List of Excipients in Branded Drug METHYLPREDNISOLONE ACETATE

Generic Drugs Containing METHYLPREDNISOLONE ACETATE

Company	Ingredient	NDC	Excipient
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0031	HYDROCHLORIC ACID
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0031	MIRIPIRIUM CHLORIDE
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0031	POLYETHYLENE GLYCOL 3350
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0031	SODIUM CHLORIDE
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0031	SODIUM HYDROXIDE
Teva Parenteral Medicines Inc	methylprednisolone acetate	0703-0043	BENZYL ALCOHOL

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

# Of NDCs	Excipient
14	BENZYL ALCOHOL
29	HYDROCHLORIC ACID
17	MIRIPIRIUM CHLORIDE
1	MYRISTYL-.GAMMA.-PICOLINIUM CHLORIDE
33	POLYETHYLENE GLYCOL 3350
14	POLYSORBATE 80

Last updated: September 24, 2026

Methylprednisolone acetate is an established corticosteroid injectable with limited remaining composition-of-matter patent value. Commercial opportunity is concentrated in excipient optimization, suspension stability, preservative-free packaging, device differentiation, manufacturing reliability, and route-specific products rather than in exclusivity from new chemical entity patents. The reference product, Depo-Medrol, is an injectable suspension containing methylprednisolone acetate, polyethylene glycol 3350, polysorbate 80, sodium chloride, and pH-adjusting agents. [1]

Methylprednisolone Acetate Excipient Strategy, Patent Position, and Commercial Opportunities

What is the current FDA status of methylprednisolone acetate?

Methylprednisolone acetate is a synthetic glucocorticoid approved for intramuscular, intra-articular, intrabursal, intralesional, and soft-tissue administration. Depo-Medrol is the principal U.S. reference product, marketed by Pfizer under NDA 011757. [1]

The drug is supplied as a sterile aqueous suspension rather than a solution because methylprednisolone acetate has low water solubility. Common strengths include 40 mg/mL and 80 mg/mL. The suspension is intended to provide prolonged local or systemic corticosteroid exposure after injection.

Methylprednisolone acetate is distinct from methylprednisolone sodium succinate, the water-soluble active used in products such as Solu-Medrol. The two products have different excipient systems, routes, reconstitution requirements, clinical uses, and manufacturing controls.

Regulatory status

Attribute	Methylprednisolone acetate
Active ingredient	Methylprednisolone acetate
Dosage form	Sterile injectable suspension
Common strengths	40 mg/mL and 80 mg/mL
Reference product	Depo-Medrol
Reference NDA	011757
Primary U.S. sponsor	Pfizer
FDA pathway for competitors	ANDA, where product requirements are met
Biologic classification	No
Biosimilar pathway	Not applicable
Main regulatory risks	Sterility, particle size, syringeability, resuspendability, dose uniformity, local tolerability, container closure

What excipients are used in methylprednisolone acetate injection?

The reference formulation uses polyethylene glycol 3350, polysorbate 80, sodium chloride, and pH-adjusting agents. Certain presentations and markets may differ in preservative status or packaging configuration, so the applicable FDA-approved labeling controls the commercial formulation. [1]

Functional role of the principal excipients

Excipient	Primary formulation function	Key development concern
Polyethylene glycol 3350	Vehicle and wetting component; supports suspension properties	Viscosity, injectability, oxidative or peroxide-related impurities
Polysorbate 80	Surfactant and wetting agent; reduces particle agglomeration	Peroxide formation, degradation, extractables, local tolerability
Sodium chloride	Tonicity adjustment	Osmolality and local injection-site tolerability
Hydrochloric acid or sodium hydroxide	pH adjustment	pH drift, container compatibility, precipitation
Water for injection	Continuous phase	Bioburden, endotoxin, dissolved oxygen, microbial control
Benzyl alcohol, where applicable	Preservative in multidose configurations	Neonatal toxicity, hypersensitivity, preservative-free positioning

The central formulation problem is maintaining a uniform, readily resuspendable suspension of hydrophobic steroid particles without increasing injection force or local irritation. A formulation that settles rapidly, forms a hard cake, or produces variable dose withdrawal can fail both clinical and commercial requirements.

What excipient strategy best supports a generic methylprednisolone acetate product?

The strongest strategy is usually a conservative reference-matched formulation with targeted improvement in physical stability and packaging. A substantially different excipient system can create additional clinical, immunogenicity, local-tolerability, or FDA comparability issues without creating meaningful patent value.

