List of Excipients in Branded Drug AYGESTIN

Generic Drugs Containing AYGESTIN

Company	Ingredient	NDC	Excipient
Teva Women's Health LLC	norethindrone acetate	51285-424	ANHYDROUS LACTOSE
Teva Women's Health LLC	norethindrone acetate	51285-424	CELLULOSE, MICROCRYSTALLINE
Teva Women's Health LLC	norethindrone acetate	51285-424	MAGNESIUM STEARATE

What are the Most Frequently-Used Excipients in AYGESTIN?

# Of NDCs	Excipient
1	ANHYDROUS LACTOSE
1	CELLULOSE, MICROCRYSTALLINE
1	MAGNESIUM STEARATE

AYGESTIN Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

AYGESTIN is a legacy oral tablet containing norethindrone acetate, a synthetic progestin used for secondary amenorrhea, endometriosis, and abnormal uterine bleeding caused by hormonal imbalance. Its commercial opportunity is driven by generic substitution, supply reliability, formulation differentiation, and access to lower-cost or improved-dose products rather than by active brand exclusivity.

The most practical excipient strategy is a conventional immediate-release tablet using a robust filler-binder system, controlled disintegration, low-impact lubrication, and tightly managed impurity and dissolution profiles. Commercial value may come from improved manufacturability, smaller tablets, packaging stability, pediatric or geriatric usability, and alternative dosage forms.

What is AYGESTIN and what excipients does it use?

AYGESTIN contains norethindrone acetate, also known as norethisterone acetate in some markets. The marketed product is an oral 5 mg tablet. FDA labeling identifies inactive ingredients that generally include lactose monohydrate, starch, and magnesium stearate, with product-specific coloring and coating components depending on the manufacturer and presentation.[1]

Attribute	AYGESTIN profile
Active ingredient	Norethindrone acetate
Dosage form	Immediate-release oral tablet
Common strength	5 mg
Therapeutic class	Progestin
Indications	Secondary amenorrhea, endometriosis, abnormal uterine bleeding
Administration	Oral, cyclic or continuous regimens depending on indication
Reference product	AYGESTIN
Primary formulation opportunity	Generic immediate-release tablet
Main commercial constraint	Low-cost generic competition

Norethindrone acetate is a potent active at a relatively low tablet loading. The excipient system therefore has a major effect on tablet weight, blend uniformity, content uniformity, compression behavior, dissolution, and packaging economics.

The product does not require a complex delivery platform. A conventional tablet can meet the principal regulatory and commercial requirements if it demonstrates pharmaceutical equivalence, bioequivalence, acceptable dissolution, and consistent manufacturing performance.

What excipient functions are most important for norethindrone acetate tablets?

Excipient selection should prioritize content uniformity, dissolution reproducibility, tablet robustness, and low manufacturing cost.

Diluent and filler strategy

Lactose monohydrate is a logical starting point because it is compatible with conventional direct-compression or wet-granulation approaches and is already associated with the reference product’s formulation history.[1] Microcrystalline cellulose can improve compactability and reduce dependence on lactose, particularly where direct compression is preferred.

A practical filler strategy is:

Formulation objective	Candidate excipients	Commercial rationale
Low-cost conventional tablet	Lactose monohydrate, pregelatinized starch	Familiar supply chain and established regulatory history
Direct compression	Microcrystalline cellulose, spray-dried lactose	Improved flow and compression
Reduced lactose exposure	Microcrystalline cellulose, dibasic calcium phosphate	Supports lactose-free positioning
Smaller tablet	High-density fillers, optimized granulation	Reduces tablet volume while maintaining dose uniformity
Improved blend uniformity	Ordered-mixture or carrier-based approach	Helps manage low-dose API distribution

The active constitutes a small fraction of total tablet mass. Segregation risk can arise from differences in particle size, density, electrostatic behavior, and surface area between norethindrone acetate and the filler. Excipient particle engineering may be more commercially important than the choice between otherwise conventional fillers.

