List of Excipients in Branded Drug NUTROPIN AQ NUSPIN 5

Nutropin AQ NuSpin 5 Excipient Strategy and Commercial Opportunities

Last updated: August 4, 2026

Nutropin AQ NuSpin 5 is a liquid somatropin product supplied in a single-patient-use, prefilled delivery system. Its formulation uses histidine, poloxamer 188, phenol and water for injection. The commercial opportunity is unlikely to come from copying the historical formulation alone. Greater value lies in developing a differentiated somatropin presentation with improved stability, device performance, preservative tolerance, storage conditions, or pediatric usability.

The product is a recombinant human growth hormone biologic, not a conventional small-molecule drug. Regulatory and intellectual-property strategies therefore center on biosimilarity, analytical comparability, device integration, formulation performance and manufacturing controls.

What is Nutropin AQ NuSpin 5?

Nutropin AQ NuSpin 5 is a liquid formulation of somatropin, also known as recombinant human growth hormone. The NuSpin 5 presentation contains 5 mg of somatropin in a cartridge-based delivery device. It was developed for subcutaneous administration in pediatric and adult growth hormone indications under the Nutropin AQ product franchise. The product was associated with Genentech, a member of the Roche Group.

The formulation is designed for refrigerated storage and repeated dose withdrawal from a multidose cartridge. Its excipients support protein stability, surface protection and microbial control.

Attribute	Nutropin AQ NuSpin 5
Active ingredient	Somatropin
Biological class	Recombinant human growth hormone
Dosage form	Sterile liquid injection
Route	Subcutaneous
Strength	5 mg cartridge presentation
Delivery system	NuSpin prefilled injection device
Buffer	Histidine
Surfactant	Poloxamer 188
Preservative	Phenol
Vehicle	Water for injection
Storage	Refrigerated, consistent with product labeling
Regulatory category	Biologic licensed under a BLA
Reference product status	Historical somatropin reference product; product availability and marketing status should be assessed against current FDA records

The FDA-approved labeling identifies histidine, poloxamer 188, phenol and water for injection as the principal inactive ingredients in the Nutropin AQ formulation.[1]

What excipients are used in Nutropin AQ NuSpin 5?

The formulation uses a small excipient system with distinct functional roles.

Excipient	Primary function	Commercial and technical relevance
Histidine	Buffer and pH control	Supports protein stability while limiting ionic strength
Poloxamer 188	Nonionic surfactant	Reduces interfacial stress, aggregation and adsorption
Phenol	Antimicrobial preservative	Enables multidose use but creates tolerability, compatibility and extractables considerations
Water for injection	Solvent	Provides the aqueous vehicle for the injectable formulation

Why is histidine used?

Histidine provides buffering capacity in the mildly acidic pH range used for the product. Histidine buffers are common in protein formulations because they can provide pH control without the higher ionic load associated with some phosphate-based systems.

For a somatropin product, pH control matters because changes in pH can affect:

• Protein aggregation
• Chemical degradation
• Deamidation
• Oxidation
• Surface adsorption
• Container closure compatibility

A follow-on product does not necessarily need to use histidine. A developer could evaluate phosphate, citrate, acetate or alternative histidine concentrations, but a change in buffer would require comparative data showing acceptable potency, purity, aggregation profile, osmolality and injection performance.

Why is poloxamer 188 used?

Poloxamer 188 protects proteins against agitation and interfacial stress. This is relevant to a cartridge device that is handled repeatedly, transported through the cold chain and used for multiple injections.

Poloxamer 188 can reduce adsorption to:

• Glass and polymer surfaces
• Cartridge components
• Syringe and needle interfaces
• Air-liquid interfaces
• Manufacturing equipment

The excipient also creates control requirements. Poloxamer 188 may contain peroxide impurities that can contribute to protein oxidation. A commercial formulation strategy therefore requires supplier qualification, peroxide control, lot-to-lot monitoring and compatibility testing with the primary container.

