List of Excipients in Branded Drug CISATRACURIUM BESYLATE

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Generic Drugs Containing CISATRACURIUM BESYLATE

Company	Ingredient	NDC	Excipient
Hikma Pharmaceuticals USA Inc	cisatracurium besylate	0143-9396	BENZENESULFINIC ACID
Hikma Pharmaceuticals USA Inc	cisatracurium besylate	0143-9396	WATER
Hikma Pharmaceuticals USA Inc	cisatracurium besylate	0143-9397	BENZENESULFINIC ACID
Hikma Pharmaceuticals USA Inc	cisatracurium besylate	0143-9397	BENZYL ALCOHOL
Hikma Pharmaceuticals USA Inc	cisatracurium besylate	0143-9397	WATER
Hospira Inc	cisatracurium besylate	0409-1098	BENZENESULFONIC ACID

What are the Most Frequently-Used Excipients in CISATRACURIUM BESYLATE?

# Of NDCs	Excipient
3	BENZENESULFINIC ACID
31	BENZENESULFONIC ACID
12	BENZYL ALCOHOL
1	NITROGEN
30	WATER

Cisatracurium Besylate Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

Cisatracurium besylate is an established injectable neuromuscular blocking agent with limited formulation complexity and substantial generic competition. The commercial opportunity is not a new active-ingredient franchise. It is a differentiated injectable platform based on supply reliability, ready-to-use presentation, container-closure performance, concentration selection, and hospital workflow.

The core formulation uses cisatracurium besylate in an aqueous solution acidified with benzenesulfonic acid and packaged for parenteral administration. Excipient freedom is narrow because the product must preserve chemical stability, sterility, pH control, low particulate burden, and compatibility with infusion systems. The strongest near-term opportunities are preservative-free ready-to-administer presentations, prefilled syringes, pharmacy-efficient vial sizes, and robust room-temperature handling where supported by stability data.

What is cisatracurium besylate and how is it used?

Cisatracurium besylate is the besylate salt of cisatracurium, an intermediate-duration, nondepolarizing neuromuscular blocking agent. It is administered intravenously to facilitate tracheal intubation, provide skeletal-muscle relaxation during surgery, and support mechanical ventilation in intensive-care settings. FDA-approved labeling identifies use in adults and pediatric patients, with dosing based on clinical circumstances and neuromuscular monitoring.[1]

Cisatracurium is the 1R-cis, 1'R-cis isomer of atracurium. It undergoes Hofmann elimination and ester hydrolysis, which reduces dependence on hepatic and renal clearance relative to several competing neuromuscular blockers.[1,2]

What dosage forms are commercially relevant?

The commercial dosage form is a sterile intravenous solution. Key presentations include:

Product attribute	Commercial relevance
Active ingredient	Cisatracurium besylate
Route	Intravenous
Dosage form	Sterile aqueous injection
Common strength	2 mg/mL
Higher-strength opportunity	10 mg/mL, subject to approved product configuration
Typical packaging	Single-dose glass vial
Preservative strategy	Preservative-free presentation is preferred for intravenous use
Storage	Refrigerated storage is generally required for labeled products
Primary customers	Hospitals, operating rooms, intensive-care units, group purchasing organizations
Regulatory route	Abbreviated New Drug Application for equivalent products; 505(b)(2) may apply to materially different presentations

The product is generally supplied as a single-dose injectable. Product-specific labels should control strength, storage, dilution, compatibility, and discard requirements.[1,3]

What excipients are used in cisatracurium besylate injection?

The reference formulation is intentionally simple. Public labeling identifies water for injection and benzenesulfonic acid as inactive components in the injectable formulation.[1,3]

Excipient or component	Function	Commercial assessment
Water for injection	Vehicle	Standard parenteral vehicle with low regulatory risk
Benzenesulfonic acid	Acidifying agent and pH-control component	Important to maintain product stability and the selected pH range
Nitrogen headspace, where used	Oxygen-reduction strategy	Container-process attribute rather than a conventional listed excipient
Container closure	Protects sterile solution and limits extractables	Major source of development and validation risk

A minimal excipient system is advantageous. Every additional excipient creates new risks involving degradation, toxicity, extractables, compatibility, osmolality, particulate formation, and regulatory justification.

