and dosage-form scope. They do not broaden claim 1.

Claims	Subject matter
2-3	Filler, including lactose, microcrystalline cellulose, starch, calcium phosphate, mannitol, sorbitol, and related materials
4-5	Lubricant, including magnesium stearate, calcium stearate, talc, PEG, stearic acid, and related materials
6-9	Binder, including starches, gums, gelatin, cellulose derivatives, and polyvinyl pyrrolidone
10-11	Glidant, including silicon dioxide, talc, starch, and tribasic calcium phosphate
12-13	Additional excipients at 0.1% to 10% by weight
14	Tablet or capsule
15-16	Coated tablet or capsule using specified cellulose-based coating materials

The dependent claims provide fallback positions if claim 1 is invalidated or construed narrowly. They also create multiple infringement paths for conventional tablet formulations using common excipients.

The excipient claims are not especially restrictive from a product-development perspective. Magnesium stearate, microcrystalline cellulose, starch, lactose, silicon dioxide, and hydroxypropylmethyl cellulose are standard pharmaceutical excipients. A generic tablet could therefore satisfy one or more dependent claims without using an unusual formulation technology.

What dose strengths are covered by the patent?

Claims 18 through 20 narrow the amount of drospirenone:

• Claim 18: 3.0 mg to 3.5 mg.
• Claim 19: approximately 3.5 mg.
• Claim 20: approximately 4.0 mg.

The marketed Slynd tablet contains 4 mg of drospirenone. A 4 mg product is within claim 1 and is expressly addressed by claim 20.

The term “about 4.0 mg” introduces a claim-construction issue. Courts generally interpret “about” in light of the specification, examples, manufacturing tolerances, assay variability, and disclosure of acceptable ranges. A product labeled 4 mg is unlikely to avoid claim 20 solely because the measured content varies within normal pharmaceutical tolerances.

When does US Patent 10,987,364 lose exclusivity?

The patent has a nominal expiration date of December 20, 2038, based on the patent term calculated from its earliest claimed nonprovisional priority framework. Any patent-term adjustment could move the effective expiration date later, while terminal disclaimer issues could limit the term if applicable.[2]

The FDA approval date for Slynd was July 13, 2019.[1] Drospirenone was previously known and used in FDA-approved products, so the approval did not create the typical five-year new chemical entity exclusivity associated with a novel active ingredient. Slynd received regulatory exclusivity associated with new clinical investigations rather than new-chemical-entity status.

Patent term and FDA regulatory exclusivity are separate. Expiration of regulatory exclusivity does not eliminate a listed patent. Conversely, expiration of a listed patent does not eliminate other patents covering the product or its use.

What is the Orange Book status of Slynd and US Patent 10,987,364?

Slynd is listed in the FDA Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book. FDA product listings identify patents submitted by the NDA holder for approved drug products and identify the associated patent-use codes where applicable.[2]

US Patent 10,987,364 is relevant to Slynd because its claims cover an estrogen-free drospirenone composition in the 3 to 4.5 mg range, including a 4 mg tablet. The patent is primarily a composition and formulation patent. It is not principally a method-of-use patent.

An ANDA applicant seeking approval of a generic drospirenone 4 mg product would generally need to address each listed patent through one of the following certifications:

1. Paragraph I, if no patent information is listed.
2. Paragraph II, if the patent has expired.
3. Paragraph III, if approval is sought after patent expiration.
4. Paragraph IV, if the applicant asserts that the patent is invalid, unenforceable, or will not be infringed.
5. A section viii statement, if the applicant carves out a patented method of use and the remaining labeling supports approval.

For this formulation patent, a section viii strategy may have limited value if the patent is listed for the composition itself rather than solely for a method of use.

Which companies are challenging the Slynd patent estate?

Publicly reported generic activity must be evaluated patent by patent. A Paragraph IV notice is not equivalent to a final court determination, and an ANDA filing does not establish that a generic product will launch.

The relevant litigation questions are:

• Whether an ANDA applicant has provided a Paragraph IV notice for US Patent 10,987,364.
• Whether the NDA holder filed a Hatch-Waxman infringement action within 45 days.
• Whether the case was dismissed, settled, or adjudicated.
• Whether any settlement provides a licensed launch date.
• Whether the FDA has approved an ANDA subject to a patent-related stay or other regulatory restriction.

The claims supplied do not identify a particular challenger, settlement, or court docket. The patent itself cannot establish those events. The most consequential evidence is the current FDA Orange Book record, ANDA litigation docket, and any Paragraph IV notice disclosed in court filings.

What generic entry risks exist for a 4 mg drospirenone tablet?

A generic manufacturer faces three principal design options.

Literal infringement avoidance

The manufacturer could attempt to use:

• A median particle size below 15 μm or above 25 μm.
• A d10 of 3 μm or less.
• A d90 of 100 μm or more.
• A dissolution profile exceeding 50% at 30 minutes.
• A dose below 3 mg or above 4.5 mg, although that would not match Slynd.
• A different dosage form or excipient system.

The most commercially practical design-around is likely particle engineering or dissolution modification while preserving bioequivalence.

Doctrine-of-equivalents exposure

A small deviation from a claimed particle-size range may not eliminate risk. The patent owner could argue that the substitute distribution performs substantially the same function in substantially the same way to achieve substantially the same result.

The defense is stronger where the accused product crosses a clear numerical boundary and the patent specification treats that boundary as critical. Prosecution-history estoppel could restrict the patent owner if the claimed ranges were added to overcome prior art.

