List of Excipients in Branded Drug LANTUS

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
A-S Medication Solutions	LANTUS	insulin glargine	50090-0876	GLYCERIN
A-S Medication Solutions	LANTUS	insulin glargine	50090-0876	HYDROCHLORIC ACID
A-S Medication Solutions	LANTUS	insulin glargine	50090-0876	METACRESOL

Lantus Excipient Strategy and Commercial Opportunities

Last updated: August 24, 2026

Lantus is insulin glargine U-100, a recombinant human insulin analog formulated as an acidic, zinc-stabilized, preserved aqueous solution. Its excipient system is simple but technically important: glycerol controls tonicity, m-cresol provides antimicrobial preservation, zinc supports insulin association and structural stability, and the formulation is maintained at approximately pH 4.0.[1] The main commercial opportunity is not a direct copy of the excipient list. It is the development of differentiated insulin-glargine products with improved tolerability, device performance, storage flexibility, concentration, or manufacturing economics.

The principal competitive threat to Lantus comes from follow-on and biosimilar insulin glargine products, including Basaglar, Semglee, and Rezvoglar. Excipient differentiation can support product positioning, but it does not by itself create substantial market protection where the active ingredient, route, concentration, and clinical use are already established.

What excipients are used in Lantus?

Lantus U-100 contains insulin glargine, glycerol, m-cresol, zinc, and water for injection. Hydrochloric acid and sodium hydroxide adjust the formulation to approximately pH 4.0.[1]

Component	Function in Lantus	Commercial or technical significance
Insulin glargine	Active pharmaceutical ingredient	Recombinant protein requiring control of aggregation, oxidation, deamidation, and adsorption
Glycerol, 20 mg/mL	Tonicity modifier and stabilizing excipient	Supports injection comfort and solution properties
m-Cresol, 2.7 mg/mL	Antimicrobial preservative	Enables multidose vial and pen presentations
Zinc, approximately 30 mcg/mL	Promotes insulin association and structural stability	Influences hexamer formation, release behavior, and physical stability
Hydrochloric acid and sodium hydroxide	pH adjustment	Maintains the acidic formulation environment
Water for injection	Vehicle	Required for parenteral administration

Lantus is acidic in the vial or pen. After subcutaneous injection, the formulation undergoes a pH shift toward physiological conditions, producing microprecipitates from which insulin glargine is slowly released.[2] This precipitation mechanism is central to the product’s pharmacology and limits the usefulness of excipient substitutions that materially alter solubility or aggregation behavior.

How does the Lantus excipient system work?

The formulation has four interdependent design variables: pH, zinc concentration, preservative concentration, and osmolarity.

pH and precipitation control

Insulin glargine is soluble under the acidic conditions used in Lantus. It becomes less soluble after injection as the formulation is neutralized by tissue fluids. The resulting precipitate acts as a subcutaneous depot.[2]

A competing formulation that changes pH, buffer capacity, ionic strength, or zinc content may alter:

• Depot formation
• Dissolution rate
• Pharmacokinetic variability
• Injection-site tolerability
• Immunogenicity
• Shelf-life stability

This creates a technical barrier for generic or biosimilar developers. The formulation must demonstrate comparable product quality and clinical performance, not simply reproduce the active ingredient concentration.

Zinc as a structural excipient

Zinc is not an incidental trace component. It interacts with insulin molecules and affects association into higher-order structures. A change in zinc level can influence the balance between monomeric, dimeric, and hexameric species, as well as the behavior of the injected depot.

Potential development work includes:

• Zinc concentration screening
• Zinc salt selection
• Control of free versus protein-bound zinc
• Monitoring of subvisible particles
• Assessment of zinc-driven aggregation
• Container compatibility studies

A zinc strategy could support intellectual property around a specific concentration range, but the commercial value depends on whether the change produces a clinically meaningful advantage.

m-Cresol and preservative strategy

m-Cresol is used to control microbial growth in multidose insulin products. Preservative exposure is a potential differentiation point because some patients experience injection-site discomfort or intolerance associated with preservatives, although tolerability is multifactorial.

Possible alternatives include phenol, benzyl alcohol, metacresol at a modified concentration, or preservative-free single-use systems. Each alternative creates tradeoffs involving:

• Antimicrobial effectiveness
• Protein stability
• Container closure compatibility
• Extractables and leachables
• Injection-site tolerability
• Device shelf life
• Regulatory comparability

A preservative-free Lantus-like product is most commercially credible in a prefilled, single-use, unit-dose format. Removing m-cresol from a multidose pen or vial would require a separate microbial-control strategy.

Glycerol and tonicity

Glycerol provides tonicity and can influence protein hydration and solution viscosity. Its concentration affects injection force, dose delivery, and patient comfort.