What pH range is relevant?

Cisatracurium injection is an acidic formulation. The Nimbex label reports a pH range of approximately 3.25 to 3.65 for the injection.[1] A commercial developer should treat pH as a critical quality attribute rather than a simple manufacturing parameter because changes may affect degradation kinetics, potency, color, particulate generation, and compatibility after dilution.

The optimal pH target should be established through forced-degradation and stability studies. The formulation should not be moved toward physiological pH without evidence that the change improves the product sufficiently to justify higher development risk.

How should an excipient strategy be designed for cisatracurium?

The preferred strategy is a low-excipient, acidic, preservative-free aqueous formulation with a validated container-closure system.

What are the primary formulation objectives?

The formulation program should prioritize:

1. Chemical stability of cisatracurium.
2. Maintenance of assay and impurity specifications.
3. Sterility assurance and low visible and subvisible particulate levels.
4. Resistance to adsorption and interaction with the primary container.
5. Compatibility with common infusion diluents and administration sets.
6. Acceptable refrigerated and in-use stability.
7. Consistent delivery at low injectable volumes.
8. A commercially efficient manufacturing process.

The development team should evaluate pH, ionic strength, oxygen exposure, light exposure, freeze-thaw stress, agitation, and container-contact effects. The active ingredient’s degradation pathways should be mapped before selecting any alternative buffer or stabilizer.

Should a buffer be added?

A buffer is not automatically advantageous. The reference formulation uses benzenesulfonic acid rather than a conventional phosphate, citrate, acetate, or lactate buffer system.[1] Adding a buffer could improve pH control during manufacture or dilution, but it may also increase ionic strength, introduce precipitation risk, complicate compatibility, and create a materially different formulation for regulatory purposes.

A buffer may be justified if it provides a measurable stability or manufacturing benefit. The strongest case would involve improved pH control across the shelf life or better resilience to dilution and temperature excursions. Otherwise, retaining the simpler acidified-water system is more defensible.

Are preservatives commercially attractive?

Preservatives are generally unattractive for cisatracurium injection. A preservative-free, single-dose product aligns with hospital intravenous-use expectations and avoids exposure to benzyl alcohol, parabens, phenol, or other antimicrobial agents. Multidose packaging could reduce per-dose packaging cost, but it would introduce preservative qualification, multidose microbial challenge requirements, additional labeling limitations, and a higher clinical-use burden.

The likely commercial value of a preservative-free product exceeds the potential manufacturing savings from a multidose design.

What formulation patents protect cisatracurium besylate?

Cisatracurium is an old small-molecule injectable product. Foundational composition and product patents associated with early cisatracurium development are unlikely to provide meaningful current U.S. exclusivity because the relevant patent terms have generally expired or are near expiration based on statutory patent-term rules.[4]

The present competitive barrier is therefore more likely to be regulatory execution, manufacturing quality, supply reliability, and hospital contracting than active-ingredient patent protection.

What is the Orange Book status of cisatracurium?

Cisatracurium products marketed as approved generic injections are generally regulated as abbreviated new drug products. The FDA Orange Book records listed patents and regulatory exclusivities for approved products, but an applicant must review the current product-specific entries and associated patent certifications before filing.[5]

For an established injectable generic, the principal regulatory risks are usually:

• Product-specific bioequivalence or equivalence requirements.
• Sterility and aseptic-processing controls.
• Stability data under labeled storage conditions.
• Container-closure qualification.
• Manufacturing-site inspection readiness.
• Supply continuity and shortage reporting.

Cisatracurium does not create a biosimilar pathway. It is a chemically defined small molecule, so biosimilar approval requirements do not apply.

Are Paragraph IV challenges relevant?

