List of Excipients in Branded Drug NOVOLOG

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	GLYCERIN
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	HYDROCHLORIC ACID
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	METACRESOL
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	PHENOL
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	SODIUM CHLORIDE
TYA Pharmaceuticals	NOVOLOG	insulin aspart	64725-0750	SODIUM HYDROXIDE

NovoLog Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

NovoLog is insulin aspart, a rapid-acting recombinant human insulin analog marketed by Novo Nordisk. Its commercial formulation uses conventional parenteral excipients: glycerin for tonicity, phenol and metacresol for antimicrobial preservation, zinc for insulin association, phosphate for buffering, and water for injection. The highest-value opportunities are not simple excipient substitution. They are improved stability, pump compatibility, preservative reduction, concentrated presentations, cold-chain resilience, and differentiated delivery systems.

What excipients are used in NovoLog?

NovoLog injection contains insulin aspart at 100 units/mL with a pH of approximately 7.2 to 7.6. The U.S. prescribing information identifies the following inactive ingredients.[1]

Component	Approximate concentration	Functional role
Glycerin	16 mg/mL	Tonicity and formulation support
Phenol	1.5 mg/mL	Antimicrobial preservative
Metacresol	1.72 mg/mL	Antimicrobial preservative and protein-stability support
Zinc	19.6 mcg/mL	Insulin hexamer formation and physical stability
Disodium phosphate	1.25 mg/mL	Buffering and pH control
Water for injection	q.s.	Vehicle

NovoLog is supplied in vials, FlexPen prefilled pens, and PenFill cartridges. The formulation is also used in pump therapy, subject to device-specific instructions and stability limits.[1]

The excipient system is commercially important because insulin is sensitive to aggregation, fibrillation, adsorption to surfaces, oxidation, agitation, temperature, and repeated exposure to air. Excipients must preserve potency without impairing subcutaneous absorption or device performance.

How does the NovoLog formulation compare with Fiasp and other rapid-acting insulins?

NovoLog uses a conventional rapid-acting insulin formulation. Fiasp, also insulin aspart, adds niacinamide and L-arginine to accelerate initial absorption and improve formulation stability.[2]

Product	Active ingredient	Key formulation distinction	Commercial positioning
NovoLog/NovoRapid	Insulin aspart	Conventional phenol, metacresol, glycerin, zinc and phosphate system	Established rapid-acting insulin
Fiasp	Insulin aspart	Niacinamide supports faster absorption; L-arginine supports stability	Faster onset and mealtime flexibility
Humalog	Insulin lispro	Different insulin analog and excipient system	Competing rapid-acting insulin
Lyumjev	Insulin lispro	Citrate and treprostinil support faster absorption	Ultra-rapid insulin
Apidra	Insulin glulisine	Different insulin analog and formulation	Rapid-acting alternative

Fiasp demonstrates the most direct commercial route for excipient innovation in the insulin-aspart class. A developer that can improve onset, reduce injection discomfort, extend pump residence time, or improve room-temperature stability could create a differentiated product without changing the insulin sequence.

What formulation opportunities exist around NovoLog?

Faster absorption

The clearest opportunity is an ultra-rapid insulin aspart formulation. Niacinamide is the best-known precedent because it increases local blood flow and accelerates insulin absorption. Other absorption-modifying approaches may include:

• Local vasodilatory excipients
• Permeation enhancers
• Microenvironment pH adjustment
• Controlled particle or complex formation
• Low-viscosity delivery systems
• Microneedle or intradermal delivery

The development risk is high. Absorption enhancers can increase injection-site reactions, systemic exposure variability, or dose-to-dose inconsistency. FDA review would likely focus on pharmacokinetic comparability, hypoglycemia timing, local tolerability, and device compatibility.

Preservative reduction

Phenol and metacresol are effective but can cause local tolerability concerns and may interact with insulin formulations, elastomers, and delivery devices. Opportunities include:

• Lower-preservative multidose formulations
• Alternative antimicrobial systems
• Preservative-free single-use cartridges
• Device-based sterile barriers
• Improved container closure systems

A preservative-free presentation would have the strongest commercial value in single-use pens, patch pumps, and hospital settings. The tradeoff is increased manufacturing and packaging cost, plus more demanding sterility controls.