Why is phenol used?

Phenol is used as a preservative for multidose delivery. Its inclusion supports repeated access to the cartridge after initial use.

Phenol creates several development and commercial considerations:

• Injection-site tolerability
• Local pain or irritation
• Preservative concentration control
• Container and elastomer compatibility
• Extractables and leachables
• Patient preference for preservative-free products
• Pediatric acceptance and adherence

A preservative-free presentation could be commercially differentiated, but it would generally require a different device and use model. A single-use pen, prefilled syringe or short-use cartridge could reduce the need for phenol. The tradeoff is higher packaging cost, more waste and potentially more frequent device replacement.

What formulation patents protect Nutropin AQ NuSpin 5?

The commercially relevant protection for Nutropin AQ NuSpin 5 historically involved several layers:

1. Somatropin composition and production technology.
2. Stabilized aqueous growth hormone formulations.
3. Multidose cartridge and injection-device configurations.
4. Manufacturing and filling processes.
5. Method-of-use claims for approved growth hormone indications.
6. Trade secrets covering cell culture, purification, formulation processing and device assembly.

The original formulation, delivery-device and product-specific patent positions are likely to have matured or expired because Nutropin AQ was introduced decades ago. A current freedom-to-operate analysis must separately review issued patents, patent-term adjustments, terminal disclaimers, continuations, reissues and active device patents. Historical patent protection should not be treated as a current barrier without a live patent-family review.

Are the Nutropin AQ excipients themselves strongly patentable?

The individual excipients are established pharmaceutical ingredients and generally do not provide meaningful standalone exclusivity. A defensible patent position would more likely depend on a specific combination or performance limitation, such as:

• A defined somatropin concentration and pH range
• A narrow histidine-to-surfactant ratio
• Reduced aggregate formation after repeated pen actuation
• Defined phenol and poloxamer concentrations
• Improved stability under temperature excursions
• A cartridge formulation with a specific closure system
• Reduced oxidation associated with low-peroxide poloxamer 188
• A preservative-free composition with a defined in-use period
• A formulation compatible with a particular injection device

Patent strength improves when the claims are linked to measurable technical results rather than a broad list of conventional excipients.

When does Nutropin AQ NuSpin 5 lose exclusivity?

Nutropin AQ NuSpin 5 is not protected by only one exclusivity date. Its commercial exclusivity depends on biologic exclusivity, patent status, regulatory status and device protection.

Protection layer	Relevance to Nutropin AQ NuSpin 5
BLA exclusivity	Applies to the licensed biologic product and is separate from patents
Product patents	Historical formulation or product claims may have expired
Device patents	May have covered pen mechanics, cartridges or dose delivery
Method-of-use patents	May cover selected indications or dosing approaches
Manufacturing patents	May protect upstream or downstream production processes
Trade secrets	Can remain commercially relevant after patent expiry
Biosimilar pathway	Enables abbreviated approval based on biosimilarity rather than direct generic substitution

The FDA’s biologics framework generally allows biosimilar applications after the reference product’s statutory exclusivity period. That pathway does not automatically provide pharmacy-level interchangeability. Interchangeability requires a separate determination under the applicable FDA standard.[2]

Nutropin AQ NuSpin 5 should therefore be analyzed as a biologic reference product with potential biosimilar competition, not as a conventional branded injectable with an ordinary Abbreviated New Drug Application pathway.

What is the FDA regulatory status of Nutropin AQ NuSpin 5?

Nutropin AQ was licensed as a somatropin biologic. FDA labeling describes its approved use in growth hormone deficiency and related pediatric indications, subject to the product’s approved prescribing information.[1]

The key regulatory questions for a current commercial program are:

• Whether the specific NuSpin 5 presentation remains marketed
• Whether the BLA is active, withdrawn, or associated with discontinued presentations
• Whether FDA considers the product available as a reference product for biosimilar development
• Whether the proposed follow-on product will use a prefilled device
• Whether the applicant seeks biosimilarity, interchangeability or a standalone BLA
• Whether the proposed formulation uses the same or different excipients

The FDA’s Purple Book, product labeling database and biologics approval records are more relevant than the Orange Book for the reference biologic. The Orange Book is primarily used for approved small-molecule drugs and does not provide the full exclusivity framework for biologic reference products.[2,3]

How strong is the patent estate for a Nutropin AQ follow-on product?