Commercially relevant formulation work could examine:

• Glycerol concentration ranges
• Alternative tonicity agents
• Lower-viscosity formulations
• Compatibility with autoinjectors
• Reduced injection force for elderly patients
• Stability during temperature excursions

Excipient substitution is most valuable when paired with a device or administration benefit. A formulation change that has no measurable impact on adherence, usability, or stability is unlikely to support premium pricing.

What patents protect Lantus excipients and formulation?

Lantus’s original composition and insulin-glargine patent estate has largely matured, allowing follow-on insulin glargine products to enter the U.S. market. The original insulin-glargine patent was U.S. Patent No. 5,656,722, which expired in 2015 after the applicable patent term.[3]

The commercial protection for Lantus has therefore shifted from basic composition claims toward:

• Product-specific formulation claims
• Device and cartridge claims
• Manufacturing processes
• Stability improvements
• Injection systems
• Concentrated insulin-glargine formulations
• Method-of-use claims
• Regulatory exclusivity and commercial contracting

Excipient claims are strongest when they define a measurable technical result, such as improved stability, reduced aggregation, controlled precipitation, or extended storage under defined conditions. A claim directed only to a conventional preservative or tonicity agent is more vulnerable to validity and obviousness challenges.

What formulation patents are commercially valuable?

The most valuable formulation claims would typically cover combinations of:

1. Insulin glargine at a defined concentration.
2. A specified zinc-to-protein ratio.
3. A narrow pH range.
4. A selected preservative or preservative-free system.
5. A defined level of high-molecular-weight protein species.
6. Improved stability after agitation, freezing excursions, or elevated temperature.
7. Compatibility with a particular pen or cartridge.

Manufacturing claims can be more durable than simple composition claims when they address control of insulin folding, refolding, purification, zinc incorporation, or removal of process-related impurities.

When does Lantus lose exclusivity?

Lantus lost core U.S. patent exclusivity after the expiration of the original insulin-glargine patent in 2015. FDA approved Basaglar, insulin glargine injection, under the 505(b)(2) pathway in 2015, with Eli Lilly and Boehringer Ingelheim commercializing the product.[4]

FDA later approved Semglee, insulin glargine-yfgn, as a biosimilar to Lantus in 2020 and designated it interchangeable in 2021.[5] Rezvoglar, insulin glargine-aglr, was approved in 2022 and became commercially available as another interchangeable biosimilar product.[6]

Product	Active ingredient	FDA pathway or status	Key U.S. milestone
Lantus	Insulin glargine	Reference product	Original approval in 2000
Basaglar	Insulin glargine	505(b)(2) follow-on	Approved 2015
Semglee	Insulin glargine-yfgn	Biosimilar; interchangeable	Biosimilar approval in 2020; interchangeability in 2021
Rezvoglar	Insulin glargine-aglr	Biosimilar; interchangeable	Approved in 2022

FDA’s transition of insulin products from the drug framework to the biologics framework increased the importance of the biosimilar pathway for follow-on insulin products.[7] The active ingredient is now regulated as a biologic under the Public Health Service Act, while approved insulin products retain their established market positions.

What is the Orange Book status of Lantus?

Lantus was originally approved as NDA 021081. FDA’s Orange Book historically listed patent information associated with the approved drug product, but the core insulin-glargine patent protection has expired.[8]

For market-entry analysis, an applicant must separate three issues:

• Whether a listed patent remains enforceable.
• Whether the patent claims the reference formulation, device, or method of use.
• Whether the proposed product can be approved without infringing the relevant claims.

An excipient change can reduce infringement exposure, but it can also create a new regulatory comparability burden. A product that avoids a formulation claim but loses equivalence in release, stability, or immunogenicity may have limited commercial value.

Which companies are challenging Lantus?

The principal U.S. challengers are Eli Lilly and Boehringer Ingelheim through Basaglar, Viatris and Biocon Biologics through Semglee, and Eli Lilly through Rezvoglar.[4-6]

The competitive field is based on more than active ingredient similarity. Key differentiators include:

• Wholesale acquisition cost
• Formulary placement
• Interchangeability
• Pen design
• Dose-counter reliability
• Supply continuity
• Patient support
• Contracting with pharmacy benefit managers
• Hospital and government purchasing agreements

Interchangeability has particular commercial value because pharmacists may substitute an interchangeable biosimilar under state law without prescriber intervention, subject to state-specific requirements.[5]

What generic entry risks exist for Lantus?

Lantus faces three principal entry risks.

Price erosion

Insulin glargine products can compete directly on net price because the market has several approved alternatives. Rebates and formulary contracts can be more important than list price. A new entrant with a lower-cost formulation may gain access through public programs or employer plans even without a major clinical differentiation.

Formulary displacement

Payers can prefer one glargine product over another when products are clinically similar. A lower-cost biosimilar can pressure Lantus pricing and increase rebate demands from incumbent manufacturers.