Improved temperature stability

Insulin products are vulnerable to heat exposure during transport and use. Excipient strategies could target:

• Reduced aggregation after thermal excursions
• Lower fibrillation during agitation
• Improved stability in pen reservoirs and pump cartridges
• Extended in-use storage
• Reduced potency loss after repeated temperature cycling

Candidate approaches include optimized surfactants, amino acids, polyols, chelators, buffering systems, and protein-stabilizing combinations. Any change must be evaluated for extractables and leachables, subvisible particles, oxidation, and delivered-dose accuracy.

Pump compatibility

Pump use creates a distinct formulation problem. Insulin remains in a reservoir or infusion set for days and may contact plastics, adhesives, tubing, and metal components. The key failure modes are aggregation, occlusion, adsorption, precipitation, and preservative migration.

A commercial formulation designed specifically for pumps could compete through:

• Longer allowable reservoir residence
• Lower infusion-set occlusion rates
• Reduced adsorption to tubing
• Better stability under body-temperature conditions
• Compatibility with automated insulin-delivery systems
• Lower interaction with silicone oil and elastomer components

Pump-specific claims can provide stronger differentiation than a general injectable formulation claim because they link the excipient system to a defined use environment.

What patents protect NovoLog and its excipient system?

NovoLog's core composition is mature. The insulin aspart active-ingredient patent estate is substantially older than the product's current commercial lifecycle, while later protection has focused on formulations, delivery devices, manufacturing processes, and methods of use.

Protection category	Relevance to NovoLog	Commercial implication
Insulin aspart composition	Protects the analog sequence and related products	Limited value if expired or near expiry
Formulation composition	Covers excipient ratios, pH, concentration, and stability	Can delay close substitutes if claims remain enforceable
Pen and cartridge systems	Covers device architecture and dose delivery	Creates design-around requirements
Pump-use methods	Covers stability or administration in infusion systems	Relevant to pump competitors
Manufacturing processes	Covers expression, purification, crystallization, or formulation steps	Can raise CMC barriers
Combination or dosing methods	Covers use with diabetes therapies or patient groups	Narrower commercial scope

The U.S. product is associated with NDA 020986. FDA's Orange Book should be used to confirm listed patents, expiration dates, pediatric extensions, and whether any listed patent has been delisted or withdrawn.[3] A precise live-patent opinion requires reviewing each listed patent, terminal disclaimer, patent-term adjustment, continuation, reissue, and litigation outcome.

The main strategic point is that an excipient developer should not assume that a new excipient combination is free of blocking rights. A formulation can avoid the original insulin-aspart composition claims and still implicate later claims directed to concentration, pH, preservatives, pump use, or device cartridges.

When does NovoLog lose exclusivity?

NovoLog's regulatory exclusivity and patent exclusivity are separate issues.

The product was approved in the United States in 2000.[1] Its original small-molecule-style regulatory exclusivity period is no longer the principal barrier to competition. The relevant barriers now involve:

1. Listed patents and any surviving claims.
2. Biologic or insulin regulatory pathway requirements.
3. Manufacturing comparability.
4. Device and cartridge compatibility.
5. State substitution and pharmacy-channel rules.
6. Commercial access to formulary and rebate contracts.

Insulin products approved before the March 23, 2020 transition date were generally handled through the FDA's transition from the Federal Food, Drug, and Cosmetic Act to the Public Health Service Act. FDA treats insulin as a biological product for regulatory purposes, but the applicable reference-product and interchangeability analysis depends on the specific product and approval pathway.[4]

There is no single "NovoLog expiration date" that captures all commercial risk. Core exclusivity, listed patents, device rights, manufacturing know-how, and payer contracts can expire at different times.

What is the Orange Book status of NovoLog?

