List of Excipients in Branded Drug LOESTRIN 24 FE

Loestrin 24 Fe Excipient Strategy and Commercial Opportunities

Last updated: September 5, 2026

Loestrin 24 Fe is a combined oral contraceptive containing norethindrone acetate and ethinyl estradiol in a 24-day active-tablet regimen, followed by four ferrous fumarate tablets. Its commercial value is concentrated in the complete dosage system: low-dose hormone tablets, iron-containing reminder tablets, color differentiation, packaging, and reliable 28-day adherence. Brand patent barriers have largely expired, leaving generic manufacturers, excipient suppliers, contract manufacturers, and combination-pack developers as the principal commercial beneficiaries.

What is Loestrin 24 Fe and how is it formulated?

Loestrin 24 Fe contains 1 mg of norethindrone acetate and 20 mcg of ethinyl estradiol per active tablet. Each blister pack contains 24 white active tablets and four brown tablets containing 75 mg of ferrous fumarate, equivalent to approximately 25 mg of elemental iron.[1]

Product attribute	Loestrin 24 Fe
Active hormones	Norethindrone acetate, ethinyl estradiol
Strength per active tablet	1 mg / 20 mcg
Regimen	24 active tablets followed by four iron tablets
Iron component	Ferrous fumarate, 75 mg per tablet
Dosage form	Immediate-release oral tablets
Pack structure	28-tablet cycle
Therapeutic category	Combined hormonal contraceptive
Reference product developer	Warner Chilcott, later associated with Actavis/Allergan
U.S. regulatory pathway	NDA-approved branded drug
Biosimilar relevance	None; this is a small-molecule product

The four brown tablets do not provide contraceptive hormone activity. They are intended to maintain daily tablet-taking behavior while providing iron during the withdrawal-bleeding interval. The iron tablets also create a product-identification and manufacturing requirement that does not exist for a conventional 21/7 oral contraceptive pack.

What excipients are used in Loestrin 24 Fe?

The formulation uses conventional tablet excipients selected for low-dose content uniformity, compression, disintegration, stability, and visual differentiation. Public product information identifies excipients including lactose monohydrate, microcrystalline cellulose, pregelatinized corn starch, magnesium stearate, and tablet colorants. The ferrous fumarate tablets use a separate excipient system suited to iron-containing tablets.[1,2]

Because inactive-ingredient listings can differ by tablet color, strength, supplier, and manufacturing site, generic developers must compare each proposed formulation against the FDA-approved reference product and the FDA Inactive Ingredient Database rather than assume that the white and brown tablets use the same composition.[3]

What is the excipient role in the active tablets?

The active tablets require:

• A diluent such as lactose monohydrate to support tablet mass at very low hormone loading.
• Microcrystalline cellulose to improve compactibility and tablet strength.
• Pregelatinized starch to assist binding and disintegration.
• Magnesium stearate as a lubricant.
• A color system for white active tablets and visual separation from the iron tablets.

The hormone dose is small relative to the tablet mass. Blend uniformity is therefore a central technical risk. Poor segregation control can produce assay variability even when the overall formulation composition is correct. Manufacturers need validated low-dose blending, controlled particle-size distributions, and robust sampling plans.

What is the excipient role in the ferrous fumarate tablets?

The brown tablets are chemically and functionally distinct from the active tablets. Ferrous fumarate has a high pigment and density contribution and can affect blend flow, tablet appearance, dissolution, and tooling wear. The iron tablets require:

• A binder and filler system that supports adequate hardness.
• A disintegrant that prevents excessive tablet persistence.
• Lubrication compatible with iron-containing blends.
• A brown color system that remains stable through shelf life.
• Packaging controls that limit moisture exposure and tablet abrasion.

Ferrous fumarate can also create compatibility and stability issues with certain excipients. Iron-containing formulations should be assessed for color migration, degradation products, metal-catalyzed oxidation, and interaction with coating components.

What patents protect Loestrin 24 Fe?

