Details for Patent: 11,291,632

Which drugs does patent 11,291,632 protect, and when does it expire?

Patent 11,291,632 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: 11,291,632

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, Jose Luis Velada, Dominique Drouin
Assignee:	Laboratorios Leon Farma SA
Application Number:	US17/346,139
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 11,291,632
Patent Claim Types: see list of patent claims	Composition; Formulation; Compound; Dosage form;

United States Drug Patent 11,291,632: Scope, Claims, Expiration, and Drospirenone Patent Landscape

U.S. Patent No. 11,291,632 protects specific oral drospirenone compositions, including the 4 mg estrogen-free formulation marketed as Slynd. The patent does not broadly cover drospirenone, all drospirenone tablets, or all contraceptive uses. Its central limitations are particle-size distribution, dose, delayed dissolution, absence of estrogen, and, in narrower claims, fasting pharmacokinetics.

The strongest commercial risk is for a generic 4 mg drospirenone product that uses a materially similar formulation and release profile. A generic manufacturer can reduce literal infringement risk by changing particle-size distribution, dissolution behavior, dose, or formulation architecture, although it may then face bioequivalence and product-development constraints.

What drug and product does U.S. Patent 11,291,632 cover?

The compound identified in the claims is drospirenone, a synthetic progestin. The claimed composition corresponds closely to the active pharmaceutical ingredient and dose used in Slynd, an estrogen-free oral contraceptive containing 4 mg drospirenone.

The patent issued on March 29, 2022. Its claim set is directed to pharmaceutical compositions rather than:

• A new chemical entity;
• A general method of contraception;
• A manufacturing process for drospirenone;
• A broad genus of progestins;
• A drug-device combination; or
• A biologic or biosimilar product.

The patent should therefore be analyzed as a formulation patent with pharmacokinetic limitations.

Attribute	Patent 11,291,632
Active ingredient	Drospirenone
Product type	Oral pharmaceutical composition
Claimed dose range	3 mg to 4.5 mg
Most commercially relevant dose	About 4 mg
Estrogen	Expressly excluded
Dosage forms	Tablet or capsule
Particle-size limitations	Median 10-60 μm; d90 below 100 μm; d10 above 3 μm
Early dissolution limitation	No more than 50% dissolved within 30 minutes
Extended dissolution limitation	At least 55% dissolved within four hours, in claim 15
Pharmacokinetic limitations	Mean Tmax 2.2-6 hours; mean Cmax below 30 ng/mL; AUC0-tlast at least 300 ng·h/mL in claim 21
Issue date	March 29, 2022
Commercial relevance	Estrogen-free 4 mg drospirenone contraceptive products

Source: U.S. Patent No. 11,291,632, claims 1-21.

What does independent claim 1 require?

Claim 1 requires a single pharmaceutical composition containing all of the following elements:

1. Drospirenone in particle form.
2. A median particle size from 10 μm to 60 μm.
3. A d90 particle size below 100 μm.
4. A d10 particle size above 3 μm.
5. Drospirenone in an amount from 3 mg to 4.5 mg.
6. One or more pharmaceutically acceptable excipients.
7. No estrogen.
8. A dissolution profile in which no more than 50% of the initially present drospirenone dissolves within 30 minutes under the specified USP XXIII Paddle Method.

The claim uses "comprising." That term generally makes the claim open-ended. A product may contain additional ingredients and still fall within the claim, provided it satisfies every required limitation.

The absence of estrogen is a substantive limitation. A combined oral contraceptive containing ethinyl estradiol, estetrol, or another estrogen would not literally satisfy claim 1, even if its drospirenone particle size, dose, and dissolution profile otherwise matched.

How narrow are the particle-size limitations?

The particle-size limitations are central to the patent's scope.

Parameter	Claimed range or threshold	Practical significance
Median particle size	10-60 μm	Controls the central particle-size distribution
d90	Less than 100 μm	Excludes an excessively coarse upper tail
d10	More than 3 μm	Excludes a substantial fine-particle fraction
Dissolution at 30 minutes	No more than 50%	Requires relatively restrained early release

All three particle-size requirements must be met. A formulation with a median size of 20 μm but a d90 of 120 μm would not literally satisfy claim 1. Similarly, a formulation with a compliant median and d90 but a d10 of 2 μm would fall outside the literal particle-size limitations.

The claim does not specify a single particle-sizing technology. Laser diffraction, sieve analysis, microscopy, or another analytical method could produce different results. That creates potential claim-construction and infringement disputes concerning:

• The sampling procedure;
• Dispersion conditions;
• Agglomeration;
• Wet versus dry measurement;
• Volume-based versus number-based distributions;
• Instrument calibration; and
• Whether the tested particles are representative of the commercial batch.

