List of Excipients in Branded Drug MEDROXYPROGESTERONE ACETATE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
PD-Rx Pharmaceuticals Inc	MEDROXYPROGESTERONE ACETATE	medroxyprogesterone acetate	43063-438	CALCIUM STEARATE
PD-Rx Pharmaceuticals Inc	MEDROXYPROGESTERONE ACETATE	medroxyprogesterone acetate	43063-438	LACTOSE
PD-Rx Pharmaceuticals Inc	MEDROXYPROGESTERONE ACETATE	medroxyprogesterone acetate	43063-438	MINERAL OIL

Generic Drugs Containing MEDROXYPROGESTERONE ACETATE

Company	Ingredient	NDC	Excipient
Amphastar Pharmaceuticals Inc	medroxyprogesterone acetate	0548-5400	HYDROCHLORIC ACID
Amphastar Pharmaceuticals Inc	medroxyprogesterone acetate	0548-5400	METHYLPARABEN
Amphastar Pharmaceuticals Inc	medroxyprogesterone acetate	0548-5400	POLYETHYLENE GLYCOL 3350

What are the Most Frequently-Used Excipients in MEDROXYPROGESTERONE ACETATE?

# Of NDCs	Excipient
29	CROSPOVIDONE
20	HYDROCHLORIC ACID
29	LACTOSE MONOHYDRATE

Last updated: August 2, 2026

Executive summary: Medroxyprogesterone acetate (MPA) is a mature, off-patent progestin with limited small-molecule exclusivity risk and meaningful formulation opportunities. The strongest commercial positions are long-acting injectable suspensions, preservative-free or low-preservative presentations, subcutaneous self-administration, device-enabled packaging, and differentiated oral products. Excipient selection must control particle aggregation, syringeability, depot release, sterility, preservative exposure, and long-term physical stability. Generic entry is established for oral tablets and intramuscular suspensions, while development barriers remain higher for ready-to-use subcutaneous products and device presentations.

Medroxyprogesterone Acetate Excipient Strategy and Commercial Opportunities

What is medroxyprogesterone acetate used for?

Medroxyprogesterone acetate is a synthetic progestin used in contraceptive injections, abnormal uterine bleeding, secondary amenorrhea, endometriosis-related pain, and selected hormone-dependent conditions. Its principal commercial formulations are:

Product type	Representative strength	Route	Commercial role
Oral tablet	2.5 mg, 5 mg, 10 mg	Oral	Mature generic market
Depot injection	150 mg/mL	Intramuscular	Long-acting contraception
Low-volume injection	104 mg/0.65 mL	Subcutaneous	Self-administration and simplified delivery
Compounded or specialty formulations	Variable	Oral, injectable, topical or other	Limited and jurisdiction-dependent

Pfizer’s Depo-Provera CI is an intramuscular aqueous suspension containing 150 mg of MPA per mL. Depo-subQ Provera 104 contains 104 mg of MPA in 0.65 mL for subcutaneous injection. Oral medroxyprogesterone acetate tablets are available from multiple generic manufacturers [1-4].

MPA is a small molecule, not a biologic. Biosimilar substitution is therefore irrelevant. The competitive framework is based on abbreviated new drug applications, formulation equivalence, manufacturing capability, device usability, supply reliability and pricing.

What excipients are used in medroxyprogesterone acetate injections?

The reference depot injection uses a relatively simple aqueous suspension system. Public labeling identifies polyethylene glycol 3350, polysorbate 80, sodium chloride, methylparaben and water for injection as inactive ingredients in the 150 mg/mL product [1].

Core excipient functions

Excipient	Functional purpose	Principal development concern
Polyethylene glycol 3350	Vehicle modification, wetting and suspension support	Viscosity, injection force and particle interaction
Polysorbate 80	Wetting and interfacial stabilization	Oxidation, hydrolysis, peroxide formation and particle-surface effects
Sodium chloride	Tonicity adjustment	Osmolality and compatibility
Methylparaben	Antimicrobial preservation	Hypersensitivity, regulatory limits and preservative exposure
Water for injection	Continuous phase	Sterility, endotoxin control and container compatibility

The excipient system is not interchangeable across routes. An excipient that is acceptable in an intramuscular depot may create unacceptable pain, irritation, viscosity or injection-force characteristics in a subcutaneous product. The development target must be defined by route, needle gauge, delivery volume, storage condition and intended administration setting.

