List of Excipients in Branded Drug PROGESTERONE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Actavis Pharma Inc	PROGESTERONE	progesterone	0591-3128	BENZYL ALCOHOL
Actavis Pharma Inc	PROGESTERONE	progesterone	0591-3128	SESAME OIL
A-S Medication Solutions	PROGESTERONE	progesterone	50090-3240	D&C YELLOW NO. 10
A-S Medication Solutions	PROGESTERONE	progesterone	50090-3240	FD&C RED NO. 40
A-S Medication Solutions	PROGESTERONE	progesterone	50090-3240	GELATIN
A-S Medication Solutions	PROGESTERONE	progesterone	50090-3240	GLYCERIN

Generic Drugs Containing PROGESTERONE

Company	Ingredient	NDC	Excipient
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	D&C YELLOW NO. 10
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	FD&C RED NO. 40
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	GELATIN
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	GLYCERIN
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	LECITHIN, SOYBEAN
Hikma Pharmaceuticals USA Inc	progesterone	0054-0829	PEANUT OIL

What are the Most Frequently-Used Excipients in PROGESTERONE?

# Of NDCs	Excipient
2	AMMONIA
4	BENZYL ALCOHOL
1	CI 77499
15	D&C YELLOW NO. 10
8	FD&C RED NO. 40
7	FD&C YELLOW NO. 6

Progesterone Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

Progesterone has a fragmented dosage-form market spanning oral micronized capsules, vaginal gels, vaginal inserts, injectable oils, and compounded formulations. The central formulation problem is poor aqueous solubility combined with extensive first-pass metabolism. The strongest commercial opportunities are in peanut-free oral delivery, enhanced vaginal retention, preservative-free injectables, ready-to-use fertility products, and excipient systems that improve bioavailability without creating a new regulatory burden.

The most defensible excipient businesses will sell complete performance platforms rather than single commodity ingredients. Priority technologies include lipid-based solubilization, self-emulsifying drug-delivery systems, mucoadhesive vaginal polymers, low-irritation surfactant systems, and excipient-device combinations.

Why is progesterone difficult to formulate?

Progesterone is a poorly water-soluble steroid hormone. Oral administration is limited by dissolution and first-pass hepatic metabolism, while vaginal and injectable products face different problems involving retention, viscosity, tissue tolerability, sterility, and patient convenience.

Formulation challenge	Commercial consequence	Excipient response
Low aqueous solubility	Variable dissolution and absorption	Micronization, lipid vehicles, surfactants, self-emulsifying systems
Extensive first-pass metabolism	Higher oral dose and variable exposure	Lipid-based delivery, controlled release, alternative routes
Vaginal leakage	Reduced residence time and user dissatisfaction	Mucoadhesive polymers, in situ gels, bioadhesive inserts
Local irritation	Poor adherence and discontinuation	Low-surfactant systems, pH and osmolality control
Oil-based injection discomfort	Pain, inflammation and limited convenience	Alternative oils, viscosity optimization, depot systems
Peanut allergy risk	Restricted patient access and labeling burden	Peanut-free lipid vehicles
Sterility requirements	Higher manufacturing and container-closure costs	Ready-to-use sterile systems and robust packaging

The product design objective is not simply to dissolve progesterone. A commercially useful excipient system must preserve dose uniformity, improve exposure or residence time, remain manufacturable at scale, and avoid creating a new clinical or regulatory problem.

What progesterone dosage forms are commercially available?

The main U.S. product categories are oral micronized progesterone capsules, vaginal progesterone products and injectable progesterone in oil. FDA-approved products and generic equivalents differ materially in excipient requirements.

Oral micronized progesterone capsules

Prometrium was approved as an oral micronized progesterone capsule. The reference formulation uses progesterone in peanut oil within a soft gelatin capsule. Label-listed excipients include gelatin, glycerin, lecithin, mineral oil and titanium dioxide, with colorants varying by strength and manufacturer.[1]

Generic progesterone capsules have expanded the market. Most use micronized progesterone in a lipid vehicle, but the inactive ingredient profile can differ. That creates commercial space for:

• Peanut-free lipid vehicles
• Lower-viscosity fill systems
• Improved capsule shell stability
• Reduced oxidation in unsaturated oils
• Better content uniformity at low fill weights
• Excipient systems compatible with vegetarian or non-animal capsules

The primary technical risk is bioequivalence. A new lipid system must demonstrate that changes in solubilization, precipitation and gastrointestinal digestion do not produce clinically meaningful pharmacokinetic differences.