Particle engineering

Particle size distribution is a primary critical quality attribute. It affects:

• Sedimentation rate
• Resuspendability
• Needle passage
• Injection force
• Dose uniformity
• Duration of local drug exposure
• Risk of post-injection irritation

A narrow particle size distribution can improve dose consistency, but excessive micronization can increase surface energy and agglomeration. The development target should balance small particles with stable wetting and low aggregation.

Useful controls include laser diffraction, microscopy, sedimentation testing, redispersibility testing, and syringeability measurements. The product should be evaluated after accelerated and long-term storage, including repeated inversion and simulated shipping.

Surfactant selection

Polysorbate 80 is familiar to regulators and compatible with the reference product. Its main disadvantages are oxidation and degradation, which can generate peroxides and other impurities. A manufacturer considering an alternative surfactant would need to establish equivalent wetting, suspension stability, local tolerability, and extractables performance.

Potential commercial value exists in reducing surfactant concentration while preserving particle wetting. This may improve impurity control and local tolerability, but the change must be supported by comparative performance data.

Vehicle optimization

Polyethylene glycol 3350 contributes to the continuous phase and can affect viscosity. Higher viscosity can improve suspension behavior but increases injection force and may complicate administration through small-gauge needles.

Vehicle optimization should assess:

• Viscosity at refrigerated and room temperatures
• Injection force through intended needle sizes
• Resuspension after storage
• Sedimentation volume
• Dose withdrawal from vials
• Compatibility with polypropylene syringes and elastomeric closures

The commercial objective is not maximum viscosity. It is a practical balance between physical stability and administration performance.

Preservative-free design

A preservative-free presentation is a credible product-differentiation opportunity, especially for single-dose vials and prefilled syringes. It can reduce concerns involving benzyl alcohol exposure, hypersensitivity, and preservative-related local reactions.

The tradeoff is higher packaging and manufacturing cost. A preservative-free product also requires strict single-use labeling and container-closure controls. For institutional buyers, the value proposition depends on reduced waste, workflow efficiency, and preference for preservative-free injections.

What formulations are protected by methylprednisolone acetate patents?

The original composition-of-matter and early formulation rights for methylprednisolone acetate are historical and expired. The commercial value of the molecule is therefore based on manufacturing scale, regulatory approvals, supply reliability, and differentiated presentations rather than basic active-ingredient patent protection.

Potentially protectable subject matter in a new development could include:

• A defined particle-size distribution
• A specific surfactant-to-drug ratio
• A low-peroxide suspension system
• A preservative-free multidose alternative, if technically and legally supportable
• A prefilled syringe configuration
• A specific container-closure system
• A manufacturing process that limits agglomeration or improves sterility assurance
• A route-specific formulation with improved local tolerability
• A controlled-release depot system

Patentability would depend on unexpected technical results, claim scope, enablement, and prior art. Routine substitution of one pharmaceutically acceptable excipient for another is unlikely to produce a strong patent position without measured performance advantages.

Patent-strength assessment

Patent layer	Current commercial value	Assessment
Composition of matter	Minimal	Expired
Basic injectable suspension	Minimal to low	Mature technical field
Excipient combination	Low to moderate	Requires unexpected performance
Particle engineering	Moderate	Stronger if linked to measurable clinical or manufacturing benefit
Prefilled syringe or device	Moderate	Depends on device claims and freedom to operate
Manufacturing process	Moderate	Can protect know-how and process control
New depot delivery system	Moderate to high	Regulatory and clinical development burden is substantial
Method of use	Low	Broad corticosteroid uses are heavily established

When does methylprednisolone acetate lose exclusivity?

Methylprednisolone acetate has already lost its original market exclusivity. The reference product is a legacy small-molecule injectable, and generic competition is permitted through the ANDA pathway when applicants demonstrate pharmaceutical equivalence, bioequivalence where applicable, and compliance with applicable injectable-product requirements.

The product does not receive biosimilar exclusivity because it is not a biologic. No biosimilar risk analysis is required. The relevant competitive threat is generic injectable entry and substitution.