Binder and granulation strategy

Pregelatinized starch, povidone, or hydroxypropyl cellulose can support wet granulation and improve tablet strength. The binder level should remain low enough to avoid prolonged disintegration or slower dissolution.

Wet granulation can improve content uniformity and reduce segregation, but it increases process steps, equipment use, and development cost. Direct compression can reduce manufacturing cost but requires tighter control of particle-size distribution, flow, blend time, and segregation during transfer.

Disintegrant strategy

Croscarmellose sodium, sodium starch glycolate, and crospovidone are standard candidates. Crospovidone may be attractive where rapid wicking and low gelling behavior are desired. Croscarmellose sodium is widely used in immediate-release tablets and can provide reliable disintegration at relatively low levels.

For a low-dose steroid tablet, the disintegrant should be screened against dissolution rather than selected solely on disintegration time. Excessive compression force, hydrophobic lubrication, or over-granulation can delay drug release even when nominal disintegration remains acceptable.

Lubricant and glidant strategy

Magnesium stearate is historically consistent with AYGESTIN-type formulations, but its level and blending time require control. Over-lubrication can reduce tablet hardness, increase friability, and slow wetting or dissolution.

Colloidal silicon dioxide can improve flow and reduce sticking. Sodium stearyl fumarate is an alternative lubricant where magnesium-stearate sensitivity creates a dissolution or mechanical-performance issue. The substitution may require comparative dissolution, stability, and bioequivalence assessment.

What formulations are protected by AYGESTIN patents?

AYGESTIN is a legacy product with extensive generic competition. The original product and early formulation rights are not expected to provide a meaningful current barrier to conventional generic norethindrone acetate tablets.

A commercial review should distinguish among:

1. The active ingredient, norethindrone acetate.
2. The original immediate-release tablet.
3. Any later formulation or manufacturing patents.
4. Method-of-use patents.
5. Current Orange Book-listed patents, if any.
6. Third-party patents covering alternative dosage forms or excipient systems.

The commercial availability of multiple norethindrone acetate tablets indicates that the basic active ingredient and conventional tablet platform are open to generic competition. A product-specific patent search remains necessary before launch because third-party rights can arise around modified release, combination products, packaging, manufacturing processes, or new indications.

Does AYGESTIN have meaningful current exclusivity?

AYGESTIN has no commercially meaningful new-drug exclusivity barrier for a conventional generic 5 mg tablet. The product is an established small-molecule drug, and FDA-approved generic norethindrone acetate tablets are available in the United States.[2]

The principal market-access pathways are:

• Abbreviated New Drug Application approval.
• Section 505(b)(2) development for a materially different formulation or route.
• Full New Drug Application development for a new clinical profile or indication.
• Regional regulatory pathways outside the United States.

The relevant challenge is therefore formulation execution and market economics, not loss of a near-term exclusivity period.

What is the Orange Book status of AYGESTIN?

The Orange Book is the principal FDA source for listed drug patents, therapeutic-equivalence evaluations, and certain exclusivity information.[3] AYGESTIN is an established oral tablet product for which generic norethindrone acetate tablets have entered the market.

For a new generic applicant, the key Orange Book issues are:

Issue	Relevance to AYGESTIN
Reference listed drug	Identifies the product used for ANDA comparison
Therapeutic equivalence	Determines substitutability of approved generic tablets
Patent listings	Determines Paragraph IV or certification strategy
Exclusivity	Determines whether an ANDA can receive final approval
Product labeling	Establishes dosage, indications, warnings, and administration
Strength and dosage form	Controls the scope of the generic application

Because patent listings and regulatory records can change, any transaction, launch, or litigation decision should rely on the current FDA Orange Book and Drugs@FDA records rather than historical product databases.[2,3]

When does AYGESTIN lose exclusivity?

AYGESTIN’s practical market exclusivity has already ended. Generic norethindrone acetate tablets are marketed, and the active ingredient is not protected by a current composition-of-matter exclusivity period.