Vaginal gels

Vaginal progesterone gels use a polymeric aqueous or semisolid vehicle to deliver progesterone locally and systemically. The commercial value of the dosage form depends on retention, ease of application and predictable release rather than on solubility alone.

Key excipient categories include:

• Carbomer or polycarbophil-based polymers
• Humectants such as glycerin
• Mineral or vegetable oil phases
• Buffering agents
• Neutralizers
• Preservatives, where justified
• Applicator-compatible rheology modifiers

The major opportunity is a product that reduces leakage while maintaining acceptable spreadability. A gel that is too viscous can be difficult to dispense and may cause discomfort. A gel that is too fluid has poor retention and creates a perception of dose loss.

Vaginal inserts and tablets

Vaginal inserts, including progesterone tablet products, use solid excipients to control disintegration and release. Typical formulation functions include:

• Lactose or another soluble diluent
• Pregelatinized starch or other disintegrants
• Magnesium stearate as a lubricant
• Colloidal silicon dioxide as a flow aid
• Surfactants or wetting agents

The commercial opportunity is a smaller, less messy insert with consistent dissolution in the vaginal environment. Excipients that improve adhesion without delaying release excessively are particularly relevant.

Injectable progesterone in oil

Injectable progesterone is commonly formulated in an oil vehicle. Sesame oil is associated with established progesterone injection products, while other oil systems may be used in compounded or development-stage products. Benzyl alcohol may be present in some multidose products, although preservative-free presentations are commercially attractive.

The principal opportunities are:

• Peanut-free and sesame-free alternatives
• Reduced injection viscosity
• Lower injection volume
• Improved depot release
• Preservative-free single-dose presentations
• Compatible prefilled syringes
• Reduced crystallization during storage

Injectable progesterone requires close control of particle formation, viscosity, sterility, endotoxin, container compatibility and terminal or aseptic processing.

Which excipients offer the strongest progesterone opportunities?

Lipid-based solubilizers

Lipid excipients are the most commercially established approach for oral progesterone. Medium-chain triglycerides, long-chain triglycerides, mixed glycerides, phospholipids and surfactant-containing systems can increase apparent solubility and support intestinal absorption.

A high-value platform would provide:

1. Progesterone solubilization at commercially practical drug loading.
2. Limited precipitation after dilution in gastrointestinal fluid.
3. Consistent digestion and absorption across fed and fasted conditions.
4. Compatibility with hard or soft capsules.
5. Lower sensitivity to oxidation and temperature.
6. A peanut-free profile.

Self-emulsifying drug-delivery systems are technically attractive because they can form fine dispersions after contact with gastrointestinal fluid. Their risks include surfactant-related gastrointestinal effects, capsule-shell interaction, physical instability and the need for extensive in vitro and pharmacokinetic characterization.

Mucoadhesive vaginal polymers

Vaginal progesterone products need enough adhesion to resist leakage but not so much adhesion that removal, comfort or drug release is impaired. Polycarbophil, carbomer, cellulose derivatives, chitosan and selected polysaccharide systems can be evaluated.

The strongest formulation claims would relate to:

• Increased vaginal residence time
• Lower application frequency
• Reduced leakage
• Improved dose recovery
• Stable release across physiologic pH conditions
• Lower local irritation

Polymer selection also affects microbial compatibility, osmolality and the vaginal environment. A product that changes local conditions could face additional clinical scrutiny even if progesterone exposure is acceptable.

Low-irritation surfactant systems

Surfactants can improve wetting and dissolution, but excessive concentrations may cause burning, epithelial disruption or poor tolerability. Nonionic surfactants are generally more attractive than strongly irritating ionic systems, although each candidate requires route-specific testing.

A differentiated excipient supplier could commercialize a low-irritation surfactant blend with data on:

• Vaginal epithelial compatibility
• Cytotoxicity
• Microbial compatibility
• Progesterone solubilization
• Release performance
• Stability under accelerated conditions

Alternative injectable oils

An injectable oil can be differentiated through viscosity, tissue tolerability, oxidation resistance and supply reliability. Candidate vehicles must be pharmacopeial where possible and supported by parenteral-use precedent.