Orange Book status

The FDA Orange Book is the controlling source for current patent and exclusivity listings. For a legacy product such as Depo-Medrol, the commercial expectation is that any original exclusivity has expired and that remaining barriers, if any, would arise from product-specific regulatory requirements, manufacturing complexity, or later-listed patents rather than the original active ingredient. [2]

An applicant should separately review:

• Current Orange Book patent listings for the reference NDA
• Any active pediatric exclusivity
• Approved labeling differences
• Paragraph IV certifications
• Reference-product designation
• Product-specific bioequivalence requirements
• State substitution rules

Are there Paragraph IV challenges to methylprednisolone acetate?

Paragraph IV litigation risk appears structurally limited for a mature product with multiple approved or historically approved injectable competitors. Paragraph IV activity is most commercially relevant when a new ANDA applicant seeks to enter before an asserted listed patent expires.

For methylprednisolone acetate, the greater risk is often regulatory and manufacturing failure rather than a blocking patent. Relevant litigation triggers could include:

1. A newly listed formulation or device patent.
2. A patent covering a specific prefilled syringe or container closure.
3. A process patent asserted against a contract manufacturer.
4. A patent dispute involving a differentiated depot formulation.
5. A dispute over whether a proposed product is pharmaceutically equivalent to the reference suspension.

A generic applicant should not assume that an old active ingredient creates a zero-risk freedom-to-operate position. The practical review should cover patents owned by the reference sponsor, formulation developers, device manufacturers, and contract manufacturers.

What manufacturing and IP barriers affect commercial entry?

The principal barriers are technical execution and quality-system performance.

Manufacturing barriers

Methylprednisolone acetate suspension requires control over:

• Sterile micronization or sterile processing
• Particle-size distribution
• Aseptic filling
• Homogeneous suspension during filling
• Hold-time stability
• Mixing energy
• Bulk suspension settling
• Container closure integrity
• Visible and subvisible particles
• Endotoxin levels
• Shipping stability

Suspension uniformity during filling is particularly important. If the active settles during the filling operation, early and late units can contain different drug concentrations even when the bulk assay is within specification.

IP barriers

A company should assess freedom to operate around:

• Micronization equipment and process conditions
• Sterile milling
• Suspension-processing methods
• Prefilled syringe components
• Needle shields and elastomeric plungers
• Low-silicone or silicone-free systems
• Product-specific stability improvements
• Depot delivery technologies
• Contract manufacturing agreements

Trade secrets may be more valuable than patents for mixing sequence, sterilization parameters, bulk hold time, and filling controls. Those processes can be difficult for competitors to reconstruct from public filings.

What commercial opportunities exist for methylprednisolone acetate?

Preservative-free single-dose presentations

A preservative-free vial or prefilled syringe could command institutional preference where preservative exposure and administration efficiency matter. The opportunity is strongest in ambulatory surgery, pain clinics, orthopedic offices, and specialty injection settings.

Prefilled syringes

A prefilled syringe can reduce preparation steps, improve dose accuracy, and reduce vial waste. The development burden includes suspension stability in the syringe, plunger compatibility, needle selection, injection force, device integrity, and human-factors validation.

The product must remain readily resuspendable after storage. A prefilled syringe that requires vigorous manipulation or produces inconsistent dosing will lose its operational advantage.

Lower-waste packaging

Single-dose vials often generate unused residual volume. A lower-fill-volume presentation matched to common dosing patterns could improve procurement economics. Commercial value depends on the target procedure and whether the presentation reduces discarded drug.

Veterinary products

Veterinary corticosteroid use creates a separate market with different packaging, labeling, and regulatory requirements. Opportunities may exist in multidose vials, robust suspension systems, and species-specific presentations. Human and veterinary indications should not be combined without separate regulatory and quality assessments.

Contract manufacturing and private-label supply

Because the active ingredient is mature, reliable supply can be more valuable than a nominally novel formulation. A manufacturer with sterile suspension capacity, validated micronization, and consistent regulatory performance could supply private-label products to hospitals, specialty distributors, and regional pharmaceutical companies.

How does methylprednisolone acetate compare with competing corticosteroids?

Product	Active form	Solubility profile	Typical commercial positioning	Key distinction
Methylprednisolone acetate	Ester suspension	Poorly water-soluble	Depot and local injection	Prolonged suspension-based exposure
Methylprednisolone sodium succinate	Water-soluble salt	Freely soluble	Injectable systemic therapy	Rapid preparation and systemic use
Triamcinolone acetonide	Suspension	Poorly water-soluble	Intra-articular and local injection	Alternative depot corticosteroid
Dexamethasone sodium phosphate	Water-soluble salt	Freely soluble	Rapid systemic or local injection	Solution product with different potency and duration
Betamethasone acetate/phosphate	Mixed ester system	Suspension or dual-phase behavior	Local and systemic injection	Combination of soluble and depot fractions

Methylprednisolone acetate competes on duration, familiarity, and procedure-specific use. It is less competitive where rapid solubility, intravenous administration, or a low-viscosity solution is required.