Oral tablet excipients

Oral MPA tablets generally use conventional solid-dose excipients such as lactose or other fillers, starch-based disintegrants, lubricants and coating materials. Exact compositions vary by manufacturer and strength. The principal commercial opportunity is not a novel excipient alone. It is a differentiated tablet platform with improved swallowability, lower pill burden, modified release, lower excipient burden or combination therapy.

Which excipient properties control depot injection performance?

The critical quality attributes are particle-size distribution, crystal form, suspension uniformity, redispersibility, syringeability, delivered dose, sedimentation rate, sterility and chemical stability.

Particle engineering

MPA is administered as a crystalline suspension rather than as a fully dissolved drug. Particle size affects:

• Sedimentation and caking
• Needle passage
• Injection force
• Local tissue exposure
• Dissolution and depot persistence
• Dose uniformity after storage

A smaller particle size can improve suspension uniformity but may increase surface energy, aggregation and dissolution rate. A broader or poorly controlled distribution can produce inconsistent injection force and dose delivery. Particle engineering is therefore a primary formulation-control strategy.

Surfactant selection

Polysorbate 80 supports wetting and dispersion, but its degradation products can affect product quality. Development programs should measure peroxide content, hydrolytic degradation, subvisible particles and interactions with the MPA crystal surface. Alternative surfactants may create a differentiation opportunity, but a change from the reference system can complicate bioequivalence and inactive-ingredient justification.

Viscosity and injection force

Polyethylene glycol 3350 modifies the continuous phase and helps maintain suspension properties. Excess viscosity can impair administration through a narrow needle, especially for self-injection. Commercially viable products must balance:

• Physical stability
• Low sedimentation
• Rapid redispersion
• Acceptable injection force
• Limited injection-site discomfort
• Compatibility with prefilled syringes or autoinjectors

A high-viscosity formulation may perform well in a vial but fail in a prefilled syringe or wearable injector.

Preservative strategy

Methylparaben supports multidose-container control but creates a potential differentiation point. Preservative-free single-dose products can reduce preservative exposure and may appeal to patients or institutional buyers. The tradeoff is higher unit cost, greater packaging requirements and tighter aseptic-process controls.

A preservative-free product must be evaluated as a complete container-closure and administration system. The value proposition is strongest where single-dose packaging, self-administration or injection-site tolerability justifies the added cost.

What formulations are protected by medroxyprogesterone acetate patents?

The active ingredient is mature and broadly off-patent. The original composition and use patents associated with MPA and early depot products have expired or have limited practical relevance to current generic entry. Commercial protection now depends mainly on formulation, manufacturing, device and regulatory execution.

Protection category	Current strategic relevance
MPA molecule patents	Low; historical protection has expired
Conventional oral tablets	Low patent barrier; generic competition is established
Conventional 150 mg/mL IM suspension	Moderate technical barrier, low molecule-level exclusivity
Subcutaneous 104 mg/0.65 mL product	Higher formulation and device complexity
Prefilled syringe or autoinjector	Potential device and combination-product protection
Particle-engineered suspension	Potential process and formulation claims
New therapeutic indication	Possible method-of-use protection, subject to patentability and written-description requirements
Manufacturing process	Potential trade-secret and process-patent value

The strongest intellectual-property position would generally combine composition claims, particle-size or crystal-form claims, manufacturing-process claims, container-closure claims and device claims. A formulation patent that covers only a conventional excipient substitution may have limited blocking power if competitors can design around it.

When does medroxyprogesterone acetate lose exclusivity?

MPA has already lost core small-molecule exclusivity in the United States. Oral tablets and intramuscular depot products have long been subject to generic competition. No biosimilar pathway applies.