Paragraph IV certification may be relevant only if a listed patent remains active for the specific reference product and product category. A generic applicant should evaluate the current Orange Book listing rather than assume that the absence of an obvious formulation patent eliminates certification obligations.[5]

For an old injectable product, the greater probability is that commercial entry will occur through ordinary ANDA approval without a major patent-litigation event. Any litigation risk would depend on the current listed patents, their expiration dates, and whether a branded or authorized-generic sponsor asserts them.

What formulation opportunities exist for cisatracurium?

Ready-to-administer syringes

A prefilled syringe could reduce preparation time and pharmacy compounding steps. The development case depends on:

• Syringe-material compatibility.
• Adsorption and leachables.
• Dose-volume accuracy.
• Stability in the filled syringe.
• Needle and connector compatibility.
• Protection from light and temperature excursions.
• Human-factors validation.

A prefilled syringe is most attractive for emergency intubation kits, operating-room carts, and intensive-care medication systems. The primary commercial challenge is the relatively small dose volume and the need to avoid confusion between concentrations.

Higher-concentration presentations

A higher-concentration product could reduce infusion volume and simplify administration where fluid restriction matters. The opportunity is strongest in intensive-care settings and in institutions using standardized neuromuscular-blocking protocols.

The risk is medication error. Concentration differentiation must be visible on the label, carton, vial, syringe, barcode, and electronic medication record. A higher-strength product should not be introduced without a clear clinical-use rationale and human-factors assessment.

Ready-to-use infusion bags

A premixed infusion bag could support prolonged administration and reduce pharmacy preparation. The commercial case is less certain than for vials or syringes because cisatracurium is often administered in controlled clinical environments where pharmacy or nursing staff can prepare diluted solutions.

A bag presentation would require extensive evaluation of:

• Diluent selection.
• Bag-film compatibility.
• Adsorption to tubing.
• Stability over the proposed in-use period.
• Microbial risk after connection.
• Pump compatibility.
• Shipping and storage economics.

Light-protective packaging

Light protection may improve product robustness if photodegradation is demonstrated. Amber glass, an overwrap, or an opaque secondary package may be preferable to adding a chemical stabilizer. Packaging changes can often address degradation without expanding the excipient system.

Improved temperature-excursion performance

Hospitals value products that tolerate short excursions outside refrigerated storage. A developer should quantify stability at controlled room temperature, elevated temperature, freeze-thaw conditions, and shipping vibration. If a product supports a longer room-temperature allowance than competitors, that attribute can improve wholesaler and hospital inventory management.

The claim must be supported by stability data and reflected precisely in labeling. Temperature-excursion performance is a commercial differentiator, not an assumed property.

How does cisatracurium compare with competing neuromuscular blockers?

Drug	Class	Typical commercial strength	Key excipient or formulation issue	Competitive position
Cisatracurium	Nondepolarizing, intermediate duration	Commonly 2 mg/mL	Acidic aqueous solution; refrigeration and compatibility	Attractive when organ-independent elimination is valued
Atracurium	Nondepolarizing, intermediate duration	Commonly 10 mg/mL	Similar Hofmann-elimination profile; formulation and supply competition	Direct pharmacologic substitute
Rocuronium	Nondepolarizing, intermediate duration	Commonly 10 mg/mL	Higher concentration and broad perioperative use	Strong operating-room competitor
Vecuronium	Nondepolarizing, intermediate duration	Powder for reconstitution in many markets	Reconstitution burden	Competes on clinical familiarity and cost
Succinylcholine	Depolarizing, short duration	Multiple injectable strengths	Distinct clinical profile and stability requirements	Substitute for rapid-sequence intubation

Cisatracurium’s product positioning is strongest where clinicians value predictable elimination, reduced reliance on hepatic or renal function, and an established ICU-use profile. Rocuronium has a stronger rapid-intubation and reversal-agent ecosystem. Atracurium is the closest formulation and pharmacology comparator.

What manufacturing and IP barriers affect commercial entry?

The active ingredient does not present the same patent barrier as a newly launched drug. Manufacturing remains difficult because the product is a sterile injectable with tight impurity and particulate requirements.

