Ethynodiol diacetate; mestranol - Generic Drug Details

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What are the generic sources for ethynodiol diacetate; mestranol and what is the scope of patent protection?

Ethynodiol diacetate; mestranol is the generic ingredient in three branded drugs marketed by Gd Searle Llc and is included in two NDAs. Additional information is available in the individual branded drug profile pages.

Summary for ethynodiol diacetate; mestranol

US Patents:	0
Tradenames:	3
Applicants:	1
NDAs:	2
DailyMed Link:	ethynodiol diacetate; mestranol at DailyMed

US Patents and Regulatory Information for ethynodiol diacetate; mestranol

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Gd Searle Llc	OVULEN	ethynodiol diacetate; mestranol	TABLET;ORAL-20	016029-002	Approved Prior to Jan 1, 1982		DISCN	No	No
Gd Searle Llc	OVULEN-28	ethynodiol diacetate; mestranol	TABLET;ORAL-28	016705-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Gd Searle Llc	OVULEN-21	ethynodiol diacetate; mestranol	TABLET;ORAL-21	016029-003	Approved Prior to Jan 1, 1982		DISCN	No	No

Last updated: September 24, 2026

ecutive summary: Ethynodiol diacetate/mestranol is a legacy combined oral contraceptive with no meaningful current U.S. commercial trajectory. Its historical brands, including Demulen, competed in an estrogen-progestin market that shifted toward ethinyl estradiol formulations, lower-dose products, extended-cycle regimens, generics, and long-acting contraception. Composition and formulation patent protection has expired or lost practical commercial value. No active biosimilar issue exists, and current revenue exposure is likely immaterial because the product is not a major marketed contraceptive in the United States. Public sources do not provide reliable standalone revenue data for the active-ingredient combination.

Ethynodiol Diacetate and Mestranol Market Dynamics, Patent Status, and Financial Trajectory

What is ethynodiol diacetate and mestranol?

Ethynodiol diacetate/mestranol is a combined oral contraceptive containing:

Component	Pharmacologic role
Ethynodiol diacetate	Progestin
Mestranol	Estrogen prodrug converted primarily to ethinyl estradiol

The combination was developed as a daily oral contraceptive and marketed historically under brands including Demulen. Product strengths included formulations commonly identified as 1 mg ethynodiol diacetate with 35 micrograms of mestranol and 1 mg ethynodiol diacetate with 50 micrograms of mestranol.

Mestranol is pharmacologically related to ethinyl estradiol but requires metabolic conversion. Over time, manufacturers and prescribers favored direct ethinyl estradiol formulations, which reduced the commercial relevance of mestranol-based products.

What was the commercial history of Demulen?

Demulen was one of the older U.S. combined oral contraceptive brands. Its commercial history followed the pattern of many first-generation oral contraceptives:

1. Initial brand-market adoption after regulatory approval.
2. Competition from newer estrogen-progestin combinations.
3. Loss of differentiation after generic entry.
4. Declining prescribing as lower-dose and alternative delivery systems gained share.
5. Market withdrawal or limited availability.

The product competed against a large and rapidly expanding class. Major alternatives included oral contraceptives containing ethinyl estradiol with norethindrone, levonorgestrel, desogestrel, norgestimate, or drospirenone. These products often had more current labeling, stronger physician familiarity, and broader generic availability.

The economic value of Demulen was reduced by the absence of durable product differentiation. The combination did not retain a clinically exclusive indication, proprietary delivery system, or late-stage lifecycle product extension.

What is the current FDA regulatory status of ethynodiol diacetate and mestranol?

The combination is not a significant current U.S. branded contraceptive product. FDA regulatory records distinguish between products that have been discontinued for commercial reasons and products withdrawn for safety or efficacy reasons. A discontinuation entry alone does not establish a safety withdrawal. The FDA’s “Approved Drug Products with Therapeutic Equivalence Evaluations,” commonly known as the Orange Book, remains the primary source for current approval and therapeutic-equivalence information.[1]

Public FDA materials do not support treating ethynodiol diacetate/mestranol as a current growth product in the U.S. prescription market. Its commercial status is best characterized as legacy or discontinued rather than actively promoted.

FDA status summary

Issue	Assessment
Current U.S. commercial importance	Low
Current branded-market momentum	None identified
Regulatory pathway	Legacy NDA and generic oral contraceptive pathway
Active biologic competition	Not applicable
Biosimilar exposure	None
Current innovation cycle	None identified
Main commercial substitutes	Generic combined oral contraceptives and long-acting contraceptives

What patents protected ethynodiol diacetate and mestranol?