The relevant exclusivity analysis is product-specific:

Product	Exclusivity position	Entry assessment
Oral MPA tablets	Mature generic market	Low technical and legal entry barrier
150 mg/mL IM suspension	Established generic market	Formulation, manufacturing and quality barriers
104 mg/0.65 mL SC presentation	More specialized	Device, presentation and bioequivalence complexity
New combination or modified-release product	Potentially new protection	Dependent on formulation, indication and clinical evidence

FDA regulatory exclusivity can arise for a new formulation, new indication or eligible clinical development program, but the age of the active ingredient does not itself create current exclusivity. Any commercial assessment should distinguish FDA exclusivity from patent term. The Orange Book records patents and exclusivity by listed drug, not by active ingredient in the abstract [5].

What is the Orange Book status of medroxyprogesterone acetate?

The Orange Book is relevant for FDA-approved MPA products, particularly branded oral and injectable presentations. Patent listings, expiration dates and exclusivity codes must be reviewed at the product level because different strengths, routes, sponsors and formulations can have different records [5].

For a conventional generic MPA product, the main pathway is an ANDA with a Paragraph III certification where relevant patents have expired, or a Paragraph IV certification if an applicant asserts that a listed patent is invalid, unenforceable or not infringed. Paragraph IV litigation risk is generally lower for old conventional MPA products than for newer branded products with active formulation or device patents.

Paragraph IV challenge risk

A Paragraph IV strategy may be commercially useful where:

• A listed patent covers a narrow formulation feature.
• The applicant has a credible non-infringement position.
• The reference product has meaningful remaining revenue.
• The applicant can achieve 180-day generic exclusivity or another launch advantage.
• The formulation can be manufactured at scale without losing equivalence.

For mature oral MPA tablets, the commercial value of a Paragraph IV challenge is likely limited by existing generic competition. For a specialized subcutaneous product, the value depends on market size, device substitutability and whether the listed patent covers the formulation, device or method of use.

How strong is the patent estate for medroxyprogesterone acetate?

The patent estate is stronger around product execution than around the molecule itself.

Stronger protection areas

• Specific depot particle-size distributions
• Crystal-form or polymorph control
• Suspension stabilization systems
• Low-volume subcutaneous presentations
• Prefilled syringe configurations
• Autoinjector or wearable-injector integration
• Manufacturing processes that produce consistent redispersibility
• Container-closure systems that protect against surfactant or preservative degradation
• New uses supported by clinical data

Weaker protection areas

• Conventional oral tablets using standard excipients
• Broad claims to MPA alone
• Simple substitution of one common filler or lubricant
• Generic aqueous suspensions without a defined technical limitation
• Method claims that merely restate established contraceptive or gynecologic uses

Trade secrets may be more valuable than patents for milling conditions, wetting order, homogenization parameters, hold times, filling controls and suspension-aging specifications. These controls can determine whether a competitor can reproduce the product at commercial scale.

What commercial opportunities exist for MPA excipients and formulations?

1. Preservative-free single-dose injections

A preservative-free presentation could target patients with preservative sensitivity concerns, clinics seeking simplified administration and self-injection programs. The main commercial constraints are packaging cost, aseptic manufacturing and the need to prevent dose loss or misuse.

2. Low-injection-force subcutaneous products

The subcutaneous product has a lower dose volume than the 150 mg/mL intramuscular presentation. Further improvements could focus on:

• Reduced injection force
• Smaller needle gauges
• Faster administration
• Improved redispersion
• Reduced injection-site pain
• Compatibility with autoinjectors

The excipient strategy should not increase viscosity beyond the capability of the delivery device.

3. Ready-to-use prefilled syringes

Prefilled syringes can reduce preparation steps and medication errors. Development must address suspension settling during storage, needle clogging, silicone-oil interaction, extractables and leachables, and dose recovery from the syringe dead space.

4. Improved depot duration

A longer-acting injection could have commercial value if it reduces administration frequency. The technical approach may involve particle engineering, depot-forming excipients or alternative delivery systems. Such products would likely require more extensive clinical and pharmacokinetic work than a standard generic suspension.

5. Oral modified-release products

Modified-release MPA could target reduced dosing frequency or steadier exposure. The opportunity is clinically dependent because the active ingredient has established oral dosing options. A modified-release product must show a meaningful pharmacokinetic or adherence benefit, not only a different excipient profile.