Which manufacturing controls matter most?

Key controls include:

• Active-ingredient identity, assay, and stereochemical composition.
• Control of related substances and degradation products.
• pH and osmolality.
• Bioburden before sterilizing filtration.
• Sterilizing-filter validation.
• Aseptic filling or validated terminal sterilization, depending on product design.
• Particulate control.
• Container-closure integrity.
• Extractables and leachables.
• Cold-chain performance.
• In-use and dilution stability.

The active ingredient’s stereochemical definition is also important. Cisatracurium is not interchangeable in development terms with an unrestricted atracurium mixture. The supplier qualification package must establish identity, purity, stereochemical profile, residual solvents, elemental impurities, and process-related impurities.

Is the excipient supply chain a major risk?

Benzenesulfonic acid and water for injection are broadly available. The higher supply risks are associated with:

• Qualified cisatracurium besylate API suppliers.
• Sterile injectable manufacturing capacity.
• Specialty glass vials and elastomeric closures.
• Cold-chain logistics.
• Backup fill-finish capacity.
• Hospital purchasing concentration.

A dual-source strategy for API and packaging is commercially valuable. A developer with a reliable U.S. or European fill-finish network may compete effectively even without a novel formulation patent.

What licensing and partnership opportunities exist?

The most realistic licensing opportunities involve manufacturing and commercialization rather than ownership of a new cisatracurium molecule.

Potential transaction structures include:

Opportunity	Likely counterparties	Commercial rationale
API supply agreement	Specialty API manufacturers	Reduces qualification and continuity risk
Contract fill-finish	Sterile injectable CDMOs	Avoids construction of an aseptic facility
Regional commercialization	Hospital-focused generic companies	Provides formulary access and contracting capacity
Prefilled-syringe platform license	Device and injectable developers	Accelerates differentiated presentation
Authorized-generic arrangement	Originator or established marketer	May improve launch access and supply credibility
Hospital group purchasing agreement	GPOs and integrated delivery networks	Supports volume-based procurement

Public product-level revenue for cisatracurium is generally not disclosed separately by manufacturers. Commercial exposure should therefore be modeled using unit volume, average selling price, contract concentration, shortage history, and share of operating-room and ICU demand rather than relying on brand-level revenue estimates.

When does cisatracurium lose exclusivity and what are the generic launch scenarios?

Cisatracurium is already a mature generic category in the United States. The relevant commercial question is not the loss of exclusivity but the structure of continued generic supply.

Scenario 1: Low-cost vial entrant

A conventional 2 mg/mL vial product can enter through an ANDA and compete primarily on price, availability, and GPO contracting. This is the lowest-risk formulation strategy but also the most exposed to price compression.

Scenario 2: Supply-reliability entrant

A company can differentiate through redundant API sourcing, domestic or nearshore fill-finish, and strong backorder performance. Hospitals may accept a modest price premium for reliable supply in a critical injectable category.

Scenario 3: Prefilled-syringe entrant

A prefilled syringe may support premium pricing if it reduces preparation time and medication errors. The product would require stronger device, human-factors, and stability packages.

Scenario 4: Higher-concentration or infusion presentation

A concentrated vial or premixed bag could target ICU and fluid-restricted use. The opportunity is commercially narrower and carries greater medication-safety and compatibility risk.

What is the geographic coverage and regulatory pathway?

The United States, European Union, Canada, Japan, and other regulated markets have established pathways for generic cisatracurium products. Requirements differ by jurisdiction, particularly for injectable equivalence, stability, container systems, and pharmacopoeial compliance.

In the United States, an ANDA is the normal route for a product matching the reference listed drug in active ingredient, dosage form, strength, route, and labeling, subject to FDA requirements.[5,6] A materially different formulation or delivery system may require a 505(b)(2) application rather than a standard ANDA.

