List of Excipients in Branded Drug LEUPROLIDE ACETATE

Generic Drugs Containing LEUPROLIDE ACETATE

Company	Ingredient	NDC	Excipient
Eon Labs Inc	leuprolide acetate	0185-7400	ACETIC ACID
Eon Labs Inc	leuprolide acetate	0185-7400	BENZYL ALCOHOL
Eon Labs Inc	leuprolide acetate	0185-7400	SODIUM CHLORIDE
Eon Labs Inc	leuprolide acetate	0185-7400	SODIUM HYDROXIDE

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

# Of NDCs	Excipient
2	ACETIC ACID
2	BENZYL ALCOHOL
2	SODIUM CHLORIDE
2	SODIUM HYDROXIDE

Leuprolide Acetate Excipient Strategy and Commercial Opportunities

Last updated: August 23, 2026

Leuprolide acetate is a peptide gonadotropin-releasing hormone agonist whose commercial value depends on sustained-release delivery rather than the active ingredient alone. The main excipient platforms are biodegradable PLGA microspheres and in situ forming PLGA/N-methyl-2-pyrrolidone systems. The strongest opportunities are in long-acting depot formulation, solvent substitution, prefilled delivery systems, pediatric dosing, manufacturing yield, and differentiated release profiles.

What excipients are used in leuprolide acetate products?

Approved leuprolide products use excipients to control peptide release, maintain suspension or depot integrity, and support reconstitution or injection.

Product	Active ingredient	Delivery format	Principal excipient platform	Commercial sponsor
Lupron Depot	Leuprolide acetate	Injectable microspheres	Biodegradable lactic/glycolic acid copolymer system; product-specific diluent excipients	AbbVie
Eligard	Leuprolide acetate	In situ forming depot	50:50 poly(DL-lactic-co-glycolic acid) and N-methyl-2-pyrrolidone, or NMP	Tolmar
Fensolvi	Leuprolide acetate	Six-month injectable depot	PLGA/NMP polymeric delivery system	Tolmar
Lupron Injection	Leuprolide acetate	Immediate-release injection	Aqueous injectable formulation with conventional pH and tonicity control	AbbVie
Camcevi	Leuprolide mesylate	Six-month depot	ATRIGEL-type PLGA/NMP system	Accord BioPharma/Tolmar-related technology

Lupron Depot uses a microsphere technology in which the polymer matrix gradually hydrolyzes and releases leuprolide. Eligard and Fensolvi use a dual-syringe or prefilled delivery architecture in which the polymer solution forms a depot after administration. The FDA labels identify the polymeric delivery system for Eligard and Fensolvi as a combination of PLGA and NMP.[1,2]

Which excipients are most important technically?

The principal excipients are:

• PLGA, which controls degradation and drug diffusion.
• NMP, which acts as a water-miscible solvent and supports in situ depot formation.
• Mannitol, used in some lyophilized or microsphere presentations as a bulking or tonicity-supporting agent.
• Carboxymethylcellulose sodium, used in certain diluent systems to improve suspension behavior.
• Polysorbate 80, used in selected diluents or injectable systems to support dispersion.
• Water for injection, used as the reconstitution vehicle.
• Gelatin or related structural excipients, where present in specific microsphere presentations.

Exact excipient composition is product-specific and can vary by strength, dosage form, manufacturing process, and presentation. The commercial opportunity lies in controlling the interaction between polymer grade, solvent, peptide loading, particle size, and injection device.

How does the leuprolide acetate depot formulation work?

PLGA depots release leuprolide through a combination of water penetration, polymer hydrolysis, pore formation, and drug diffusion. The release profile is sensitive to both formulation composition and manufacturing conditions.

PLGA selection

PLGA is available in different lactide-to-glycolide ratios, molecular weights, end-group chemistries, and residual monomer profiles. A 50:50 PLGA grade generally degrades faster than higher-lactide compositions because glycolide increases hydrophilicity and water uptake.