6. Combination products

MPA combinations with estrogens or other hormonal agents could address specific therapeutic or contraceptive segments. Combination products face formulation compatibility, dose-ratio, clinical-risk and patent scrutiny. A new combination can generate its own patent estate, but it also creates more complex regulatory and pharmacovigilance obligations.

Which companies are challenging medroxyprogesterone acetate products?

Generic competition exists across oral and injectable MPA products. Companies active in generic hormonal products have included manufacturers such as Teva Pharmaceutical Industries, Sandoz, Prasco and other FDA-approved ANDA holders, depending on product, strength and time period. Pfizer remains associated with the Depo-Provera and Depo-subQ Provera reference products in the United States [1-3].

The competitive threat differs by presentation:

Segment	Competitive intensity	Differentiation opportunity
Oral tablets	High	Low-cost supply, packaging, combination products
IM suspension	Moderate to high	Supply reliability, vial or syringe presentation
SC suspension	Lower than tablets	Device integration, self-administration and usability
Novel depot system	Potentially lower	Duration, tolerability and adherence

What FDA regulatory pathway applies to new MPA formulations?

A conventional generic product normally uses the ANDA pathway and must demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug. Complex injectable suspensions may require more extensive characterization than simple immediate-release tablets.

A new MPA formulation with a distinct clinical profile may require a 505(b)(2) application. This pathway may be relevant to:

• New route of administration
• New dosage form
• Extended duration
• New delivery device
• New indication
• Reformulated product with reliance on existing knowledge and new supporting data

FDA’s product-specific guidance and inactive-ingredient databases are important development references. The database can identify prior use of excipients by route and dosage form, but it does not replace formulation-specific safety and quality assessment [6-7].

What manufacturing and IP barriers affect generic launch?

The most important barriers are operational rather than molecule-based.

Manufacturing barriers

• Reproducible particle-size control
• Prevention of caking during storage
• Sterile suspension processing
• Consistent filling of high-concentration suspensions
• Uniform dose withdrawal from vials
• Needle and syringe compatibility
• Control of surfactant degradation
• Stability under temperature excursions
• Scale-up without altered sedimentation or injection force

Intellectual-property barriers

• Formulation patents
• Device patents
• Process patents
• Method-of-use patents
• Container-closure patents
• Regulatory exclusivity for a newer presentation

A product may be legally launchable but commercially unattractive if its manufacturing yield is low, its injection force is high or its stability profile requires expensive cold-chain controls.

What patent litigation affects medroxyprogesterone acetate?

MPA is not generally characterized by the active patent litigation profile associated with newer high-value branded drugs. The principal litigation risk for a new generic would arise from any currently listed product-specific patents, Paragraph IV certification, device-related claims or method-of-use claims in the relevant jurisdiction.

Settlement agreements should be analyzed for entry dates, supply restrictions, authorized-generic provisions, covenants not to sue and any restrictions applying only to a particular dosage form. A settlement involving an oral product may not resolve risk for a subcutaneous injectable, and a formulation settlement may not cover device claims.

How does medroxyprogesterone acetate compare with competing contraceptive products?

Product	Delivery profile	Key commercial advantage	Excipient or formulation opportunity
MPA IM injection	Long-acting, clinic administered	Established efficacy and low dosing frequency	Stable suspension, low injection force
MPA SC injection	Lower-volume, potential self-administration	Convenience and reduced clinic dependence	Device compatibility and tolerability
Levonorgestrel implant	Long-acting implant	Multi-year duration	Polymer matrix and insertion system
Etonogestrel implant	Long-acting implant	Extended duration	Implant polymer and release control
Oral progestins	Daily oral dosing	Low manufacturing complexity	Modified release and combination products
Combined hormonal products	Oral, transdermal or vaginal	Broader contraceptive choices	Adhesion, permeation and release systems

MPA’s primary advantage is established depot delivery. Its disadvantages include injection-site effects, administration burden and the need to manage suspension quality. A formulation that improves convenience or reduces injection discomfort could capture value even without extending patent protection on the active ingredient.