In the European Union, a generic application under Article 10(1) may be appropriate for an equivalent product, while a hybrid application may be needed for certain differences in formulation, strength, or clinical use.[7]

Geographic expansion should begin with markets where the developer has:

• A qualified sterile manufacturing site.
• A validated cold-chain network.
• Local regulatory expertise.
• Hospital tender access.
• Reliable pharmacovigilance and shortage-reporting infrastructure.

How strong is the cisatracurium commercial and patent estate?

The patent estate is weak as a source of current exclusivity because cisatracurium is an established small-molecule injectable. The commercial estate can still be strong if it includes differentiated packaging, supply contracts, manufacturing capacity, regulatory approvals, and hospital formulary access.

Estate component	Current strategic value
Core active-ingredient patents	Low for new U.S. exclusivity
Conventional vial formulation	Low differentiation; high price pressure
Novel excipient system	Moderate if stability or usability improves
Prefilled syringe	Moderate to high if clinically and operationally useful
Premixed infusion product	Moderate, with higher development risk
Manufacturing process know-how	High where it improves yield, impurity control, or supply continuity
Hospital contracts	High but difficult to sustain
Device and packaging patents	Potentially meaningful for differentiated presentations
Biosimilar protection	Not applicable

Key Takeaways

• Cisatracurium besylate is a mature sterile injectable with limited current active-ingredient exclusivity.
• The reference formulation is a simple acidic aqueous solution using water for injection and benzenesulfonic acid.
• Preservative-free formulations are commercially preferable for single-dose intravenous use.
• The strongest opportunities are ready-to-use syringes, reliable 2 mg/mL vial supply, higher-concentration presentations, and selected premixed infusion products.
• Excipient expansion should be limited because added buffers, stabilizers, or preservatives increase regulatory and compatibility risk.
• Manufacturing quality, API redundancy, cold-chain performance, container closure, and hospital contracting are more important than conventional molecule patents.
• Cisatracurium has no biosimilar risk because it is a small-molecule drug.
• A conventional vial entrant faces price compression. A differentiated presentation can support better margins but requires additional device, stability, and human-factors evidence.

FAQs

Is cisatracurium besylate a biologic?

No. Cisatracurium besylate is a chemically synthesized small-molecule drug. Generic applicants use abbreviated small-molecule pathways, not biosimilar pathways.

Can cisatracurium injection contain benzyl alcohol?

A preservative-containing formulation is technically possible only with supporting safety, stability, and regulatory data. The commercially preferred design is generally a preservative-free single-dose product.

Is benzenesulfonic acid an active ingredient?

No. Cisatracurium besylate is the active pharmaceutical ingredient. Benzenesulfonic acid is an inactive acidifying or pH-control component in the injectable formulation.[1,3]

Can cisatracurium be formulated at physiological pH?

It can be investigated, but a higher-pH formulation would require evidence that it improves stability, compatibility, or clinical use enough to offset development risk. The established product is acidic.

What is the best commercial presentation for a new cisatracurium product?

A supply-reliable, preservative-free 2 mg/mL vial is the lowest-risk entry. A prefilled syringe offers greater differentiation, while a higher-strength or premixed presentation offers narrower opportunities with higher regulatory and medication-safety requirements.

References

1. U.S. Food and Drug Administration. (2023). Nimbex (cisatracurium besylate) injection, prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/

2. Stenlake, J. B., Waigh, R. D., Urwin, J., Dewar, G. H., & Coker, G. G. (1983). Atracurium: A new competitive neuromuscular blocking agent. British Journal of Anaesthesia, 55(1), 91S-94S.

3. National Library of Medicine. (2024). DailyMed: Cisatracurium besylate injection. https://dailymed.nlm.nih.gov/dailymed/

4. U.S. Patent and Trademark Office. (2024). Patent term calculator and patent term guidance. https://www.uspto.gov/patents/laws/patent-term-calculator

5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

6. U.S. Food and Drug Administration. (2024). Abbreviated new drug application process. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda

7. European Medicines Agency. (2024). Generic and hybrid medicines. https://www.ema.europa.eu/en/human-regulatory-overview/marketing-authorisation/generic-hybrid-medicines