A generic applicant would normally need a documented particle-size control strategy because particle size can affect dissolution, content uniformity, processability, and bioequivalence.

What excipients and dosage forms are protected?

Claims 2-14 add formulation categories and dosage-form limitations. The excipient claims are broad because they cover classes and combinations rather than a single proprietary excipient system.

Fillers

Claim 3 covers fillers including:

• Lactose;
• Microcrystalline cellulose;
• Starch;
• Pregelatinized or modified starch;
• Dibasic calcium phosphate dihydrate;
• Calcium sulfate;
• Calcium carbonate;
• Dextrose;
• Sucrose;
• Mannitol; and
• Sorbitol.

A formulation does not avoid claim 3 merely by replacing one listed filler with another listed filler. The claim covers combinations as well as individual excipients.

Lubricants, binders, and glidants

Claim 5 identifies common lubricants such as magnesium stearate, calcium stearate, talc, stearic acid, polyethylene glycol, sodium lauryl sulfate, and mineral oil-based materials.

Claims 7-9 cover common binders, including starches, gums, gelatin, microcrystalline cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, and polyvinylpyrrolidone.

Claim 11 covers glidants such as silicon dioxide, magnesium trisilicate, powdered cellulose, starch, talc, and tribasic calcium phosphate.

These dependent claims are unlikely to create a major barrier by themselves because many generic formulations use conventional excipients. Their value is cumulative: a tablet containing compliant drospirenone particles, a covered filler, a covered lubricant, and the claimed dissolution profile can satisfy multiple claims simultaneously.

Tablets, capsules, and coatings

Claim 12 covers tablets. Claim 19 covers capsules. Claim 13 adds a coating, and claim 14 identifies hydroxypropylmethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose as coating materials.

A tablet-to-capsule switch does not necessarily avoid the patent because both dosage forms are expressly claimed. An uncoated tablet may avoid claims 13 and 14 but can remain within claim 12 and claim 1.

What dose strengths are covered?

Claims 16-18 narrow the dose:

Claim	Dose limitation
Claim 1	3 mg to 4.5 mg
Claim 16	3.0 mg to 3.5 mg
Claim 17	About 3.5 mg
Claim 18	About 4.0 mg

The 4 mg product is within claim 1 and claim 18, assuming the other limitations are satisfied. The "about" language in claim 17 and claim 18 may create a factual dispute over acceptable manufacturing and assay variation. A nominal 4.0 mg product is the clearest commercial target for claim 18.

A product containing 5 mg drospirenone would be outside the express dose range of claim 1, but it would not necessarily be commercially viable as a substitute for a 4 mg contraceptive product.

What dissolution profile does the patent require?

Claim 1 requires that no more than 50% of the initial drospirenone dissolve within 30 minutes under the USP XXIII Paddle Method. Claim 15 adds the requirement that at least 55% dissolve within four hours.

The combined profile requires a relatively controlled release pattern:

• At 30 minutes: 50% or less dissolved.
• At four hours: 55% or more dissolved.

This is not an extended-release claim in the conventional sense because the patent does not require a particular matrix, coating, osmotic system, or release mechanism. It claims the measured dissolution result.

Important variables include:

• Paddle speed;
• Dissolution medium;
• Medium volume;
• Temperature;
• Sampling intervals;
• Sink conditions;
• Filtration;
• Assay method; and
• Whether the test uses intact tablets, capsules, or extracted particles.

The claim refers to the USP XXIII Paddle Method but does not, in the supplied claim text, specify every operating parameter. Those omitted parameters could become important in litigation.

What pharmacokinetic profile is protected?

Claim 20 depends on claim 1 and requires a fasting oral pharmacokinetic profile with:

• Mean Tmax from 2.2 to 6 hours; and
• Mean Cmax below 30 ng/mL.

Claim 21 adds:

• AUC0h-tlast of at least 300 ng·h/mL.

These are product-performance limitations, not merely formulation ingredients. A competing product could infringe even if it uses different excipients if the composition satisfies claim 1 and produces the claimed pharmacokinetic profile.

The PK limitations also create evidentiary issues. Infringement would likely require a controlled study or reliable comparative data. Results may vary with:

• Subject population;
• Fasting protocol;
• Sample size;
• Bioanalytical method;
• Formulation batch;
• Statistical treatment of mean values; and
• The definition of the last measurable concentration.

Because claims 20 and 21 depend on claim 1, a product that meets the PK profile but fails the particle-size or dissolution limitations should not literally infringe those claims.

When does U.S. Patent 11,291,632 lose exclusivity?