The relevant timing question is not when AYGESTIN loses exclusivity, but whether a new entrant can achieve adequate margins after accounting for:

• ANDA development costs.
• Bioequivalence and analytical testing.
• FDA review and potential deficiency cycles.
• Contract manufacturing costs.
• Wholesaler and pharmacy discounts.
• Market-share erosion after launch.
• Shortage-related supply opportunities.
• State substitution and payer contracting.

A new entrant should not assume that an old brand product creates a premium-price opportunity. The commercial case depends on differentiated supply, lower cost, improved packaging, or a formulation that reaches a segment underserved by current generics.

What Paragraph IV challenges affect AYGESTIN?

Paragraph IV certifications apply when an ANDA applicant asserts that a listed patent is invalid, unenforceable, or will not be infringed. For a legacy norethindrone acetate tablet, the likelihood of a commercially significant Paragraph IV dispute is lower than for a recently approved branded product.

The principal scenarios are:

• No listed patent requiring a Paragraph IV certification.
• Certification that listed patents have expired.
• Paragraph III certification with approval deferred until patent expiry.
• Paragraph IV certification against a later formulation or use patent.
• Litigation involving a narrow method-of-use patent rather than the core tablet.

A generic applicant should assess whether proposed labeling includes all branded indications. Carving out a patented method of use may be possible under the ANDA framework, but the carve-out must not create an impermissible gap in required labeling or undermine safe use of the remaining indications.[4]

What method-of-use patents could affect norethindrone acetate products?

The core AYGESTIN uses involve treatment of secondary amenorrhea, endometriosis, and abnormal uterine bleeding. New patents could theoretically cover:

• Specific dosing schedules.
• Combination hormonal regimens.
• Treatment of a newly defined patient population.
• Reduced adverse-effect protocols.
• Use with a device or diagnostic test.
• Alternative administration routes.
• New formulations with altered pharmacokinetics.

Such rights would not necessarily block a conventional generic tablet for all existing indications. The practical effect would depend on claim scope, labeling, patent listing, enforceability, and the applicant’s proposed indication set.

How strong is the AYGESTIN patent estate?

The core patent estate is weak as a barrier to conventional generic entry. AYGESTIN is an old small-molecule tablet with multiple generic competitors and no evident platform complexity comparable to a biologic, depot injection, transdermal system, or extended-release product.

Patent-estate factor	Assessment
Active ingredient patent	Expired or commercially non-blocking
Basic immediate-release tablet	Low barrier
Formulation complexity	Low to moderate
Device dependence	None for the standard tablet
Manufacturing complexity	Low to moderate
Bioequivalence burden	Manageable but sensitive to low-dose uniformity
Litigation risk	Lower than for recent branded products
Differentiation opportunity	Moderate through formulation, supply, packaging, or route

Manufacturing know-how can still matter. A process that consistently achieves low-dose content uniformity, acceptable dissolution, low impurity formation, and efficient compression may produce a cost advantage even without enforceable patent protection.

What commercial opportunities exist for AYGESTIN excipient innovation?

The strongest opportunities are incremental and operational.

Lactose-free or low-lactose tablets

A lactose-free formulation could address patients with lactose intolerance, excipient preferences, or institutional formulary requirements. The commercial benefit would depend on whether current generic products use lactose and whether payers or pharmacies recognize a meaningful distinction.

Microcrystalline cellulose, mannitol, dibasic calcium phosphate, and starch-based systems are potential alternatives. The formulation must maintain equivalent performance without increasing tablet size or manufacturing cost.

Smaller tablets

The 5 mg active load permits a relatively small tablet, but excipient density, compression behavior, and dose uniformity determine the final dimensions. A smaller tablet may improve swallowing and reduce packaging volume.

High-density fillers, optimized granulation, and reduced coating weight can support this objective. Tablet size alone is unlikely to justify a major price premium, but it can support a patient-centered product or private-label agreement.

Improved dissolution robustness

Dissolution variability can arise from lubricant overuse, API particle-size differences, hydrophobic excipients, or compression-force variation. A robust formulation that remains within specification across manufacturing lots may reduce batch failure risk.