The principal U.S. patent barriers associated with Loestrin 24 Fe were historical Orange Book listings covering the contraceptive formulation and related product claims. The relevant patent protection has expired, eliminating the principal U.S. patent obstacle to abbreviated new drug application competition.[4]

Patent issue	Commercial assessment
Active ingredient patents	Expired or not a current barrier
Formulation patents	Historical protection; no meaningful current U.S. exclusivity barrier
Method-of-use patents	No current broad barrier to generic contraceptive use identified
Iron placebo-tablet design	Commercial know-how remains relevant, but it is not equivalent to active patent exclusivity
Packaging and tablet color	May support trade dress or product differentiation, subject to legal limits
Manufacturing process	Potentially protectable by process patents or trade secrets, but not a known barrier to routine generic entry

The Orange Book remains the controlling source for current listed patents and exclusivity. Patent status can vary by reference-product presentation and jurisdiction. A generic applicant must still conduct its own Orange Book review and Paragraph IV analysis for the applicable reference-listed drug.[4]

When did Loestrin 24 Fe lose exclusivity?

Loestrin 24 Fe lost practical U.S. market exclusivity after expiration of the relevant brand patent protection and the availability of generic approvals. The product was approved by FDA in 2006, and generic norethindrone acetate/ethinyl estradiol/ferrous fumarate products entered the U.S. market years later.[1,5]

Milestone	Approximate timing
Loestrin 24 Fe FDA approval	2006
Brand patent period	Primarily expired by the early 2020s
Generic development	Began before final patent expiry
Generic U.S. availability	Established by the 2010s
Current market structure	Generic-led, with limited brand relevance

The commercial opportunity is therefore not based on discovering an unserved patent-protected market. It is based on manufacturing efficiency, supply reliability, retail contracting, formulary access, and differentiated presentation.

What is the Orange Book status of Loestrin 24 Fe?

The Orange Book identifies the reference product and provides the legal framework for generic substitution and patent certifications. Loestrin 24 Fe is a small-molecule oral dosage form, so an ANDA applicant must demonstrate pharmaceutical equivalence and bioequivalence rather than conduct a biosimilar development program.[4,6]

The key regulatory considerations are:

1. The generic must match the active ingredients, strengths, dosage form, and route.
2. The active and iron tablets must be supplied in the correct 24-plus-four configuration.
3. Bioequivalence must be established for the hormone-containing tablets.
4. The inactive ingredients must be acceptable under FDA requirements.
5. Labeling must preserve clinically relevant administration instructions.
6. The proposed product must address any current Orange Book patents through Paragraph III or Paragraph IV certification.

Which companies are challenging or competing with Loestrin 24 Fe?

Competition has come primarily from generic manufacturers rather than from biosimilar developers. Companies active in generic oral contraceptives have included Teva, Mylan/Viatris, Lupin, Glenmark, Amneal, and other ANDA sponsors, depending on the specific product, strength, and period.

The principal competitive variables are:

Competitive variable	Effect on market position
Wholesale acquisition cost	Determines payer and pharmacy preference
Reliable 28-day packaging	Reduces substitution and fulfillment problems
Tablet appearance	Supports patient recognition and adherence
Ferrous fumarate supply	Can affect continuity of the complete pack
Hormone blend uniformity	Controls regulatory and product-quality risk
Retail and Medicaid contracts	Drives volume more than brand recognition
Manufacturing scale	Determines margin under generic pricing pressure

The product is relatively difficult to differentiate clinically because generic versions contain the same hormones and regimen. Differentiation is more feasible through supply continuity, packaging quality, customer service, and contract pricing.

What formulation patents and manufacturing barriers remain?

Expired active-product patents do not eliminate formulation and manufacturing barriers. They shift the source of competitive advantage from legal exclusivity to execution.

Low-dose hormone uniformity

Norethindrone acetate and ethinyl estradiol are present at low concentrations. A manufacturer must control:

• Drug-substance particle size.
• Premix dilution.
• Blend segregation.
• Sampling error.
• Compression-force variation.
• Tablet weight and assay uniformity.

A supplier that provides a validated premix or engineered excipient system could reduce development time for smaller ANDA sponsors.

Iron-tablet robustness

The ferrous fumarate tablets can create separate technical issues:

• Variable flow and density.
• Tablet friability.
• Tooling contamination.
• Color variability.
• Iron-related oxidation.
• Packaging and humidity sensitivity.