Key formulation variables include:

Variable	Effect on product performance
Lactide:glycolide ratio	Changes polymer degradation rate
Molecular weight	Affects depot persistence, viscosity, and release duration
Acid- or ester-terminated polymer	Changes water uptake and local microenvironment
Polymer concentration	Influences injectability and depot volume
Peptide loading	Affects burst release and total dose
Particle size	Controls surface area and release kinetics
Residual solvent	Affects safety, stability, and syringe compatibility
Polymer porosity	Influences diffusion and initial burst
Moisture content	Can accelerate PLGA degradation during storage

The main technical risk is an excessive initial burst followed by an under-release phase. A commercial formulation must maintain pharmacokinetic exposure over one, three, four, or six months while preserving dose uniformity between batches.

NMP and in situ depot formation

NMP is used in Eligard and Fensolvi-type delivery systems because it dissolves or disperses PLGA and permits injection through a relatively small needle. After administration, water enters the formulation, NMP diffuses outward, and PLGA precipitates into a semisolid depot.

NMP creates several development constraints:

• Local tolerability at the injection site.
• Viscosity at refrigerated and room temperatures.
• Syringe force and needle gauge.
• Polymer precipitation rate.
• Risk of phase separation.
• Extractables and leachables from the delivery system.
• Compatibility with elastomers, adhesives, and syringe components.

A reformulation that reduces NMP while retaining depot integrity could create a meaningful product advantage. Candidate solvent systems include alternative water-miscible organic solvents, solvent blends, or lower-solvent formulations using higher-solids PLGA. Each alternative requires extensive evaluation of local tolerance, polymer precipitation, peptide stability, and device performance.

What formulation patents protect leuprolide acetate products?

The highest-value intellectual property generally protects the delivery system rather than the leuprolide molecule. Leuprolide acetate itself is an established peptide, and composition-of-matter protection is no longer the principal commercial barrier.

Patent categories

Leuprolide depot patent estates can cover:

1. PLGA microsphere composition.
2. Polymer molecular weight and lactide:glycolide ratio.
3. Peptide-to-polymer loading.
4. Particle-size distribution.
5. In situ forming depot systems.
6. NMP-containing polymer solutions.
7. Dual-syringe mixing systems.
8. Prefilled syringe configurations.
9. Reconstitution procedures.
10. Injection-device components.
11. Treatment regimens and dosing intervals.
12. Manufacturing and drying processes.

The most defensible claims are typically combination claims that connect a particular leuprolide dose with a polymer system, release profile, administration interval, and device configuration. Broad claims to PLGA or NMP alone are less commercially differentiated because those excipients have extensive prior-art use.

How strong is the excipient patent estate?

The estate is strongest where the sponsor controls multiple layers:

• Formulation composition.
• Depot manufacturing process.
• Device and presentation.
• Clinical dosing interval.
• Method-of-use claim.
• Manufacturing scale-up know-how.

A competitor may avoid a composition patent but still face process or device patents. Conversely, a generic or follow-on applicant may design around an excipient claim by changing PLGA grade, solvent concentration, polymer ratio, particle morphology, or presentation.

Patent strength is therefore product-specific. The active ingredient provides limited protection, while the formulation-device combination can create the practical barrier to entry.

When does leuprolide acetate lose exclusivity?

Leuprolide acetate products have largely moved beyond their original molecule-level exclusivity periods. The relevant commercial question is whether an applicant can obtain approval with an alternative depot formulation and avoid remaining formulation, process, method-of-use, or device patents.

Exclusivity layer	Relevance to leuprolide acetate
Compound patent	Generally historical and no longer the main barrier
FDA new-drug exclusivity	Historical for original products
Pediatric exclusivity	May have extended selected listed patents or regulatory exclusivity
Formulation patents	Can remain relevant for depot systems
Device patents	Relevant to prefilled syringes and dual-chamber presentations
Method-of-use patents	May affect indications such as prostate cancer or central precocious puberty
Orphan exclusivity	Product- and indication-specific; not a universal barrier
Regulatory exclusivity for a new product	Can apply to newer strengths, delivery systems, or indications

The applicable expiration dates must be determined from the current FDA Orange Book, individual patent records, and litigation history. Product-level exclusivity cannot be inferred from the age of the leuprolide molecule alone.[3]

What is the FDA regulatory status of leuprolide acetate products?