NovoLog is listed by FDA under NDA 020986. The Orange Book is the relevant source for U.S. listed patent and exclusivity information for the NDA.[3]

The Orange Book does not capture every right that may affect competition. It generally does not provide a complete view of:

• Unlisted formulation know-how
• Trade secrets
• Device patents not listed against the NDA
• Manufacturing process patents
• Foreign rights
• Contractual licensing restrictions
• Patent disputes that do not involve an Orange Book-listed patent

A competitive assessment should therefore combine the Orange Book with USPTO records, FDA approval documents, patent-family analysis, and litigation dockets.

Which companies are challenging NovoLog?

Competition comes from several groups rather than one direct challenger.

Rapid-acting insulin competitors

Eli Lilly competes through Humalog and Lyumjev. Sanofi competes through Apidra. These products use different insulin analogs and formulation strategies, limiting the value of a direct excipient-only substitution.

Follow-on and biosimilar developers

Potential insulin-aspart competitors must establish analytical similarity, biological activity, immunogenicity, pharmacokinetic and pharmacodynamic comparability, and manufacturing consistency. The challenge is greater than copying a conventional small-molecule tablet because insulin is a complex protein with aggregation and structural attributes that affect clinical performance.

Device and pump companies

Medtronic, Tandem Diabetes Care, Insulet, and other automated insulin-delivery companies create a separate channel for formulation innovation. A product optimized for pump stability may obtain commercial traction even without a major change in injection performance.

Contract manufacturers and specialty developers

Contract development and manufacturing organizations can commercialize excipient platforms through licensing, formulation partnerships, or supply agreements. Their most defensible assets are usually formulation know-how, analytical methods, container-closure compatibility data, and scale-up experience.

What Paragraph IV and litigation risks exist?

A conventional generic drug application may not provide the only pathway for insulin aspart competition. Depending on the product and legal pathway, a challenger may pursue an abbreviated application, a biosimilar application, or another FDA route.

For a product referencing NovoLog, the principal U.S. litigation risks include:

• Paragraph IV certification against an Orange Book-listed patent
• Declaratory judgment actions involving patent listing or infringement
• Patent litigation over pen, cartridge, or pump-related claims
• Trade-secret disputes involving manufacturing processes
• Antitrust claims tied to device exclusivity or contracting
• Settlement agreements that delay launch or impose licensing terms

No broad commercial conclusion should be drawn from the absence of a high-profile Paragraph IV case. Insulin competition can be constrained by manufacturing complexity and payer economics even after patents cease to block approval.

What licensing deals could create commercial opportunities?

The strongest licensing targets fall into five categories:

Opportunity	Potential partner	Monetization model
Ultra-rapid absorption excipient	Insulin manufacturer	Upfront payment, milestones, royalties
Pump-stability formulation	Pump or automated-delivery company	Co-development and supply agreement
Room-temperature stability	Insulin manufacturer or global distributor	Regional license and technology-transfer fee
Preservative-reduced formulation	Specialty injectable company	Product-specific license
Container and device compatibility	Pen, cartridge, or pump manufacturer	Component supply or cross-license

A platform company should seek claims that cover the excipient combination, concentration ranges, pH, insulin concentration, use in a delivery device, and stability performance. A single narrow composition claim is less valuable than a coordinated estate covering formulation, method of use, device compatibility, and manufacturing.

How strong is the NovoLog patent estate?

The estate is strongest where it combines technical barriers with commercial switching costs. Core insulin-aspart claims are less likely to provide the principal barrier than later rights involving:

• Prefilled pens and cartridges
• Pump-specific stability
• High-concentration insulin
• Manufacturing yields and purification
• Storage and in-use stability
• Combination with automated dosing algorithms
• Formulation changes that enable faster absorption

The practical strength of an excipient patent depends on more than claim duration. Important variables include whether the claim reads on commercially necessary concentrations, whether competitors can use a different preservative or buffer, whether analytical methods can detect infringement, and whether the formulation produces a measurable clinical benefit.

What generic launch scenarios exist for NovoLog?

Scenario 1: Conventional follow-on insulin

A competitor launches a product with comparable insulin-aspart performance and a different excipient ratio. Price competition is substantial, but switching may be limited by formulary contracts and pen familiarity.