What is the revenue exposure and market opportunity?

Public companies generally do not report standalone revenue for methylprednisolone acetate. Product-level revenue must be estimated from prescription, hospital purchasing, tender, and shipment data rather than company filings.

Revenue exposure is highest for manufacturers with:

• Multiple injectable corticosteroid products
• Hospital and ambulatory surgery contracts
• Established sterile manufacturing
• Broad distribution to orthopedic and pain practices
• A reliable supply position during injectable shortages
• Private-label or contract-manufacturing arrangements

The market is mature, so volume growth is likely to be modest. Margin expansion is more credible through manufacturing efficiency, reduced waste, differentiated packaging, and supply reliability than through price increases.

What is the strongest commercial and patent strategy?

The strongest strategy is a three-layer plan:

1. Use a reference-aligned suspension to minimize regulatory risk.
2. Differentiate through preservative-free packaging, prefilled delivery, or lower-waste presentation.
3. Protect manufacturing know-how and any measurable formulation improvement with targeted patents.

A broad excipient patent without demonstrated technical advantage is unlikely to create durable protection. A narrower claim tied to particle size, redispersibility, injection force, impurity control, or long-term stability has greater commercial relevance.

Key Takeaways

• Methylprednisolone acetate is a mature, genericized corticosteroid injectable.
• Its original composition-of-matter exclusivity has expired.
• The principal formulation challenge is maintaining a stable, uniform, readily injectable suspension.
• Polyethylene glycol 3350, polysorbate 80, sodium chloride, and pH adjusters form the reference excipient framework. [1]
• Preservative-free vials, prefilled syringes, lower-waste packaging, and reliable sterile supply are the clearest commercial opportunities.
• Biosimilar competition is irrelevant because methylprednisolone acetate is a small molecule.
• Paragraph IV risk is likely lower than manufacturing, sterility, suspension-uniformity, and container-closure risk.
• Patent value is most likely to arise from particle engineering, delivery devices, manufacturing processes, and technically differentiated depot systems.
• Public product-level revenue for methylprednisolone acetate is generally unavailable, requiring market-data estimation.

FAQs

Is methylprednisolone acetate the same as methylprednisolone sodium succinate?

No. Methylprednisolone acetate is a poorly water-soluble depot suspension. Methylprednisolone sodium succinate is a water-soluble injectable salt used where rapid preparation or systemic administration is required.

Can polysorbate 80 be removed from methylprednisolone acetate injection?

Removal may be technically possible, but the developer must demonstrate adequate wetting, suspension uniformity, redispersibility, stability, sterility, and local tolerability. The change may also affect the regulatory comparability strategy.

Is methylprednisolone acetate eligible for a biosimilar application?

No. It is a synthetic small molecule, so the relevant pathway is generally an ANDA or, for a materially different product, an NDA.

Can a prefilled syringe create new patent protection?

Yes. Patent protection may be available for a novel combination of suspension composition, syringe components, fill volume, needle system, stability profile, or administration characteristics. Routine placement of a known suspension in a conventional syringe is less likely to support strong claims.

What is the highest-value excipient innovation for this product?

The most commercially credible opportunity is a formulation that improves resuspendability and injection performance while reducing surfactant-related degradation or enabling a preservative-free, ready-to-use presentation.

References

1. U.S. Food and Drug Administration. (2024). Depo-Medrol (methylprednisolone acetate injectable suspension) prescribing information. Pfizer Inc.
2. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
3. U.S. Food and Drug Administration. (2024). Methylprednisolone acetate injectable suspension product information and labeling resources. FDA.
4. U.S. Pharmacopeia. (2024). United States Pharmacopeia and National Formulary: General chapters for sterile products, injections, and particulate matter. U.S. Pharmacopeial Convention.
5. U.S. Food and Drug Administration. (2024). Guidance for industry: ANDAs for certain highly purified synthetic peptide drug products that refer to listed drugs of recombinant origin. FDA.