An excipient platform optimized for iron-containing oral solids could support both generic contraceptives and other iron-containing products.

Packaging and adherence design

Loestrin 24 Fe depends on correct sequencing. A commercial product should use calendarized blister packaging or another system that clearly identifies the 24 active tablets and four iron tablets. Unit-dose packaging, child-resistant secondary packaging, and high-contrast tablet labeling can support adherence and reduce dispensing errors.

What commercial opportunities exist for excipient suppliers?

The strongest excipient opportunities are formulation-enabling rather than patent-driven.

Direct excipient supply

Suppliers can target:

• Low-dose direct-compression systems.
• Lactose and microcrystalline cellulose grades with controlled particle size.
• Pregelatinized starch for binding and disintegration.
• Low-peroxide excipients for hormone stability.
• Lubricants with consistent surface-area characteristics.
• Iron-compatible color and coating systems.

The sales proposition is shorter development time, improved process capability, and lower batch-failure risk.

Ready-to-use premixes

A validated premix containing the hormone at a controlled dilution could reduce blend-uniformity risk. The commercial model could include technical-service support, process-transfer documentation, and quality agreements. Such products may generate recurring revenue from multiple generic manufacturers, although regulatory change-control requirements can make customers cautious about switching suppliers.

Specialized tablet coatings

Coatings can differentiate the active and iron tablets, improve swallowability, control dust, and stabilize color. A coating supplier may also provide a complete color-matching package for multiple manufacturing sites.

Packaging partnerships

A company that combines tablets, blister materials, serialization, and calendar packaging can offer a contract-manufacturing solution rather than a single excipient. This is attractive to smaller ANDA sponsors that lack integrated packaging capacity.

What licensing deals and settlement agreements affect the market?

No current licensing arrangement is required to manufacture a conventional generic version after expiration of the relevant U.S. patent barriers. Historical brand-generic settlements may have governed launch timing before patent expiry, but those agreements do not create a continuing commercial right for new entrants.

For a new supplier, the relevant agreements are more likely to be:

• Excipient supply and quality agreements.
• Contract manufacturing agreements.
• Technology-transfer licenses.
• Packaging and trademark licenses.
• Distribution contracts.
• Co-development agreements with ANDA sponsors.

Trade-secret licensing may be more valuable than patent licensing where a supplier has a validated premix, coating process, or packaging configuration.

What is the FDA regulatory status of generic Loestrin 24 Fe?

Generic versions are regulated through the ANDA pathway. The FDA evaluates pharmaceutical equivalence, bioequivalence, chemistry, manufacturing and controls, labeling, and facility compliance.[6]

The reference product’s four iron tablets do not create a separate therapeutic equivalence problem equivalent to the hormone tablets, but the applicant must still present the complete approved regimen accurately. A product that omits the iron tablets, changes the pack sequence, or uses an unclear presentation could create substitution, adherence, or labeling problems.

The FDA’s inactive-ingredient framework also limits formulation freedom. Excipients must be acceptable for the route and dosage form, and a novel level or new excipient may require additional justification.[3]

What generic entry risks exist?

Generic entry risks are operational rather than patent-centered.

Risk	Potential impact
Hormone blend nonuniformity	Batch rejection or regulatory deficiency
Ferrous fumarate supply disruption	Inability to release complete 28-day packs
Packaging errors	Recalls, medication errors, and retailer penalties
Color inconsistency	Product complaints and identification concerns
API price volatility	Margin compression
Multiple generic entrants	Rapid price erosion
Contract concentration	Loss of volume after one payer decision
Manufacturing-site changes	Supplements, comparability work, and launch delays

Generic manufacturers should also account for pharmacovigilance, labeling updates, product complaints, and supply-chain controls applicable to estrogen-containing contraceptives.

How does Loestrin 24 Fe compare with other oral contraceptives?

Loestrin 24 Fe differs from a standard 21/7 combined oral contraceptive in both regimen and product architecture.