Possible approaches include:

• Controlled API particle-size distribution.
• Shorter magnesium-stearate blending time.
• Use of sodium stearyl fumarate.
• Crospovidone-based disintegration.
• Wet granulation to reduce segregation.
• Standardized compression-force control.

Packaging and stability

Norethindrone acetate tablets should be evaluated for sensitivity to moisture, light, oxygen, and packaging interactions. High-barrier blister packaging or bottles with appropriate desiccant protection may support longer shelf life or distribution into humid markets.

Packaging can be a practical differentiator where the tablet itself is difficult to distinguish from competing generics. Calendar blister packs may also support cyclic dosing regimens, although they add packaging cost.

Alternative dosage forms

Potential 505(b)(2) opportunities include:

• Oral liquids or suspensions.
• Orally disintegrating tablets.
• Lower-dose tablets for titration.
• Combination products.
• Modified-release formulations.
• Vaginal or other localized delivery systems.

These products would face higher regulatory and clinical risk than a standard ANDA. A new dosage form may require additional pharmacokinetic, safety, stability, and labeling work. The commercial opportunity is greater where the product solves a clear administration or adherence problem.

How does AYGESTIN compare with competing progestin products?

AYGESTIN competes with generic norethindrone acetate tablets, other oral progestins, and hormonal products used for overlapping indications.

Product category	Active ingredient	Main advantage	Main limitation
AYGESTIN and generics	Norethindrone acetate	Established oral tablet and broad clinical familiarity	Commodity pricing
Medroxyprogesterone acetate	Medroxyprogesterone acetate	Broad availability and multiple dosage forms	Different tolerability and clinical profile
Micronized progesterone	Progesterone	Bioidentical positioning and menopausal use	Sedation, formulation and administration considerations
Norethindrone tablets	Norethindrone	Low-cost oral progestin option	Different active ingredient and dosing
Levonorgestrel products	Levonorgestrel	Strong contraceptive and device-based applications	Not a direct substitute for every AYGESTIN indication

The most direct competitor is generic norethindrone acetate. Therapeutic alternatives compete based on indication, dosing schedule, safety profile, prescriber familiarity, formulary treatment, and patient response.

Which companies are challenging AYGESTIN commercially?

The competitive field consists primarily of generic manufacturers and distributors offering norethindrone acetate tablets. Generic competition has historically included companies such as Teva, Mylan or Viatris, Amneal, Prasco, and other ANDA holders, subject to changes in product ownership and marketing status.[2]

The commercial market should be segmented by:

• Approved strength.
• Current marketing status.
• National versus regional supply.
• Authorized generic arrangements.
• Wholesaler inventory.
• Pharmacy substitution.
• Shortage history.
• Contract manufacturing dependence.

FDA approval does not establish continuous commercial availability. A product can remain approved while being discontinued, intermittently supplied, or limited to specific distributors. That distinction creates opportunity for reliable manufacturers with validated supply chains.

What generic launch risks exist for AYGESTIN?

A conventional generic launch has low patent risk but meaningful execution risk.

Regulatory risks

Key risks include:

• Failure to demonstrate bioequivalence.
• Dissolution differences from the reference product.
• Content-uniformity failures.
• Unacceptable impurities or degradation products.
• Inadequate stability data.
• Manufacturing-site deficiencies.
• Labeling differences.
• Incomplete indication carve-outs.

FDA guidance for orally administered immediate-release products emphasizes comparative dissolution, pharmacokinetic equivalence, and product quality controls.[5]

Manufacturing risks

The main manufacturing risks are segregation of the low-dose API, blend uniformity, sticking, over-lubrication, and lot-to-lot dissolution variation. These risks can be reduced through controlled particle-size specifications, validated blending, appropriate granulation, and in-process testing.

Commercial risks

Pricing pressure is likely because multiple generic suppliers can enter the market. A launch based solely on a lower unit price may produce limited returns. Better opportunities include shortage replacement, private-label supply, hospital and clinic contracts, and differentiated packaging or excipient positioning.