Scenario 2: Authorized or branded lower-price product

A manufacturer uses an existing insulin supply chain to offer a lower-priced presentation. This approach reduces development risk and can reach the market faster than a new excipient platform.

Scenario 3: Ultra-rapid formulation

A competitor uses an absorption-enhancing excipient to claim faster onset or greater mealtime flexibility. The product may command a premium but must demonstrate clinically meaningful differentiation.

Scenario 4: Pump-optimized insulin

The product targets automated insulin delivery and extended reservoir residence. Device partnerships and technical compatibility become more important than retail pharmacy substitution.

Scenario 5: Cold-chain-reduced product

A formulation with improved temperature stability targets emerging markets, disaster response, military logistics, and patients with inconsistent refrigeration. Regulatory evidence must establish potency and safety after defined temperature excursions.

What geographic opportunities exist?

The United States has the highest value for formulation and device innovation but also the most complex patent, reimbursement, and substitution environment. Europe rewards products that improve delivery convenience and health-system economics. Emerging markets offer larger opportunities for room-temperature stability, lower manufacturing cost, and robust multidose presentations.

A global strategy should separate:

• U.S. Orange Book and patent litigation risk
• European patent validation and opposition risk
• Biosimilar and interchangeability rules
• Local device registration
• Import and cold-chain requirements
• Government procurement pricing
• Local manufacturing incentives

A formulation patent should be filed before public disclosure and structured across the United States, Europe, Japan, China, India, Brazil, and other priority markets. Manufacturing-process claims may be particularly valuable in jurisdictions where composition claims are easier to design around.

Key Takeaways

• NovoLog uses a conventional insulin formulation based on glycerin, phenol, metacresol, zinc, phosphate, and water for injection.
• The most attractive commercial opportunities are faster absorption, pump stability, preservative reduction, thermal stability, and differentiated delivery.
• Fiasp demonstrates that excipient innovation can create a distinct insulin-aspart product without changing the active analog.
• NovoLog competition depends on more than Orange Book patents. Device rights, manufacturing know-how, payer contracts, and regulatory pathway selection are material.
• A durable excipient patent estate should cover composition, concentration, pH, device use, stability performance, and manufacturing.
• The strongest launch opportunities target automated insulin delivery, low-resource cold-chain settings, and products with measurable patient or health-system benefits.

FAQs

Can NovoLog excipients be replaced without changing the active ingredient?

Yes. A developer can change preservatives, buffers, stabilizers, tonicity agents, or absorption enhancers, but the resulting product requires full pharmaceutical development and FDA review appropriate to its regulatory pathway.

Does Fiasp have the same excipients as NovoLog?

No. Fiasp contains niacinamide and L-arginine in addition to its insulin-aspart formulation system. These excipients support faster absorption and formulation stability.[2]

Are insulin excipients protected by patents?

They can be. Patent claims may cover an excipient combination, concentration range, pH, insulin concentration, device use, or stability result. Patentability depends on novelty, nonobviousness, written description, enablement, and claim scope.

Is a pump-compatible insulin formulation commercially valuable?

Yes. Pump compatibility can support product differentiation through lower occlusion risk, reduced aggregation, longer reservoir residence, and improved performance in automated insulin-delivery systems.

Can a competitor launch insulin aspart after NovoLog patents expire?

Potentially, but patent expiry does not eliminate regulatory, manufacturing, device, reimbursement, and supply-chain barriers. The launch pathway depends on the product's regulatory classification and FDA requirements.

References

1. U.S. Food and Drug Administration. (2023). NovoLog (insulin aspart injection) prescribing information. Novo Nordisk Inc.

2. U.S. Food and Drug Administration. (2023). Fiasp (insulin aspart injection) prescribing information. Novo Nordisk Inc.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.

4. U.S. Food and Drug Administration. (2020). Transition plan for insulin and other biological products regulated under the Federal Food, Drug, and Cosmetic Act. U.S. Department of Health and Human Services.