Potential positioning includes:

• Peanut-free progesterone injection
• Sesame-free progesterone injection
• Lower-viscosity fertility formulation
• Long-acting depot formulation
• Single-dose prefilled syringe product

The regulatory burden rises when the vehicle lacks broad injectable precedent or when the formulation changes the pharmacokinetic profile substantially.

What formulation patents protect progesterone products?

Progesterone itself is an old active ingredient, so composition-of-matter protection is generally unavailable. Commercial protection instead depends on formulation, route, delivery device, manufacturing process and method-of-use claims.

Patent category	Typical claim subject	Relative strength
Micronized oral capsule	Particle size, oil vehicle, capsule composition	Low to medium where generic products have established bioequivalence
Lipid-based oral system	Surfactant ratio, self-emulsifying composition, precipitation control	Medium if supported by distinctive pharmacokinetics
Vaginal gel	Polymer matrix, residence time, release profile	Medium
Vaginal insert	Excipients, disintegration, dose delivery and applicator	Medium
Injectable formulation	Oil vehicle, concentration, depot release, preservative profile	Medium to high if technically distinctive
Device combination	Applicator geometry, dose metering, prefilled delivery	Medium
Method of use	Fertility, luteal support, hormone therapy or pregnancy-related use	Variable and jurisdiction-dependent
Manufacturing process	Micronization, blending, encapsulation, sterilization	Medium if difficult to design around

FDA Orange Book listings should be reviewed product by product for current patents and regulatory exclusivity. Oral progesterone capsules have faced substantial generic competition, which limits the value of broad formulation claims that can be avoided through routine excipient substitution. Vaginal systems and specialized injectables generally offer stronger room for differentiated claims because performance depends on route-specific formulation behavior.[2]

What patent strategy is available for a new progesterone excipient system?

A new excipient platform should seek layered protection rather than rely on a single composition claim.

The strongest filing program would include:

• Composition claims covering excipient ranges
• Functional claims linked to dissolution or release
• Particle-size and drug-loading claims
• Stability claims
• Manufacturing claims
• Container-closure claims
• Applicator or prefilled-device claims
• Route-specific method-of-use claims
• Claims covering peanut-free or preservative-free status where technically meaningful

Patent strength depends on measurable performance. Claims tied only to the presence of familiar excipients are vulnerable to obviousness and design-around arguments. Claims supported by unexpected bioavailability, reduced variability, longer vaginal residence or improved injection tolerability are more defensible.

When does progesterone lose exclusivity?

Most early progesterone products have lost basic market exclusivity because progesterone is an established generic active ingredient. The commercial question is therefore not whether progesterone is off patent, but whether a specific dosage form has remaining regulatory or patent barriers.

Product type	General exclusivity position	Generic-entry risk
Oral micronized progesterone capsule	Mature generic market	High
Vaginal progesterone gel	More formulation-specific	Medium
Vaginal insert	Route and device dependent	Medium
Oil-based injection	Mature active ingredient, but manufacturing barriers remain	Medium
Novel depot injection	Potential formulation protection	Lower initially
Novel lipid-based oral capsule	Possible formulation and regulatory differentiation	Medium
Combination product	Depends on partner ingredient and labeling	Variable

FDA regulatory exclusivity differs from patent protection. A product can have no active patent barrier but still have limited competition if the formulation is difficult to reproduce, the reference product has limited commercial scale, or the route requires specialized clinical and CMC work.

What is the Orange Book and Paragraph IV risk for progesterone?

For oral progesterone capsules, Paragraph IV risk is generally less commercially important than ordinary generic substitution because multiple generic products and established formulation approaches exist. A new oral product would likely compete on manufacturing cost, supply reliability, capsule presentation, allergen profile or payer access.

For vaginal gels, vaginal inserts and novel injections, Paragraph IV challenges can have greater strategic importance. A generic applicant may challenge listed patents covering:

• Gel composition
• Polymer concentration
• Drug release
• Applicator configuration
• Dosing regimen
• Manufacturing process
• Stability characteristics

The litigation risk is highest when the reference product has meaningful sales and the listed patents cover formulation elements that are difficult to omit. Settlement agreements can delay launch, authorize an earlier entry date or permit entry under a license. The economic value of a settlement depends on the remaining patent term, product revenue, damages exposure and the number of potential generic entrants.

How strong is the progesterone patent estate?

The legacy progesterone patent estate is weaker than the estate for newer hormonal therapies because the active ingredient and many conventional dosage forms are old. The strongest new positions are likely to come from delivery performance.