Device-driven switching

Pen compatibility and training can create persistence for Lantus, but a challenger with an easier-to-use pen, lower injection force, or better dose feedback can overcome some switching barriers.

How strong is the Lantus patent estate?

The original composition estate is weak from a market-exclusivity perspective because the principal patent term has expired. The remaining defensibility is more likely to come from product execution, device patents, manufacturing know-how, trademarks, regulatory history, and payer contracts.

Estate category	Relative strength	Commercial implication
Original insulin-glargine composition	Low after expiration	Does not block approved follow-on products
Basic excipient combination	Low to moderate	Vulnerable unless tied to a narrow technical result
Device and delivery system	Moderate	Can delay direct substitution or increase switching costs
Manufacturing process	Moderate to strong if difficult to reproduce	May protect quality and yield rather than market exclusivity
Concentrated or modified formulation	Potentially strong	Depends on clinical differentiation and claim scope
Trademark and brand recognition	Commercially strong	Supports retention but does not prevent biosimilar approval
Payer contracts	Variable	Can preserve volume despite patent expiry

What excipient opportunities exist for new insulin-glargine products?

Preservative-free single-use delivery

A preservative-free insulin-glargine product could target patients with suspected preservative intolerance and reduce excipient exposure. The most practical presentation is a single-use cartridge, syringe, or disposable pen.

The opportunity is constrained by higher packaging cost, greater waste, and the need to demonstrate sterility throughout the shelf life.

Lower-injection-force formulations

A formulation with lower viscosity or improved lubricity could support a pen requiring less thumb force. This is relevant to patients with arthritis, neuropathy, or reduced hand strength.

The commercial case is strongest when formulation and device are developed together. A lower-force formulation without a differentiated delivery system may be difficult to monetize.

More robust temperature stability

Insulin supply chains in emerging markets face temperature excursions. A formulation that maintains potency and limits aggregation during short-term heat exposure could support institutional procurement and geographic expansion.

Stability claims should be tied to defined storage conditions and analytical endpoints. “Room-temperature stable” is not sufficient unless the label and regulatory data support the exact storage statement.

Higher concentration

U-300 insulin glargine is already commercialized by Sanofi as Toujeo, so concentration alone is not an open white space for a new Lantus product.[9] A new U-300 strategy would require a clear benefit in injection volume, dose burden, duration, titration, or device performance.

Alternative preservatives

A new preservative system could reduce local irritation or improve protein stability, but it creates a high burden of antimicrobial validation, extractables testing, and clinical comparability. The best commercial target is a measurable tolerability or shelf-life improvement rather than a simple substitution.

Excipient systems for biosimilar robustness

Biosimilar developers can use excipient optimization to improve:

• Oxidative stability
• Agitation resistance
• Freeze-thaw resistance
• Recovery from cartridge surfaces
• Compatibility with silicone oil
• Low-dose delivery accuracy
• Reduced visible and subvisible particles

These improvements may generate manufacturing and quality advantages even if they do not justify a separate premium product.

How does Lantus compare with competing insulin products?

Product	Concentration	Key formulation or product distinction	Strategic implication
Lantus	U-100	Acidic insulin-glargine solution with glycerol, m-cresol, and zinc	Reference product with strong brand recognition
Basaglar	U-100	Follow-on insulin glargine	Price and contracting competitor
Semglee	U-100	Interchangeable insulin glargine-yfgn	Pharmacy substitution advantage
Rezvoglar	U-100	Interchangeable insulin glargine-aglr	Additional biosimilar price pressure
Toujeo	U-300	Concentrated insulin glargine	Lower injection volume and differentiated dosing profile
Tresiba	U-100/U-200	Insulin degludec	Long-acting competitor with a different molecular and formulation profile

Toujeo competes through concentration and dosing characteristics rather than direct U-100 substitution.[9] Tresiba competes at the basal-insulin level but does not use insulin glargine as its active ingredient. A Lantus excipient strategy must therefore define whether it targets direct glargine substitution or broader basal-insulin competition.

What regulatory pathway applies to a new Lantus-like product?

A product with insulin glargine as the active ingredient may be developed as a biosimilar under section 351(k), subject to FDA requirements for analytical similarity, pharmacokinetic and pharmacodynamic comparability, immunogenicity, and manufacturing controls.[7]

A materially altered formulation may require additional bridging work. The regulatory burden increases with changes to:

• Concentration
• Route or device
• Preservative system
• pH
• Zinc level
• Release behavior
• Dosing schedule
• Container closure
• Storage conditions

A conventional generic-style pathway is less relevant for new insulin-glargine development after the insulin transition to the biologics framework. FDA approval strategy must align the formulation, device, and interchangeability objective from the start.