The patent estate is likely strongest around the delivery system and manufacturing process, not the basic excipient composition.

Formulation patent strength

A formulation patent can be commercially useful if it demonstrates an unexpected advantage, such as:

• Lower high-molecular-weight species
• Improved potency retention
• Better stability after agitation
• Lower oxidation during refrigerated storage
• A longer in-use period
• Lower preservative exposure
• Reduced injection force
• Improved compatibility with a polymer cartridge

A claim covering only somatropin, histidine, poloxamer 188 and phenol in conventional ranges would face validity and prior-art risks. The same composition could become more defensible if tied to a validated stability profile, specific impurity limits or device-use conditions.

Device patent strength

The NuSpin system integrates formulation and delivery. Device claims may address:

• Dose-setting mechanisms
• Cartridge piercing
• Needle attachment
• Dose accuracy
• Residual volume
• Pen priming
• Tamper resistance
• Human-factors performance

A follow-on company can reduce device risk by using a different platform, licensing a third-party pen or developing a prefilled syringe. Device redesign does not eliminate regulatory work. Combination-product usability, dose accuracy and container-closure testing remain necessary.

Manufacturing patent strength

Somatropin manufacturing can be protected through process patents and trade secrets involving:

• Recombinant host-cell production
• Protein refolding
• Chromatographic purification
• Viral and microbial control
• Removal of host-cell impurities
• Aggregation reduction
• Aseptic filling

A formulation developer can avoid some process claims by sourcing active pharmaceutical ingredient from a qualified manufacturer, but supplier dependence can reduce margin and complicate change control.

What excipient strategies create commercial opportunities?

Preservative-free somatropin

A preservative-free product could target patients who experience local irritation or prefer lower excipient exposure. The most practical formats are single-use prefilled syringes, single-dose cartridges or short-duration multidose systems using alternative antimicrobial controls.

The main commercial constraints are packaging cost, cold-chain volume, waste and the need to demonstrate microbiological integrity throughout the labeled use period.

Low-phenol or alternative-preservative formulation

A lower-phenol product could preserve multidose functionality while addressing tolerability concerns. Alternative preservatives would require careful evaluation because many antimicrobial agents can destabilize proteins or create local irritation. The product would need preservative-effectiveness data and full container-closure compatibility testing.

Improved poloxamer strategy

A differentiated product could use a low-peroxide grade of poloxamer 188 or another surfactant selected for lower oxidation risk. The opportunity is strongest when the developer can demonstrate:

• Lower oxidized somatropin
• Better potency retention
• Fewer visible and subvisible particles
• Improved stability after repeated device handling
• More consistent performance across supplier lots

This strategy also creates a procurement opportunity. A sponsor could qualify multiple poloxamer suppliers or establish a controlled excipient specification that includes peroxide, moisture, molecular-weight distribution and bioburden limits.

Room-temperature or excursion-tolerant presentation

A somatropin product that tolerates short temperature excursions could reduce pharmacy and patient handling problems. A fully room-temperature product would require substantial stability evidence and may be difficult to achieve without changing the formulation, container or lyophilized state.

A more realistic opportunity is a formulation with a defined excursion window, such as improved stability during transport or temporary loss of refrigeration. This can produce commercial value without requiring unrestricted room-temperature storage.

Higher-concentration formulation

A higher-concentration product could reduce injection volume and improve pediatric usability. The development risks include increased viscosity, higher injection force, greater aggregation potential and altered device performance.