Stronger patent positions

• A novel vaginal system with demonstrated residence-time improvement
• A peanut-free oral formulation with superior bioavailability or reduced variability
• A low-volume injectable depot with clinically meaningful duration
• A device-specific formulation that cannot be readily separated from the delivery system
• A formulation with improved stability under challenging storage conditions

Weaker patent positions

• Routine substitution of one conventional oil for another
• Broad claims covering progesterone plus standard capsule excipients
• Simple micronization without unexpected performance
• Generic polymer gels with conventional concentrations
• Use claims that overlap established progesterone indications

Patent owners should generate comparative data early. Dissolution, precipitation, pharmacokinetic variability, local tolerability, residence time and stability data are more valuable than formulation descriptions alone.

What FDA regulatory pathway applies to progesterone excipient products?

A generic version of an approved progesterone product may use the ANDA pathway if it matches the reference product in dosage form, strength, route and other applicable requirements. A materially different delivery system may require a 505(b)(2) application.

ANDA opportunities

An ANDA strategy is most suitable for:

• Oral micronized capsules
• Conventional vaginal inserts
• Established injectable presentations

The commercial advantages are lower development cost and reliance on the reference product’s safety and efficacy findings. The disadvantages are limited differentiation and intense price competition.

505(b)(2) opportunities

A 505(b)(2) strategy may be appropriate for:

• A new oral lipid system
• A sustained-release vaginal gel
• A novel injectable depot
• A new route or dosing schedule
• A formulation with a different excipient profile and clinical effect

The 505(b)(2) pathway can support differentiated labeling, but the sponsor must address formulation-specific safety, local tolerability and pharmacokinetic issues.

Compounded progesterone

Compounded progesterone remains relevant in fertility care and hormone therapy, particularly where commercial products do not meet a patient’s dosage, allergen or excipient requirements. However, compounded products face quality, sterility, potency and regulatory constraints. A commercial manufacturer can compete by offering standardized, peanut-free, preservative-free and ready-to-use presentations with validated quality controls.

Which companies and sectors offer commercial partnership opportunities?

The most relevant partners are not limited to progesterone manufacturers. Opportunities exist across the excipient, delivery-system, packaging and contract-manufacturing markets.

Partner category	Opportunity
Excipient manufacturers	Lipid vehicles, mucoadhesive polymers, surfactant systems
Capsule suppliers	Vegetarian shells, oxygen-barrier systems, low-permeability shells
Applicator manufacturers	Metered vaginal applicators and prefilled systems
CDMOs	Sterile oil filling, softgel encapsulation, semisolid manufacturing
Generic drug companies	ANDA-ready oral and vaginal products
Fertility-focused companies	Vaginal inserts, gels and injectable formulations
Hormone-therapy companies	Peanut-free oral capsules and patient-friendly delivery
Packaging companies	Light- and oxygen-protective container-closure systems

Licensing opportunities are strongest where an excipient platform can be transferred into multiple products. A polymer or lipid technology with data in progesterone may also be applicable to other poorly soluble steroids, reproductive hormones and local vaginal therapies.

What are the highest-value commercial opportunities?

1. Peanut-free oral progesterone

A peanut-free capsule addresses a clear patient and prescribing concern. The commercial product must maintain bioequivalence, capsule stability and acceptable manufacturing economics. The opportunity is larger in branded or specialty channels than in undifferentiated generic supply.

2. Vaginal progesterone with improved retention

A lower-leakage gel or insert could compete on patient experience and adherence. Supporting claims would require comparative data on residence time, leakage, tolerability and dose delivery.

3. Preservative-free injectable progesterone

A single-dose, ready-to-use product could address fertility-clinic workflow, preservative exposure and administration convenience. The main barriers are sterile manufacturing, container compatibility and economic production at relatively modest volumes.

4. Long-acting progesterone depot

A depot injection or implant could reduce administration frequency. This is a higher-risk opportunity because altered exposure may require substantial clinical development and could move the product beyond a simple generic or formulation strategy.

5. Excipient and device co-development

The combination of formulation and applicator design offers stronger differentiation than an excipient alone. A metered applicator can control dose, reduce handling and support method-of-use or device claims.

How does progesterone compare with other reproductive-health products?