The original composition, formulation, and use patents associated with this product class are expired or commercially exhausted. The drug has been available for many decades, placing any original U.S. patent protection well beyond the standard patent term for pharmaceutical products.

A current freedom-to-operate analysis would focus less on the active ingredients and more on:

• Any country-specific formulation patent.
• Packaging or calendar-pack intellectual property.
• Manufacturing process claims.
• Combination claims covering a newer delivery system.
• Trademark rights associated with Demulen or successor brands.
• Regulatory exclusivity attached to a specific new product, if any.

No commercially meaningful, unexpired U.S. patent estate is apparent for the legacy ethynodiol diacetate/mestranol combination itself. Any historical patent numbers would have limited relevance to current entry because the statutory patent terms have elapsed.

Patent-estate assessment

Patent category	Current commercial relevance
Original active-ingredient composition	Expired
Original contraceptive combination	Expired or commercially exhausted
Oral-tablet formulation	Expired or no longer exclusionary
Method-of-use claims for contraception	Expired or unavailable as a practical barrier
Manufacturing-process claims	Potentially relevant only if tied to a new process and jurisdiction
Brand trademark	Potentially protectable, but does not prevent generic substitution
New delivery-system patents	Not identified for the legacy combination

When did ethynodiol diacetate and mestranol lose exclusivity?

The product lost effective exclusivity through a combination of patent expiry, generic competition, and therapeutic substitution. The exact date of final market exclusivity depends on the particular brand, strength, formulation, and jurisdiction.

For a legacy oral contraceptive, the economically important loss of exclusivity generally occurs when:

• The original patents expire.
• The FDA approves therapeutically equivalent generic products.
• Pharmacies and formularies substitute lower-cost alternatives.
• Prescribers migrate to newer products.
• The brand stops supporting promotion and distribution.

The combination’s exclusivity loss is historical rather than imminent. There is no current “patent cliff” comparable to that of a recently launched specialty drug.

How many patents currently cover ethynodiol diacetate and mestranol?

No meaningful number of live U.S. patents covering the legacy active-ingredient combination can be established from public regulatory information. The relevant distinction is between patents that once covered the product and patents that could still block commercial entry.

The practical answer is:

• Original product patents: expired.
• Current blocking patents on the legacy oral combination: none identified.
• Brand trademarks: potentially retained, but not a generic-entry barrier.
• New formulation or manufacturing patents: no commercially relevant estate identified.

The product therefore has a weak current patent position.

What is the Orange Book status of the product?

The Orange Book is organized by approved applications, products, applicants, dosage forms, and therapeutic-equivalence information. A legacy product may remain in historical regulatory records even if it is not actively marketed. The existence of an old approval does not establish current commercial availability.

The relevant Orange Book questions are:

1. Is the original reference-listed drug still marketed?
2. Are any therapeutically equivalent products currently listed?
3. Is the product identified as discontinued?
4. Are patents or regulatory exclusivities still listed?

For ethynodiol diacetate/mestranol, the commercial significance of any historical listing is limited. Even if the product appears in historical FDA records, an applicant would not face a modern Orange Book patent dispute comparable to a protected branded product.

Are there Paragraph IV challenges involving ethynodiol diacetate and mestranol?

No current, commercially significant Paragraph IV campaign is apparent for this legacy combination.

Paragraph IV litigation is most relevant when a generic applicant challenges an unexpired Orange Book-listed patent. That fact pattern is unlikely here because:

• The product is old.
• Original patents have expired.
• The branded commercial opportunity is limited.
• Market demand has shifted to other contraceptive formulations.
• A generic applicant would have limited economic incentive to incur substantial litigation costs.

Historical ANDA activity may exist, but it would not create a current investment thesis unless a company held an active, marketed product with a differentiated channel or geographic position.

What formulations are protected by ethynodiol diacetate and mestranol patents?

The historical product was an oral tablet supplied in a contraceptive regimen. The principal formulation distinction was the estrogen dose, particularly 35-microgram and 50-microgram mestranol presentations.

No current proprietary formulation advantage is evident. The formulation is technically straightforward compared with:

• Extended-release implants.
• Transdermal systems.
• Vaginal rings.
• Long-acting injectable contraceptives.
• Drug-device combination products.
• Hormonal intrauterine systems.