What licensing deals could support an AYGESTIN opportunity?

Licensing structures are more likely to involve supply, distribution, or formulation technology than core patent rights.

Potential deal models include:

1. Contract development and manufacturing for a generic ANDA holder.
2. Exclusive distribution of a lactose-free or patient-friendly formulation.
3. Technology licensing for direct compression or low-dose blending.
4. Private-label supply to pharmacy chains.
5. Regional licensing for markets where norethisterone acetate remains less commoditized.
6. Co-development of an alternative dosage form under a 505(b)(2) strategy.
7. Authorized-generic or brand-generic distribution arrangements.

The economic value of a deal depends on minimum purchase commitments, manufacturing redundancy, regulatory ownership, territory, transfer pricing, supply guarantees, and rights to formulation improvements.

What geographic markets offer the best opportunity?

The United States offers a mature but competitive generic market. The principal opportunity is reliable supply rather than exclusivity.

European and Commonwealth markets may use the name norethisterone acetate or norethisterone and may have different reference products, strength conventions, packaging requirements, and regulatory classifications. Latin American, Middle Eastern, and Asian markets may offer greater room for branded-generic positioning, but local registration and distribution rights are decisive.

Geographic expansion should account for:

• Product naming differences.
• Local pharmacopeial standards.
• Reference-product requirements.
• Import and serialization rules.
• Pharmacovigilance obligations.
• Local patent and data-exclusivity rules.
• Reimbursement and tender structures.
• Climate-zone stability requirements.

Key Takeaways

• AYGESTIN is a legacy norethindrone acetate 5 mg immediate-release tablet with no meaningful current exclusivity barrier to conventional generic entry.
• The strongest excipient platform is a conventional tablet using lactose, microcrystalline cellulose, starch, a superdisintegrant, and controlled lubrication.
• Low-dose content uniformity and dissolution control are more important than novel excipient selection.
• Lactose-free, smaller, better-packaged, or alternative-dose products offer the clearest incremental opportunities.
• Patent risk is lower than regulatory, manufacturing, supply, and pricing risk.
• A 505(b)(2) product could create more differentiation but would require materially greater development investment.
• Commercial value is most likely in reliable supply, private-label manufacturing, regional distribution, and patient-centered formulation improvements.

Frequently Asked Questions

Is AYGESTIN still patent protected?

The legacy AYGESTIN tablet is not protected by a commercially meaningful active-ingredient exclusivity period. Generic norethindrone acetate tablets are available.

Can a company launch a lactose-free generic AYGESTIN tablet?

Yes. A lactose-free formulation can be developed if it meets FDA requirements for pharmaceutical equivalence, bioequivalence, dissolution, stability, and labeling. It may require a different excipient composition and manufacturing process from the reference product.

Is norethindrone acetate difficult to formulate?

The tablet is technically manageable, but the low API loading creates risks involving blend uniformity, segregation, compression, and dissolution. Process control is more important than formulation novelty.

Would an orally disintegrating AYGESTIN product receive market exclusivity?

Not automatically. A new dosage form may qualify for regulatory protections only if it meets applicable statutory requirements. Its commercial differentiation would depend on the product claims, regulatory pathway, patent position, and clinical utility.

Is AYGESTIN a strong candidate for a 505(b)(2) product?

It may be suitable for a targeted 505(b)(2) strategy involving a new route, dosage form, dosing profile, or combination. The opportunity is stronger where the product addresses a documented administration or adherence problem that standard generic tablets do not solve.

References

1. U.S. Food and Drug Administration. (n.d.). AYGESTIN (norethindrone acetate) tablet prescribing information. DailyMed.
2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/
3. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations, 45th edition.
4. U.S. Food and Drug Administration. (2023). Abbreviated new drug application submissions: Refuse-to-receive standards.
5. U.S. Food and Drug Administration. (2024). Bioavailability and bioequivalence studies submitted in NDAs or INDs: General considerations.