The patent issued March 29, 2022. Based on the apparent 2014 international or nonprovisional filing lineage for this drospirenone formulation family, the ordinary 20-year patent term is expected to reach approximately December 2034, before any patent-term adjustment or patent-term extension.

The operative expiration date should be determined from the USPTO patent-term calculation and the Orange Book listing. Any adjustment for USPTO examination delay could extend the date beyond the nominal 20-year endpoint. A Hatch-Waxman patent-term extension for the product would require a regulatory basis and cannot be inferred solely from the claim text.

Milestone	Date or status
U.S. patent issue	March 29, 2022
Nominal family term	Approximately December 2034
Potential PTA	Must be added if awarded
FDA product	Slynd, drospirenone 4 mg
FDA approval of Slynd	2019
Likely generic pathway	ANDA, not biosimilar

What is the Orange Book status of the patent?

Slynd is an FDA-approved small-molecule drug. Generic competitors would generally use the ANDA pathway under section 505(j) of the Federal Food, Drug, and Cosmetic Act. The relevant patent questions are therefore Orange Book listing, certification, and potential Paragraph IV litigation rather than biosimilar interchangeability.

Patent 11,291,632 is commercially relevant to Slynd because its claims track the product's estrogen-free drospirenone formulation, dose, particle characteristics, and release behavior. The Orange Book listing, if maintained for the approved product, can require an ANDA applicant to make one of the statutory patent certifications.

An ANDA applicant could:

• Certify that no listed patent information has been filed;
• Certify that the patent has expired;
• Certify that the applicant will not market before expiration; or
• Make a Paragraph IV certification asserting that the patent is invalid, unenforceable, or not infringed.

The claim text alone does not establish whether a particular generic company has filed a Paragraph IV certification or whether litigation has commenced. A Paragraph IV notice would create potential litigation under 35 U.S.C. §271(e)(2), with a possible 30-month stay of FDA approval under 21 U.S.C. §355(j)(5)(B)(iii), subject to statutory exceptions.

Which companies are challenging the patent?

No challenger, Paragraph IV notice, settlement, or final infringement judgment can be established from the supplied patent claims alone.

The relevant competitive set consists of:

• The Slynd product sponsor and its patent or commercial affiliates;
• ANDA applicants seeking approval for drospirenone 4 mg tablets;
• Contract manufacturers supplying drospirenone drug substance or finished dosage forms; and
• Developers of alternative progestin-only oral contraceptives.

A generic company could challenge the patent through a Paragraph IV certification, pursue a formulation that falls outside one or more claim limitations, or defer launch until expiration. The absence of an identified challenger in the supplied material should not be treated as evidence that no challenge exists.

How does this patent compare with older drospirenone patents?

Older drospirenone patents generally concern the active compound, contraceptive combinations, treatment methods, or earlier drospirenone formulations. Products such as Yaz and Yasmin combine drospirenone with estrogen and therefore do not fall within claim 1's estrogen-free limitation.

Patent category	Typical subject matter	Relationship to Patent 11,291,632
Compound patents	Drospirenone and related steroid compounds	Earlier foundational protection
Combination-product patents	Drospirenone plus estrogen	Outside claim 1 because estrogen is excluded
Method-of-use patents	Contraception, premenstrual dysphoric disorder, acne, or related uses	Separate from the composition claims
Formulation patents	Particle size, dose, dissolution, or PK	Closest competitive overlap
Manufacturing patents	Synthesis, purification, crystallization, or milling	May create separate process barriers
Patent 11,291,632	Estrogen-free 3-4.5 mg composition with defined particle and release characteristics	Directly relevant to Slynd-style products

The patent is stronger against a close copy of the approved 4 mg product than against a product designed around different particle characteristics or a substantially different release profile.

How strong is the patent estate?

The claim set has moderate commercial strength and narrower legal breadth.

Strengths

• It covers the commercially important 4 mg estrogen-free dose.
• It combines multiple measurable formulation parameters.
• It includes both tablets and capsules.
• It captures common excipient systems through dependent claims.
• It adds dissolution and PK claims that can complicate design-around efforts.
• The claims are product claims, which can support an ANDA-based infringement action if the proposed product meets the limitations.

Vulnerabilities

• Particle-size limitations are measurable and potentially designable.
• The dose range is narrow.
• Estrogen-containing products are excluded.
• Dissolution conditions may invite testing and claim-construction disputes.
• Claims 20 and 21 require clinical or bioanalytical evidence.
• Many dependent claims use conventional excipients that may add limited exclusivity value.
• A generic applicant may challenge validity based on obviousness, written description, enablement, indefiniteness, or anticipation, depending on the prior-art record.