Product architecture	Commercial implication
21 active tablets plus seven nonhormonal days	Simpler manufacture, no iron-tablet component
24 active tablets plus four iron tablets	More active-tablet days, differentiated packaging, iron-tablet supply requirement
24 active tablets plus four inert tablets	Similar adherence structure without ferrous fumarate complexity
Extended-cycle products	Fewer withdrawal intervals but different labeling and market positioning
Progestin-only products	Different safety profile, formulation, and patient segment

The 24/4 structure can support adherence-oriented positioning, but the iron component adds manufacturing cost and quality complexity without creating meaningful patent exclusivity.

What is the revenue exposure and market opportunity?

Brand revenue exposure is limited because Loestrin 24 Fe has been displaced by generic products and is not the primary growth vehicle for the original brand owner. The larger opportunity lies in recurring generic volume and enabling inputs.

Potential beneficiaries include:

• Generic ANDA sponsors.
• Hormone API suppliers.
• Ferrous fumarate suppliers.
• Direct-compression excipient manufacturers.
• Tablet-coating companies.
• Contract packagers.
• Specialty distributors.
• Payers seeking lower-cost contraceptive alternatives.

Margins are likely to depend on scale and supply reliability. A commodity excipient supplier faces price pressure. A supplier that combines low-dose premix technology, technical support, and packaging integration can capture more value.

How strong is the patent estate for Loestrin 24 Fe?

The current patent estate is weak as a barrier to U.S. generic entry because the important product patents are expired or no longer commercially determinative. The stronger protectable assets are process know-how, analytical methods, formulation development data, supplier qualification, and packaging execution.

A new entrant should not base its strategy on attempting to recreate brand exclusivity. It should focus on:

1. Cost-efficient tablet manufacture.
2. Consistent 28-day packaging.
3. Dual-source API and ferrous fumarate supply.
4. Robust low-dose blend control.
5. Differentiated customer service and order fulfillment.
6. Geographic filings where local rights or regulatory barriers remain relevant.

Key Takeaways

• Loestrin 24 Fe uses 24 hormone tablets followed by four ferrous fumarate tablets.
• The core formulation challenge is low-dose hormone uniformity, not novel drug delivery.
• The iron tablets create separate excipient, stability, color, and supply-chain requirements.
• U.S. patent barriers are largely historical and do not prevent conventional generic entry.
• No biosimilar pathway applies because the product contains small-molecule active ingredients.
• The strongest commercial opportunities are in generic manufacturing, premixes, specialized excipients, packaging, and supply reliability.
• Brand revenue exposure is limited; generic volume and formulation-enabling services are more relevant.
• Process know-how and integrated packaging can create commercial differentiation after patent expiry.

FAQs

Can ferrous fumarate be removed from a Loestrin 24 Fe generic?

Removing ferrous fumarate would change the product’s composition and could prevent the product from qualifying as pharmaceutically equivalent to the reference product. A separate 24/4 contraceptive without iron would require its own regulatory strategy.

Are the active and iron tablets required to use the same excipients?

No. The two tablet types have different compositions and functional requirements. Separate excipient systems are generally more appropriate for controlling hormone uniformity and iron-tablet performance.

Is Loestrin 24 Fe eligible for a biosimilar application?

No. Norethindrone acetate and ethinyl estradiol are small-molecule drugs. The relevant pathway is an ANDA, not a biologics license application or biosimilar application.

Can a generic manufacturer change the tablet color?

Changes to appearance may be possible, but they must comply with FDA requirements, labeling expectations, pharmaceutical-equivalence standards, and trade-dress restrictions. The active and iron tablets must remain clearly distinguishable.

What is the best commercial entry point for an excipient company?

A low-dose oral-solid premix combined with iron-compatible excipients, validated processing guidance, and blister-packaging support offers a stronger value proposition than supplying commodity lactose or microcrystalline cellulose alone.

References

1. U.S. Food and Drug Administration. (2006). Loestrin 24 Fe prescribing information.
2. DailyMed. (n.d.). Loestrin 24 Fe: Norethindrone acetate and ethinyl estradiol tablets; ferrous fumarate tablets. National Library of Medicine.
3. U.S. Food and Drug Administration. (n.d.). Inactive ingredient database.
4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.
5. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: Loestrin 24 Fe, NDA 021871.
6. U.S. Food and Drug Administration. (2015). Abbreviated new drug application process.