FDA-approved leuprolide products cover oncology, gynecology, and pediatric endocrinology.

Product	Key approved use areas	Dosing interval
Lupron Depot	Advanced prostate cancer; endometriosis; uterine leiomyomata, depending on presentation	Monthly to extended intervals
Eligard	Advanced prostate cancer	One, three, four, or six months, depending on strength
Fensolvi	Central precocious puberty	Six months
Lupron Injection	Prostate cancer and other approved indications depending on presentation	Immediate-release dosing

Eligard and Fensolvi are particularly relevant to excipient strategy because the polymeric delivery system is central to the product’s clinical utility. Fensolvi’s six-month pediatric schedule reduces injection frequency, but it also imposes a high requirement for dose reproducibility and local tolerability.[2]

Are biosimilars a risk for leuprolide acetate?

Traditional biosimilar competition is not the main risk because leuprolide acetate is a synthetic peptide drug rather than a biologic approved through the BLA pathway. Competition is more likely to arise through:

• ANDA-based generic injections.
• 505(b)(2) products using different depot technologies.
• Follow-on long-acting formulations.
• Authorized or licensed manufacturing arrangements.
• Products using leuprolide mesylate or another salt form.
• Device-led reformulations with equivalent clinical outcomes.

The regulatory pathway depends on the reference product, formulation differences, route of administration, dosage form, and extent of clinical bridging required. A materially different depot system may require clinical pharmacology or clinical efficacy work beyond a conventional generic package.

Which companies are challenging the leuprolide acetate market?

The competitive landscape includes originator products, long-acting depot specialists, peptide manufacturers, contract development and manufacturing organizations, and companies pursuing alternative androgen-deprivation therapies.

Key commercial players

• AbbVie, through the Lupron franchise.
• Tolmar, through Eligard and Fensolvi.
• Accord BioPharma, through oncology commercialization activities including Camcevi.
• Generic injectable manufacturers, subject to product-specific FDA approvals and patent certifications.
• CDMOs with PLGA microsphere, aseptic fill-finish, and prefilled syringe capabilities.
• Developers of competing androgen-deprivation products, including degarelix and oral GnRH antagonists.

The principal competitive axis is no longer simply monthly versus three-month dosing. It includes injection frequency, administration setting, needle size, reconstitution complexity, room-temperature handling, injection-site reactions, pharmacy economics, and payer coverage.

What commercial opportunities exist in leuprolide acetate excipients?

1. Lower-NMP depot systems

NMP reduction is the clearest excipient opportunity. A successful system could improve local tolerability, reduce solvent burden, and support a more differentiated safety profile. The technical challenge is maintaining polymer precipitation and drug release after reducing the solvent fraction.

Potential approaches include:

• Higher-solids PLGA formulations.
• Alternative biocompatible water-miscible solvents.
• Solvent blends with lower local irritancy.
• In situ gels based on thermoresponsive or phase-inverting polymers.
• Hybrid systems combining microspheres with injectable gels.

2. Improved PLGA grades

Specialty PLGA with controlled molecular weight distribution, low residual monomer, or tailored end groups can improve batch consistency. Excipient suppliers could differentiate through pharmaceutical-grade polymer portfolios with:

• Narrow molecular-weight distribution.
• Controlled acid value.
• Low endotoxin burden.
• Defined residual solvent limits.
• Consistent degradation kinetics.
• Regulatory documentation suitable for global filings.

3. Ready-to-use presentations

Dual-syringe reconstitution creates preparation steps and increases administration variability. A stable prefilled syringe, cartridge, or dual-chamber autoinjector could reduce preparation time and support administration in outpatient or primary-care settings.