What manufacturing and intellectual-property barriers matter?

The major barriers are process control and analytical comparability. Insulin glargine production requires control of recombinant expression, folding, purification, chemical conversion, impurity clearance, and final formulation.

Critical quality attributes include:

• Primary structure
• Correct disulfide pairing
• Glycation and oxidation
• Deamidation
• Aggregates and particles
• Potency
• Zinc content
• Preservative content
• pH and osmolality
• Container interaction
• Delivered dose accuracy

Manufacturing know-how can create a practical barrier even when composition patents have expired. A supplier with a lower-cost process, higher yield, or stronger cold-chain performance can improve margins without changing the clinical profile.

Geographic opportunities are strongest where insulin access is constrained by price, cold-chain reliability, or limited competition. Local fill-finish, regional device assembly, and contract manufacturing can reduce logistics costs. Those models still require compliance with FDA, EMA, and local good manufacturing practice requirements.

What revenue exposure does Lantus face?

Sanofi reported Lantus sales of approximately 2.5 billion euros in 2023, with biosimilar and follow-on competition contributing to pressure on the franchise.[10] The revenue exposure is concentrated in mature markets where insulin glargine has multiple approved alternatives and payers can use formulary tools.

The most defensible revenue segments are:

• Patients stabilized on existing Lantus pens
• Markets with strong brand or physician loyalty
• Contracts where supply reliability is valued
• Patients requiring established device support
• Regions where competing biosimilar availability remains limited

The highest-risk segments are price-sensitive formularies, government tenders, and channels where interchangeable biosimilars receive automatic or near-automatic substitution.

Key Takeaways

• Lantus uses a compact excipient system based on glycerol, m-cresol, zinc, water, and pH adjustment.
• The acidic formulation and post-injection precipitation mechanism are central to insulin-glargine performance.
• Core Lantus patent exclusivity has expired, and the U.S. market includes Basaglar, Semglee, and Rezvoglar.
• The strongest new opportunities are preservative-free single-use delivery, improved temperature stability, lower-force administration, and manufacturing-cost reduction.
• Excipient changes must be evaluated with the device, container, stability program, and regulatory pathway as one product system.
• Formulation patents are more defensible when linked to measurable technical effects rather than conventional excipient selections.
• Interchangeable biosimilars create the greatest substitution and pricing risk in the U.S. market.
• Lantus commercial protection now depends more on brand, device, supply, contracting, and manufacturing capabilities than on basic composition patents.

FAQs

Can m-cresol be removed from a Lantus biosimilar?

Yes, but removal would materially change the preservative and packaging strategy. A preservative-free product would likely require a single-use presentation and supporting sterility, stability, and container-closure data.

Is zinc essential to insulin glargine formulation?

Zinc is not universally required for every insulin-glargine formulation, but it is important to the Lantus formulation and can affect association, stability, aggregation, and depot behavior. Any change requires analytical and clinical comparability assessment.

Does a different excipient combination avoid Lantus patent infringement?

Not necessarily. Infringement depends on the claims of each enforceable patent. A different excipient system may avoid a composition claim while creating separate regulatory risks or falling within a broader formulation or method claim.

Can a new insulin-glargine product receive interchangeable status?

Potentially. Interchangeability requires satisfaction of FDA’s biosimilar and switching-related requirements. Excipient changes that affect pharmacokinetics, immunogenicity, or product performance can complicate that designation.

Is a preservative-free insulin-glargine product commercially attractive?

It can be attractive for targeted populations, but the business case depends on incremental clinical or usability value. Higher packaging and manufacturing costs can offset the benefit unless the product supports premium reimbursement or reduces adherence barriers.

References

1. U.S. Food and Drug Administration. (2024). Lantus insulin glargine injection prescribing information. Sanofi-Aventis U.S. LLC.

2. Owens, D. R. (2002). Glargine and its use in the treatment of type 1 and type 2 diabetes mellitus. Expert Opinion on Pharmacotherapy, 3(4), 529-540.

3. U.S. Patent No. 5,656,722. (1997). Insulin derivatives.

4. U.S. Food and Drug Administration. (2015). Basaglar approval package. Center for Drug Evaluation and Research.

5. U.S. Food and Drug Administration. (2021). FDA approves first interchangeable biosimilar insulin product for treatment of diabetes. FDA.

6. U.S. Food and Drug Administration. (2022). Rezvoglar approval package. Center for Drug Evaluation and Research.

7. U.S. Food and Drug Administration. (2019). Clinical immunogenicity considerations for biosimilar and interchangeable insulin products. FDA.

8. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.

9. U.S. Food and Drug Administration. (2024). Toujeo insulin glargine injection prescribing information. Sanofi-Aventis U.S. LLC.

10. Sanofi. (2024). 2023 universal registration document and annual financial report. Sanofi.