The commercial case depends on whether the product can deliver a meaningful reduction in dose volume without compromising dose accuracy or patient handling.

Lyophilized formulation

A lyophilized somatropin presentation could improve long-term stability and reduce dependence on refrigerated storage. Its disadvantages include reconstitution steps, added packaging, more complicated administration and greater risk of user error.

Lyophilization is more attractive for markets with weak cold-chain infrastructure than for mature markets where liquid pen products dominate.

Which companies compete with Nutropin AQ NuSpin 5?

Somatropin competition includes branded products, biosimilar products and newer long-acting growth hormone products.

Product or company	Active ingredient or approach	Competitive relevance
Genotropin, Pfizer	Somatropin	Established daily growth hormone product
Omnitrope, Sandoz	Somatropin biosimilar to Genotropin	Demonstrates U.S. biosimilar pathway for somatropin
Humatrope, Eli Lilly	Somatropin	Established branded competitor
Norditropin, Novo Nordisk	Somatropin	Pen-based growth hormone competitor
Saizen, Merck KGaA	Somatropin	International growth hormone competitor
Zomacton, Ferring	Somatropin	Alternative presentation and administration options
Skytrofa, Ascendis Pharma	Lonapegsomatropin	Long-acting growth hormone alternative
Ngenla, Pfizer	Somatrogon	Long-acting growth hormone alternative

The competitive threat is not limited to a direct somatropin biosimilar. Long-acting growth hormone products can compete on injection frequency, adherence and patient convenience. A follow-on Nutropin-type product therefore needs a clear positioning advantage, such as lower price, broader access, simpler administration or improved tolerability.

What generic entry risks exist for Nutropin AQ NuSpin 5?

A conventional generic launch is unlikely to be the primary pathway because somatropin is a biologic. The principal entry scenarios are:

1. A biosimilar somatropin with a separate delivery device.
2. A biosimilar somatropin using a cartridge pen.
3. A product with a distinct formulation and standalone BLA.
4. A long-acting growth hormone that displaces daily injections.
5. A regional competitor using a different presentation or manufacturing source.

A biosimilar applicant must establish high similarity to the reference product through structural, functional, purity, potency and clinical evidence. Excipients can differ, but the applicant must show that the differences do not produce clinically meaningful changes in safety, purity or potency.

A different excipient system can be commercially useful because it may avoid formulation claims or improve product performance. It can also create regulatory complexity if the changed excipients affect immunogenicity, tolerability or pharmacokinetics.

What litigation and settlement issues affect Nutropin AQ NuSpin 5?

The main litigation risks are likely to arise from:

• Biosimilar patent litigation under the Biologics Price Competition and Innovation Act
• Device patent disputes
• Formulation patents covering stability or preservative systems
• Manufacturing-process patents
• Trademark and trade-dress claims involving pen presentation
• Contract disputes involving active-ingredient or device suppliers

A biosimilar applicant should conduct a live patent search across the reference-product sponsor, device suppliers, excipient suppliers and formulation licensors. A historical patent-expiration review alone is insufficient because continuation applications and device patents may remain relevant after core composition patents expire.

Settlement agreements could establish delayed entry, manufacturing restrictions or licensing rights. Such agreements should be reviewed for launch-date provisions, geographic limits, authorized biosimilar terms and any restrictions on device substitution.

What licensing opportunities exist for the excipient and device strategy?

Commercial licensing targets include:

• Low-peroxide poloxamer 188 grades
• Protein-stabilizing excipient combinations
• Preservative-free multidose systems
• Prefilled pen platforms
• Cartridge and elastomer technologies
• Long-acting growth hormone delivery systems
• Recombinant somatropin manufacturing processes
• Cold-chain and temperature-excursion technologies

A formulation company can license a pen platform and retain ownership of the excipient composition. A biologics manufacturer can take the opposite approach by controlling the active ingredient and outsourcing the device. The best structure depends on whether the product’s differentiation is formulation-driven or device-driven.