The main validity pressure point is whether the claimed combination of drospirenone particle distribution, dose, delayed dissolution, and estrogen-free formulation was adequately supported and non-obvious over prior drospirenone formulations. The main infringement pressure point is whether the proposed generic's tested particle and dissolution profiles fall within the claimed boundaries.

What generic launch scenarios exist?

Launch after ordinary expiration

This is the lowest litigation-risk path if the patent remains enforceable through its ordinary or adjusted expiration date.

Paragraph IV launch

A generic may certify that the patent is invalid, unenforceable, or not infringed. The sponsor could sue within the statutory period, potentially delaying approval through the 30-month stay mechanism.

Design-around launch

A generic could attempt to use:

• A median particle size below 10 μm or above 60 μm;
• A d90 at or above 100 μm;
• A d10 at or below 3 μm;
• A dose outside 3-4.5 mg;
• An estrogen-containing composition;
• A dissolution profile exceeding 50% at 30 minutes; or
• A formulation that does not produce the claimed PK profile.

Each design-around must still satisfy FDA quality, performance, and bioequivalence requirements. Avoiding one claim limitation may create a regulatory disadvantage.

Authorized or licensed generic

A licensed or authorized generic could reduce litigation exposure through an agreement with the patent owner or product sponsor. No such agreement can be confirmed from the supplied information.

What manufacturing and IP barriers remain after this patent?

Patent 11,291,632 is not the only potential barrier. A competitor may also face:

• Drospirenone drug-substance patents;
• Crystallization or polymorph claims;
• Milling and particle-engineering know-how;
• Tablet compression and content-uniformity controls;
• Dissolution-method development;
• Stability and moisture-control requirements;
• Other Orange Book-listed patents;
• Regulatory exclusivity;
• Trade-secret manufacturing processes; and
• Contract-manufacturing capacity constraints.

Particle-size control is particularly important because the claim requires a bounded distribution rather than merely an average size. A manufacturer must control milling, sieving, agglomeration, blending, and sampling throughout commercial production.

Key Takeaways

• U.S. Patent 11,291,632 is a formulation patent centered on estrogen-free drospirenone compositions.
• Claim 1 requires a specific particle-size distribution, 3-4.5 mg dose, excipients, absence of estrogen, and delayed early dissolution.
• The 4 mg Slynd formulation is the principal commercial product implicated by the claims.
• Claims 15, 20, and 21 add extended dissolution and fasting PK requirements.
• The patent does not broadly cover all drospirenone products or all contraceptive methods.
• The nominal patent term appears to run to approximately December 2034, subject to patent-term adjustment.
• Generic applicants would ordinarily use the ANDA pathway and could pursue a Paragraph IV challenge or a formulation design-around.
• Biosimilar risk is not applicable because drospirenone is a chemically synthesized small molecule.
• The strongest design-around opportunities involve particle-size distribution, dissolution behavior, and formulation architecture.
• The patent's commercial strength is highest against a close copy of the approved 4 mg estrogen-free product.

FAQs

Does U.S. Patent 11,291,632 cover Yaz or Yasmin?

No. Yaz and Yasmin contain estrogen, while claim 1 expressly requires that the composition not comprise estrogen.

Can a generic use a different filler and avoid the patent?

Not necessarily. The patent claims the broader composition in claim 1 and separately lists filler classes in claim 3. Changing the filler does not avoid claim 1 if the particle-size, dose, estrogen, and dissolution limitations remain satisfied.

Does a capsule avoid infringement because Slynd is a tablet?

No. Claim 19 expressly covers a capsule formulation. A capsule must still be tested against the other limitations of claim 1.

Is a 3 mg drospirenone product outside the patent?

No. Three milligrams is within claim 1. It may also fall within the narrower 3.0-3.5 mg range in claim 16 if the remaining limitations are met.

Can a product with the same 4 mg dose avoid the patent by changing its release profile?

Potentially. A product that dissolves more than 50% within 30 minutes may fall outside claim 1's express dissolution limitation, but other listed patents, regulatory requirements, or equivalent infringement theories could remain relevant.

References

1. U.S. Patent No. 11,291,632. (2022, March 29). Pharmaceutical composition comprising drospirenone. United States Patent and Trademark Office.

2. U.S. Food and Drug Administration. (2019). Slynd (drospirenone) tablets, 4 mg: Prescribing information. FDA.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.

4. U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.

5. U.S. Code, 21 U.S.C. §355(j).

6. U.S. Code, 35 U.S.C. §271(e)(2).

Drugs Protected by US Patent 11,291,632

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 11,291,632

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
European Patent Office	2588114		C202030026	Spain
European Patent Office	2588114		301123	Netherlands
European Patent Office	2588114		PA2021523	Lithuania
European Patent Office	2588114		LUC00227	Luxembourg