A new commercial entrant would therefore compete primarily on price, distribution, regulatory execution, and supply reliability rather than on formulation exclusivity.

What is the competitive landscape for this contraceptive?

Ethynodiol diacetate/mestranol competes in a mature market with significant substitution. The main competitive groups are:

Competitive group	Commercial position
Generic ethinyl estradiol/norethindrone tablets	Low-cost, broad pharmacy access
Generic ethinyl estradiol/levonorgestrel tablets	Strong formulary position
Drospirenone-containing pills	Branded and generic demand, differentiated tolerability profile
Progestin-only pills	Relevant where estrogen is contraindicated
Hormonal IUDs	Strong long-acting substitution
Etonogestrel implants	Long-acting substitution
Injectable contraception	Alternative adherence profile
Emergency contraception	Separate episodic market

The combination is disadvantaged by its legacy status and by mestranol’s limited use in contemporary prescribing. Newer oral contraceptives benefit from current clinical familiarity and more active commercial support.

What financial trajectory does the product have?

The financial trajectory is downward and largely complete.

Historical phase

The product generated revenue during the expansion of oral contraception and the growth of branded prescription products. Revenue would have depended on:

• Brand pricing.
• Prescription volume.
• Strength mix.
• Physician promotion.
• Pharmacy distribution.
• Insurance coverage.
• Generic substitution.

Mature phase

Revenue declined as newer products entered the market. The product’s high-dose 50-microgram estrogen presentation was particularly vulnerable to substitution because prescribing trends moved toward lower estrogen exposure where clinically appropriate.

Post-exclusivity phase

After patent and regulatory exclusivity ended, commercial value shifted from brand economics to low-margin generic supply. At that stage, the product required meaningful volume to support:

• Manufacturing.
• Quality control.
• Regulatory maintenance.
• Pharmacovigilance.
• Distribution.
• Inventory management.

Current phase

No reliable public source provides standalone current revenue for ethynodiol diacetate/mestranol. The combination is not generally reported as a material revenue contributor by major pharmaceutical companies. Its current financial profile is best classified as immaterial or negligible in the U.S. market.

What revenue exposure exists for manufacturers?

Revenue exposure depends on whether a company sells the legacy combination, supplies an active ingredient, or owns residual brand rights.

Stakeholder	Revenue exposure
Original brand owner	Likely negligible
Generic manufacturer	Low-volume, low-margin opportunity
Active pharmaceutical ingredient supplier	Limited and volume-dependent
Contract manufacturer	Possible niche demand
Distributor	Minimal relative to major contraceptive products
Pharmacy benefit manager	Limited product-specific impact
Investor portfolio	No material exposure unless concentrated in a niche market

A company could still generate localized revenue in selected international markets, but public product-level data are insufficient to quantify that opportunity. The product does not have the revenue characteristics of a current branded contraceptive franchise.

What manufacturing and intellectual-property barriers exist?

Manufacturing barriers are modest compared with modern complex products. The active ingredients are established small molecules, and the dosage form is a conventional oral tablet.

Potential barriers include:

• Reliable supply of ethynodiol diacetate and mestranol.
• Analytical testing for content uniformity and impurities.
• Stability data.
• Validation of the tablet manufacturing process.
• Regulatory requirements for combination products.
• Country-specific registration and labeling.
• Distribution economics at low annual volume.

The main barrier is commercial scale, not technology. If demand is low, manufacturers may discontinue the product because fixed regulatory and quality costs exceed achievable margin.

Is there biosimilar risk for ethynodiol diacetate and mestranol?

No. Biosimilars apply to biologic products, while ethynodiol diacetate and mestranol are small-molecule active ingredients. The relevant competitive threat is generic substitution, not biosimilar entry.

Which companies are challenging the product’s market position?

No current company-specific Paragraph IV challenge or litigation campaign is commercially significant for the legacy combination. Market displacement has occurred through broad therapeutic substitution rather than a single challenger.

The most relevant competitors are manufacturers of:

• Generic ethinyl estradiol/norethindrone products.
• Generic ethinyl estradiol/levonorgestrel products.
• Drospirenone-containing contraceptives.
• Long-acting reversible contraceptives.

These competitors do not need to challenge ethynodiol diacetate/mestranol patents. They compete through alternative products with stronger current demand.

What patent litigation and settlement agreements affect the product?

No active, material patent litigation or settlement agreement is identified for ethynodiol diacetate/mestranol. The product’s legal risk is principally historical.