What revenue exposure and launch scenarios apply?

Revenue exposure is concentrated in long-acting products rather than low-priced oral tablets. A generic launch scenario can be assessed through four variables:

1. Reference-product sales and market share.
2. Number of approved generic competitors.
3. Ability to substitute by route and presentation.
4. Manufacturing cost and supply reliability.

Likely launch scenarios

Scenario	Market effect
Additional oral tablet supplier	Price erosion with limited unit-growth opportunity
Additional IM suspension supplier	Moderate price pressure and supply diversification
SC generic without device differentiation	Regulatory and substitution complexity
Improved prefilled or autoinjector product	Potential premium pricing and channel expansion
Longer-acting or better-tolerated depot	New-product economics, but higher clinical cost

A supplier of pharmaceutical-grade polyethylene glycol, surfactant, preservative or suspension-processing technology can participate without owning the finished product. The most defensible value proposition is a validated excipient platform that improves redispersion, injection force, stability or device compatibility across multiple injectable products.

Key Takeaways

• Medroxyprogesterone acetate is a mature, off-patent small molecule with no biosimilar pathway.
• Oral tablet competition is intense and largely price-driven.
• Injectable suspensions have higher technical barriers because particle size, redispersibility, viscosity and sterility directly affect product performance.
• Polyethylene glycol 3350, polysorbate 80, sodium chloride, methylparaben and water for injection form the public-label excipient framework for the reference IM product.
• Preservative-free single-dose systems, prefilled syringes, autoinjectors and lower-injection-force formulations offer the clearest commercial opportunities.
• Patent value is concentrated in formulation, device, process and method-of-use claims rather than the MPA molecule.
• Paragraph IV risk is presentation-specific and more relevant to specialized injectable products than to mature oral tablets.
• Manufacturing know-how may provide stronger practical protection than broad formulation patents.
• The main launch risks are complex injectable equivalence, device compatibility, scale-up, supply reliability and pricing pressure.

FAQs

Can polyethylene glycol 3350 be replaced in a generic MPA injection?

Yes, but the replacement must support equivalent suspension performance, safety, sterility, injection characteristics and regulatory acceptability. A substitute can alter viscosity, sedimentation, particle aggregation and dose delivery.

Is methylparaben necessary in medroxyprogesterone acetate injections?

Not necessarily. Its use depends on the container format and microbial-control strategy. A single-dose preservative-free product may avoid methylparaben but requires suitable aseptic processing and packaging.

Is Depo-Provera protected by active U.S. patents?

The MPA molecule and original product protections are mature. Any current risk must be assessed against product-specific Orange Book listings, device claims, formulation patents and regulatory exclusivity.

Can a new MPA autoinjector receive patent protection?

Yes. Patentable subject matter may include the injector mechanism, suspension delivery controls, needle configuration, container system, administration sequence and formulation-device combination, subject to claim scope and prior-art analysis.

Is a new MPA depot formulation eligible for a 505(b)(2) application?

Potentially. A materially different dosage form, route, delivery system, release profile or indication may support a 505(b)(2) strategy, but the required clinical and pharmacokinetic evidence depends on the proposed product and reliance position.

References

1. Pfizer Laboratories. (2023). Depo-Provera CI medroxyprogesterone acetate injectable suspension prescribing information. U.S. Food and Drug Administration labeling database.

2. Pfizer Laboratories. (2023). Depo-subQ Provera 104 medroxyprogesterone acetate injectable suspension prescribing information. U.S. Food and Drug Administration labeling database.

3. U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs, medroxyprogesterone acetate products. https://www.accessdata.fda.gov/scripts/cder/daf/

4. DailyMed. (2024). Medroxyprogesterone acetate tablets: labeling and inactive ingredients. National Library of Medicine. https://dailymed.nlm.nih.gov/

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

6. U.S. Food and Drug Administration. (2024). Inactive Ingredient Database. https://www.accessdata.fda.gov/scripts/cder/iig/

7. U.S. Food and Drug Administration. (2024). Guidance for industry: ANDAs for certain highly purified synthetic peptides and complex drug products. U.S. Department of Health and Human Services.