The commercial value depends on:

• Polymer stability in the device.
• Reliable mixing or activation.
• Injection force.
• Needle protection.
• Shelf-life at refrigerated and room temperatures.
• Human-factors validation.
• Compatibility with pharmacy distribution.

4. Pediatric delivery systems

Fensolvi demonstrates the value of a six-month leuprolide acetate product for central precocious puberty. Further opportunities include smaller injection volumes, lower injection force, reduced injection-site pain, and devices designed for pediatric use.

A pediatric reformulation must preserve endocrine suppression while addressing patient and caregiver acceptance. The formulation, device, and administration method can support separate patent claims even when the active ingredient is established.

5. Manufacturing and yield improvements

PLGA microsphere manufacturing can involve emulsification, solvent removal, particle classification, drying, aseptic processing, and sterility assurance. Scale-up risk is substantial because small changes in mixing energy, temperature, solvent removal, or drying conditions can change release kinetics.

Commercial opportunities include:

• Continuous or semi-continuous microsphere production.
• Improved encapsulation yield.
• Reduced residual solvent.
• Closed aseptic processing.
• In-line particle-size monitoring.
• More efficient lyophilization.
• Process analytical technology for release control.
• Lower-cost sterile fill-finish.

Manufacturing know-how can remain commercially valuable even where patent protection is weak.

What generic entry risks exist for leuprolide acetate?

Generic entry risk differs by product.

Product type	Generic entry risk	Main barrier
Immediate-release leuprolide injection	Higher	Established aqueous injectable technology
Monthly microsphere depot	Moderate	Microsphere equivalence and release matching
Three- or four-month depot	Moderate to lower	Long-duration pharmacokinetic equivalence
Six-month PLGA/NMP depot	Lower near term than simple injection	Complex formulation, device, and clinical bridging
Pediatric six-month product	Moderate	Indication, device, dosing, and pediatric evidence
Prefilled or dual-syringe system	Moderate	Combination-product and device requirements

Paragraph IV challenges are possible where an applicant certifies that listed patents are invalid, unenforceable, or not infringed. The commercial impact depends on the Orange Book listing, the timing of the certification, the sponsor’s litigation response, and any 30-month stay under the Hatch-Waxman framework.[4]

A generic applicant may also pursue a non-infringing route using a different polymer composition or delivery format. That approach can reduce patent exposure but increase development cost and regulatory uncertainty.

What patent litigation and settlement issues affect the market?

Litigation risk is concentrated in three areas:

1. Whether a polymer-solvent combination falls within formulation claims.
2. Whether a device presentation infringes syringe or mixing-system claims.
3. Whether a proposed dosing interval infringes method-of-use claims.

Settlement agreements may include delayed launch dates, licenses, authorized-generic arrangements, or restrictions limited to particular strengths and indications. The commercial effect can differ by product because oncology, gynecology, and pediatric indications have different reimbursement and prescribing dynamics.

A patent review should separate:

• Orange Book-listed patents.
• Unlisted manufacturing patents.
• Device patents.
• Expired patents with continuing technical relevance.
• Pending applications.
• Patent term extensions.
• Pediatric extensions.
• Litigation outcomes and settlement licenses.

How does leuprolide acetate compare with competing androgen-deprivation drugs?

Attribute	Leuprolide acetate	Degarelix	Relugolix
Mechanism	GnRH agonist	GnRH antagonist	Oral GnRH antagonist
Onset profile	Initial testosterone flare can occur	Rapid suppression without classic flare	Rapid suppression without classic flare
Delivery	Injectable depot or injection	Injectable depot	Oral tablet
Excipient opportunity	PLGA, NMP, microspheres, devices	Injectable depot and formulation	Tablet excipients and oral absorption
Administration burden	Monthly to six-month intervals	Typically monthly	Daily oral dosing
Main commercial advantage	Long dosing intervals and established use	No initial flare	Oral administration
Main formulation risk	Release control and injection tolerability	Depot tolerability and administration	Adherence and daily dosing

Leuprolide retains value where long dosing intervals, clinical familiarity, and established reimbursement outweigh the disadvantages of depot injection. Oral GnRH antagonists create pressure in patients who prioritize rapid testosterone suppression or avoidance of injections.