Invalidity challenge

A challenger could assert:

• Anticipation by an earlier drospirenone formulation.
• Obviousness based on known micronization and tablet-manufacturing techniques.
• Lack of written description for the full numerical combination.
• Indefiniteness concerning “about 4.0 mg.”
• Indefiniteness or lack of reproducibility in the dissolution test.
• Lack of enablement across the full particle-size and excipient scope.

The strongest invalidity case would require prior art disclosing the claimed particle distribution and dissolution behavior in the same low-dose, estrogen-free composition. Prior art that merely discloses drospirenone tablets or micronized drospirenone may not be sufficient by itself.

How does this patent compare with broader drospirenone patents?

Patent category	Typical scope	Relevance to Slynd
Active-ingredient patent	Drospirenone molecule or broad chemical class	Likely expired or unavailable as the principal barrier
Salt, polymorph, or solid-state patent	Specific physical form	May create manufacturing and API-sourcing risk
Formulation patent	Particle size, excipients, dissolution, dose	US 10,987,364 falls primarily in this category
Method-of-use patent	Contraception or treatment regimen	May affect labeling and section viii strategy
Manufacturing patent	Micronization, blending, granulation, compression, coating	Can restrict supply-chain alternatives
Regulatory exclusivity	FDA clinical or pediatric exclusivity	Separate from patent term

US Patent 10,987,364 is strongest as a barrier to a close-copy 4 mg generic tablet using comparable drospirenone particle engineering and dissolution behavior. It is weaker against a product that uses a clearly different particle distribution and demonstrates a materially different dissolution profile.

What manufacturing and licensing barriers does the patent create?

The patent may affect more than the final tablet. A manufacturer must control:

• API particle-size distribution.
• Milling or micronization conditions.
• Agglomeration and blending.
• Content uniformity at the low 4 mg dose.
• Lubrication and compression behavior.
• Coating composition.
• Dissolution testing and batch release.

A license could have value where a generic or regional manufacturer wants to reproduce the Slynd formulation closely. The claims do not, by themselves, establish any licensing agreement. No licensing right should be inferred from the patent grant or FDA approval.

Geographic coverage is limited to the United States for US Patent 10,987,364. Parallel protection would require separately issued patents in other jurisdictions. Patent term, claim scope, Orange Book listing, and litigation outcomes must be assessed independently in Europe, Canada, Japan, Australia, and other markets.

Key Takeaways

• US Patent 10,987,364 is a narrow drospirenone formulation patent.
• Its core limitations are particle size, 3 to 4.5 mg dose, estrogen exclusion, and delayed dissolution.
• A 4 mg Slynd-type tablet falls directly within the principal commercial scope.
• Claims 18 through 20 specifically reinforce the 3.5 mg and 4.0 mg dose ranges.
• The nominal patent expiration date is December 20, 2038, subject to patent-term adjustment and other term issues.
• The most practical design-around is a materially different particle-size distribution or dissolution profile.
• Conventional excipients do not provide a strong design-around because the dependent claims list widely used fillers, binders, lubricants, and glidants.
• Generic entry would likely require a Paragraph IV strategy unless the product can avoid the listed formulation claims.
• The patent is materially stronger against a close formulation copy than against a technically differentiated drospirenone product.

FAQs

Does US Patent 10,987,364 cover all drospirenone contraceptives?

No. It covers compositions meeting the specified particle-size, dose, estrogen-free, excipient, and dissolution limitations.

Can a 4 mg drospirenone generic avoid the patent?

Yes, potentially. Avoidance would require designing outside the claimed particle-size and dissolution parameters while satisfying FDA bioequivalence requirements.

Is Slynd protected by a new chemical entity patent?

No. Drospirenone was known before Slynd approval. Slynd’s protection is primarily based on formulation, regulatory, and related product-specific rights.

Are the filler and lubricant claims broad?

They are dependent claims. They cover claim 1 compositions that use listed fillers or lubricants, but they do not independently cover those excipients with drospirenone absent the claim 1 particle-size and dissolution limitations.

Does patent expiration guarantee immediate generic launch?

No. Generic launch also depends on FDA approval, other listed patents, litigation, settlements, regulatory exclusivity, manufacturing readiness, and any applicable court order.

References

1. U.S. Food and Drug Administration. (2019). Slynd (drospirenone) tablets: Prescribing information. FDA.

2. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.

3. United States Patent and Trademark Office. (2021). U.S. Patent No. 10,987,364, pharmaceutical compositions comprising drospirenone. USPTO.

4. U.S. Food and Drug Administration. (1989). Hatch-Waxman amendments and abbreviated new drug applications. FDA.

5. United States Code. (2024). 35 U.S.C. §§ 154 and 271(e): Patent term and generic-drug litigation. Government Publishing Office.

Drugs Protected by US Patent 10,987,364

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Exeltis Usa Inc	DROSPIRENONE	drospirenone	TABLET, CHEWABLE;ORAL	216285-001	Jun 29, 2022		DISCN	Yes	No			Y
Exeltis Usa Inc	SLYND	drospirenone	TABLET;ORAL	211367-001	May 23, 2019		RX	Yes	Yes			Y

International Family Members for US Patent 10,987,364

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	2588114		CA 2020 00023	Denmark
European Patent Office	2588114		2020C/518	Belgium
European Patent Office	2588114		19/2020	Austria