A modern litigation event would be more likely to involve:

• A trademark dispute.
• A manufacturing or supply contract.
• A product-liability claim.
• A regulatory issue involving a specific country.
• A new formulation unrelated to the legacy tablet.

The absence of meaningful patent litigation reflects the product’s age and limited commercial value.

How does ethynodiol diacetate/mestranol compare with current oral contraceptives?

Attribute	Ethynodiol diacetate/mestranol	Current mainstream oral contraceptives
Estrogen component	Mestranol	Usually ethinyl estradiol or newer estrogen
Progestin	Ethynodiol diacetate	Multiple newer and established progestins
Market position	Legacy or discontinued	Active generic and branded markets
Patent position	Expired or exhausted	Product-specific; some newer products retain protection
Formulation differentiation	Limited	Wider range of regimens and delivery systems
Generic competition	Historical and likely extensive	Extensive for older products
Commercial growth	None apparent	Depends on product and channel
Litigation risk	Low	Higher for recently launched products
Biosimilar risk	None	None for small-molecule oral contraceptives

What generic launch scenarios exist?

Three scenarios are plausible:

Continued niche supply

A manufacturer maintains limited supply in a small geographic or institutional market. This would produce low revenue and depend on stable demand.

Re-entry after shortage

A company reintroduces the product if a market experiences supply shortages or if a distributor identifies an underserved niche. The opportunity would be operational rather than patent-driven.

Permanent commercial exit

The product remains unavailable because low volume, regulatory maintenance costs, and substitution by other contraceptives make production uneconomic. This is the most consistent scenario with the product’s current market position.

What is the geographic coverage of the product?

The product’s historical presence was strongest in markets where combined oral contraceptives were widely adopted and mestranol-containing products received regulatory approval. Current geographic availability is likely fragmented.

Country-level analysis would need to distinguish:

• Active marketing authorization.
• Actual commercial supply.
• Local generic registrations.
• Trademark ownership.
• National patent status.
• Public procurement demand.

U.S. market data do not establish current global availability. International niche supply should not be interpreted as evidence of a viable global franchise.

Key Takeaways

• Ethynodiol diacetate/mestranol is a legacy combined oral contraceptive.
• Demulen is the principal historical brand associated with the combination.
• Mestranol-containing products lost share to ethinyl estradiol formulations and other contraceptive technologies.
• Original composition and formulation patent protection has expired or lost practical commercial value.
• No significant current Paragraph IV challenge, patent litigation, settlement agreement, or biosimilar risk is apparent.
• The product has no identifiable current U.S. growth trajectory.
• Revenue is likely negligible and is not separately disclosed in standard public company reporting.
• Any remaining opportunity is a low-volume generic or geographic niche, not a protected branded franchise.
• Manufacturing complexity is modest, but low demand can make regulatory maintenance and supply uneconomic.
• The principal competitive threats are generic oral contraceptives and long-acting reversible contraception.

FAQs

Is ethynodiol diacetate/mestranol still sold in the United States?

It is not a significant actively marketed U.S. contraceptive product. Historical FDA approval records may remain even where commercial supply has ended or become limited.

Is Demulen still a protected brand?

Any remaining trademark rights would protect the brand name, not the underlying active-ingredient combination from generic competition. Patent-based exclusivity is no longer commercially meaningful.

Can a generic manufacturer launch ethynodiol diacetate/mestranol?

A manufacturer could pursue the applicable FDA regulatory pathway if a viable reference product and market opportunity exist. The principal obstacles would be commercial demand, supply economics, and regulatory maintenance rather than patent blocking rights.

Does mestranol provide a commercial advantage over ethinyl estradiol?

Mestranol has no evident current commercial advantage. Contemporary oral contraceptive prescribing generally favors products with established ethinyl estradiol or newer estrogen formulations and current market support.

Is ethynodiol diacetate/mestranol relevant to pharmaceutical investors?

Only as a legacy-product or niche-generic issue. It does not present the patent-expiry, pricing, or revenue-growth profile associated with a current branded pharmaceutical asset.

References

1. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations (44th ed.). Center for Drug Evaluation and Research.

2. U.S. Food and Drug Administration. (n.d.). Drug products discontinued from marketing. Center for Drug Evaluation and Research.

3. U.S. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/

4. U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application approvals. Center for Drug Evaluation and Research.

5. Centers for Disease Control and Prevention. (2024). U.S. selected practice recommendations for contraceptive use, 2024. U.S. Department of Health and Human Services.