What is the revenue exposure for leuprolide acetate manufacturers?

Revenue exposure is concentrated in long-acting depot products rather than immediate-release injections. Extended-duration products generally have higher formulation complexity and can support stronger pricing, but they also face greater technical and regulatory barriers.

The main revenue risks are:

• Generic or 505(b)(2) entry.
• Payer pressure on depot pricing.
• Conversion to oral GnRH antagonists.
• Loss of preferred formulary status.
• Manufacturing interruptions.
• Injection-site tolerability concerns.
• Device supply constraints.
• Patent settlement launches.

The strongest defense is a differentiated product with a long dosing interval, reliable administration, low preparation burden, and a defensible formulation-device estate.

Key Takeaways

• Leuprolide acetate commercial protection is centered on depot delivery, not the mature peptide itself.
• PLGA is the core excipient platform for microsphere and in situ forming depots.
• NMP enables injectable PLGA depot formation but creates opportunities for solvent reduction or substitution.
• Prefilled and dual-chamber devices can add commercial value and patent protection.
• Fensolvi illustrates the value of a six-month pediatric formulation.
• Generic entry is easier for immediate-release injections than for long-acting microsphere or in situ depot products.
• Excipient suppliers can capture value through specialty PLGA, process control, low-residual-solvent systems, and device-compatible formulations.
• The most durable patent estates combine formulation, manufacturing, device, and method-of-use claims.
• Biosimilar competition is less relevant than ANDA and 505(b)(2) competition.
• Commercial exposure is highest in extended-release depot products with meaningful reimbursement and administration advantages.

FAQs

Can leuprolide acetate be formulated without PLGA?

Yes. Alternative systems could include other biodegradable polymers, injectable gels, implants, nanoparticles, or lipid-based depots. The replacement must match the required release interval, peptide stability, local tolerability, sterility, and regulatory performance.

Is NMP an essential excipient in Eligard-type formulations?

NMP is central to the disclosed PLGA in situ depot approach used by Eligard and related products, but it is not chemically essential to all leuprolide depot technologies. A different solvent or delivery mechanism could support a non-NMP product.

What excipient creates the greatest patent opportunity?

The strongest opportunity is usually a defined combination of polymer grade, solvent system, leuprolide loading, release profile, and delivery device. A claim to a conventional excipient alone is generally easier to challenge than a performance-linked combination claim.

Can a generic company use a different PLGA grade?

Potentially. A different PLGA ratio, molecular weight, end group, or concentration may support a design-around, but the applicant must still demonstrate appropriate pharmaceutical equivalence, bioequivalence, release behavior, and product quality.

Which leuprolide product has the greatest formulation differentiation?

Six-month products such as Fensolvi and Eligard 45 mg have greater formulation and device differentiation than immediate-release leuprolide injection. Their value comes from sustained release, reduced administration frequency, and specialized delivery systems.

References

1. U.S. Food and Drug Administration. (2024). Eligard (leuprolide acetate) for injectable suspension: Prescribing information.
2. U.S. Food and Drug Administration. (2024). Fensolvi (leuprolide acetate) for injectable suspension: Prescribing information.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
4. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. § 355.
5. U.S. Food and Drug Administration. (2024). Lupron Depot (leuprolide acetate) for depot suspension: Prescribing information.
6. U.S. Food and Drug Administration. (2023). Camcevi (leuprolide mesylate) for injectable suspension: Prescribing information.
7. Makadia, H. K., & Siegel, S. J. (2011). Poly lactic-co-glycolic acid as biodegradable controlled drug delivery carrier. Polymers, 3(3), 1377-1397. https://doi.org/10.3390/polym3031377