Product attribute	Progesterone	Estradiol	Progestin products
Solubility challenge	High	Variable by form	Variable
First-pass concern	High for oral progesterone	Route-dependent	Often significant
Vaginal opportunity	Strong	Moderate	Moderate
Injectable opportunity	Established oil products	Less standardized	Product-specific
Generic competition	High for oral forms	High for many forms	High for older agents
Excipient differentiation	Strong	Strong in transdermal and vaginal systems	Strong in long-acting systems
Patent value	Mainly formulation and device	Formulation, device and method	Product-specific

Progesterone offers more room for excipient-driven differentiation than a simple mature oral tablet because the molecule has meaningful route and bioavailability constraints. Its commercial ceiling is limited by generic competition in established dosage forms.

What manufacturing and geographic barriers affect progesterone excipients?

Manufacturing barriers are highest for sterile injectables, softgel capsules and specialized vaginal products. Key controls include:

• Excipient purity and residual solvent limits
• Oxidation control for oils
• Particle-size distribution for micronized progesterone
• Blend uniformity
• Gel rheology
• Microbial limits
• Sterility and endotoxin
• Extractables and leachables
• Capsule-shell compatibility
• Applicator dose accuracy

Geographic opportunities differ by market. The U.S. favors ANDA and 505(b)(2) strategies tied to FDA precedent. Europe requires compliance with EU pharmaceutical legislation and excipient quality expectations, while fertility markets in Asia and Latin America may place greater value on clinic-ready vaginal and injectable presentations. Peanut-free and preservative-free positioning can be commercially relevant across regions, but local labeling and excipient restrictions must be assessed separately.

Key Takeaways

• Progesterone’s main formulation problems are poor water solubility, first-pass metabolism, vaginal leakage and injectable tolerability.
• Oral micronized capsules are commercially mature and face high generic competition.
• Peanut-free lipid systems offer the clearest oral excipient opportunity.
• Vaginal gels and inserts provide stronger room for differentiation through retention, comfort and controlled release.
• Preservative-free, low-viscosity injectable products can address fertility-clinic workflow and patient convenience.
• Patent value is concentrated in formulation, device, manufacturing and method-of-use claims, not the progesterone molecule.
• ANDA products offer lower development cost but limited differentiation. Novel delivery systems are better suited to 505(b)(2) development.
• The most defensible IP combines composition claims with measured improvements in bioavailability, retention, tolerability or stability.
• Excipient suppliers should commercialize validated platforms with regulatory data rather than commodity ingredients alone.

FAQs About Progesterone Excipient Commercial Strategy

Can progesterone be formulated without peanut oil?

Yes. Peanut-free systems can use alternative lipid vehicles, mixed glycerides, medium-chain triglycerides, phospholipids or self-emulsifying compositions. The formulation must still demonstrate acceptable bioequivalence, stability and capsule performance.

Which excipient is best for vaginal progesterone retention?

No single polymer is universally optimal. Polycarbophil, carbomer, cellulose derivatives and polysaccharide systems can improve adhesion, but selection depends on rheology, drug release, pH, osmolality and local tolerability.

Is micronized progesterone protected by patents?

The active ingredient is old, and conventional oral micronized progesterone products are generally exposed to generic competition. Current protection, where present, is more likely to involve formulation, device, manufacturing or method-of-use claims.

Does a new progesterone excipient require clinical trials?

The requirement depends on the regulatory pathway and the extent of formulation change. A conventional generic may rely primarily on pharmaceutical equivalence and bioequivalence. A novel route, depot system or clinically differentiated formulation may require additional clinical and local-tolerability studies.

What progesterone product has the greatest licensing potential?

A peanut-free oral system, a low-leakage vaginal delivery platform and a preservative-free injectable product have the strongest near-term licensing potential. A long-acting depot has greater upside but also materially higher clinical, manufacturing and regulatory risk.

References

1. U.S. Food and Drug Administration. (2023). Prometrium (progesterone) capsules: Prescribing information.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
3. U.S. Food and Drug Administration. (2024). Inactive ingredient database.
4. U.S. Food and Drug Administration. (2022). Guidance for industry: Bioequivalence studies with pharmacokinetic endpoints for drugs submitted under an ANDA.
5. U.S. Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary.
6. European Medicines Agency. (2015). Guideline on the pharmaceutical quality of inhalation and nasal products.
7. Amidon, G. L., Lennernäs, H., Shah, V. P., & Crison, J. R. (1995). A theoretical basis for a biopharmaceutic drug classification: The correlation of in vitro drug product dissolution and in vivo bioavailability. Pharmaceutical Research, 12(3), 413-420.