Exclusivity provisions should address field of use, territory, product strength, dosage form, biosimilar status, supply continuity and rights to improvements. Supplier agreements should also control changes to poloxamer grade, phenol quality, cartridge materials and sterilization conditions.

How should a commercial developer prioritize the opportunities?

Priority	Opportunity	Development rationale
1	Device-compatible biosimilar or follow-on somatropin	Directly addresses established use patterns
2	Preservative-reduced or preservative-free product	Creates a tolerability and pediatric-positioning benefit
3	Higher-concentration formulation	Reduces injection volume but increases viscosity and device risk
4	Excursion-tolerant liquid formulation	Improves distribution and patient handling
5	Lyophilized product	Targets cold-chain-limited markets
6	Long-acting formulation	Higher differentiation but substantially greater development cost

The most practical near-term program is a refrigerated liquid somatropin product using a differentiated pen or prefilled syringe. The formulation can remain close to the historical excipient system while introducing a defensible improvement, such as lower peroxide exposure, reduced phenol concentration or better device stability.

Key Takeaways

• Nutropin AQ NuSpin 5 uses histidine, poloxamer 188, phenol and water for injection.
• The excipient system supports pH control, protein stabilization and multidose preservation.
• The strongest commercial opportunities are preservative reduction, device redesign, higher concentration and improved temperature-excursion stability.
• Somatropin follow-on products generally require a biosimilar or biologic regulatory strategy rather than a conventional generic pathway.
• Individual excipients are weak patent assets because they are established pharmaceutical ingredients.
• A stronger patent position would combine specific excipient ranges with measurable stability, device or usability benefits.
• Device patents, manufacturing know-how and supplier controls may create greater practical barriers than the historical formulation itself.
• Long-acting growth hormone products are an important competitive threat to daily somatropin products.
• A follow-on product should compete on price, injection experience, preservative exposure, storage flexibility or dosing convenience.

FAQs

Can Nutropin AQ NuSpin 5 be reformulated without phenol?

Yes, but a preservative-free formulation would generally require a revised container-closure and use model. Single-use or short-use presentations are more practical than a conventional multidose cartridge.

Is poloxamer 188 essential for somatropin stability?

No. Other surfactants may be evaluated, but poloxamer 188 is established for reducing interfacial stress. Any replacement must be assessed for oxidation, aggregation, immunogenicity, container compatibility and injection performance.

Can a biosimilar somatropin use different excipients from Nutropin AQ?

Yes. A biosimilar may use a different excipient system if the sponsor demonstrates that the difference does not create clinically meaningful changes in safety, purity or potency.

Would a higher-concentration Nutropin-type product have stronger patent potential?

Potentially. Higher concentration alone is unlikely to be sufficient, but a patent may be stronger if the formulation demonstrates unexpected stability, acceptable viscosity, reduced injection force or improved device performance.

Does an Orange Book listing determine Nutropin AQ NuSpin 5 patent risk?

No. The Orange Book is not the primary source for biologic reference-product exclusivity. Biosimilar applicants should review the Purple Book, FDA biologics records, patent-family data, device patents and litigation databases.

References

1. Genentech, Inc. (n.d.). Nutropin AQ [somatropin (rDNA origin) injection] prescribing information. U.S. Food and Drug Administration/DailyMed. https://dailymed.nlm.nih.gov/

2. U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. https://purplebooksearch.fda.gov/

3. U.S. Food and Drug Administration. (2024). Biosimilar and interchangeable biosimilar products. https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/biosimilars

4. International Council for Harmonisation. (1995). ICH Q5C: Quality of biotechnological products: Stability testing of biotechnological/biological products. https://www.ich.org/

5. International Council for Harmonisation. (1999). ICH Q6B: Specifications: Test procedures and acceptance criteria for biotechnological/biological products. https://www.ich.org/

6. U.S. Pharmacopeia. (2024). United States Pharmacopeia and National Formulary. U.S. Pharmacopeial Convention.