List of Excipients in Branded Drug ERTAPENEM

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
ENDO USA Inc	ERTAPENEM	ertapenem sodium	42023-221	SODIUM BICARBONATE
ENDO USA Inc	ERTAPENEM	ertapenem sodium	42023-221	SODIUM HYDROXIDE

Generic Drugs Containing ERTAPENEM

Company	Ingredient	NDC	Excipient
Hikma Pharmaceuticals USA Inc	ertapenem sodium	0143-9429	SODIUM BICARBONATE
Hikma Pharmaceuticals USA Inc	ertapenem sodium	0143-9429	SODIUM HYDROXIDE
Hospira Inc	ertapenem	0409-3510	SODIUM BICARBONATE

What are the Most Frequently-Used Excipients in ERTAPENEM?

# Of NDCs	Excipient
13	SODIUM BICARBONATE
13	SODIUM HYDROXIDE

Ertapenem Excipient Strategy and Commercial Opportunities

Last updated: August 17, 2026

Ertapenem is a mature, genericized carbapenem antibiotic with limited opportunity for conventional composition-of-matter exclusivity. Commercial value is concentrated in formulation execution: reconstitution time, room-temperature stability, ready-to-use delivery, reduced preparation errors, outpatient administration, and differentiated global presentations. The reference product, INVANZ, is a lyophilized ertapenem sodium powder for intravenous or intramuscular administration. Its core excipient system is relatively simple, creating room for lifecycle products but also imposing a high evidentiary burden for any meaningful formulation change.

What is the current formulation of ertapenem?

Ertapenem is supplied primarily as ertapenem sodium for injection in single-dose vials containing the equivalent of 1 g ertapenem. The US reference product uses sodium bicarbonate as a formulation excipient, with sodium hydroxide used for pH adjustment. The product is reconstituted before administration and is not compatible with dextrose-containing diluents under the labeled conditions.

Attribute	Reference product profile
Active ingredient	Ertapenem sodium
Dose strength	1 g ertapenem per vial
Dosage form	Sterile lyophilized powder
Administration	Intravenous infusion or intramuscular injection
Key excipient	Sodium bicarbonate
pH adjustment	Sodium hydroxide
IV diluent	0.9% sodium chloride
IM diluent	1% lidocaine hydrochloride without epinephrine
Primary use settings	Hospital, emergency, outpatient parenteral antimicrobial therapy
Regulatory status	FDA-approved antibacterial drug; generic products marketed in the U.S.

The reference formulation uses lyophilization to preserve ertapenem stability during storage. The formulation contains no conventional preservative because the vial is intended for single-dose use. The sodium content and pH profile are relevant for hospitals treating patients with fluid, renal, or electrolyte constraints. [1]

What excipients are used in ertapenem injection?

The principal excipient strategy is based on alkalinity control and solid-state stabilization rather than a complex matrix of polymers, surfactants, or preservatives.

Sodium bicarbonate

Sodium bicarbonate is the principal listed formulation excipient in the reference product. It supports the alkaline environment required for ertapenem stability during manufacture and storage. The excipient also contributes to the sodium load of the finished product.

The commercial advantage of sodium bicarbonate is regulatory familiarity and manufacturing simplicity. Its disadvantages include sodium exposure, the need for tight pH control, and potential limitations in developing a lower-sodium or more patient-specific product.

Sodium hydroxide

Sodium hydroxide is used to adjust formulation pH. Its quantity is generally process-dependent and may not appear in the same way as a bulk excipient in commercial labeling. pH control is a critical quality attribute because ertapenem is sensitive to degradation under unsuitable conditions.

Lidocaine hydrochloride for intramuscular administration

For IM administration, the label permits reconstitution with 1% lidocaine hydrochloride without epinephrine. Lidocaine is a diluent rather than a core lyophilized excipient. Its purpose is to reduce injection-site discomfort.

An IM presentation that incorporates a pain-reducing diluent, prefilled syringe, or integrated reconstitution system could create commercial differentiation, but the product would require careful assessment of local tolerability, compatibility, preservative content, and device performance.

Sodium chloride for intravenous infusion

For IV use, ertapenem is reconstituted and diluted in 0.9% sodium chloride. Dextrose-containing solutions are not recommended because of compatibility and stability concerns. This restriction affects pharmacy workflow and can limit flexibility in patients requiring glucose-containing fluids.

What formulation patents could protect ertapenem products?

Ertapenem’s active pharmaceutical ingredient is no longer a practical source of new broad exclusivity in the United States. A new product would need to rely on formulation, device, manufacturing, or use claims.

Potential claim categories include:

Claim category	Commercial objective	Patent strength
Low-sodium composition	Reduce sodium burden	Moderate if stability and performance are unexpected
Alternative buffer system	Improve stability or compatibility	Moderate to weak without comparative data
Faster reconstitution	Reduce pharmacy labor and administration delays	Moderate if linked to a defined particle or cake structure
Ready-to-use solution	Eliminate reconstitution	Moderate to strong if long-term stability is demonstrated
Dual-chamber container	Separate drug and diluent until use	Moderate, with device and formulation claim combinations
Improved lyophilized cake	Reduce vial-to-vial variability	Moderate
Extended room-temperature stability	Support transport and outpatient care	Stronger if the stability profile is materially better
Low-volume IM formulation	Reduce injection burden	Moderate
Pediatric or renal-use presentation	Improve dosing and handling	Usually vulnerable to obviousness and method-of-use challenges
Manufacturing process	Improve yield, impurity control, or sterility assurance	Strong when process parameters are technically specific

A patent directed only to replacing sodium bicarbonate with another conventional buffer would face substantial obviousness risk. The strongest formulation cases would connect the excipient choice to an unexpected result, such as a large improvement in reconstituted stability, reduced impurity formation, improved cake integrity, or compatibility with a ready-to-use container.

How does ertapenem’s patent and exclusivity status affect commercial strategy?

Ertapenem is a mature small-molecule product. Its United States regulatory exclusivity has expired, and generic ertapenem sodium for injection products are marketed. The commercial opportunity therefore depends on product differentiation rather than protection of the active ingredient.

Exclusivity category	Ertapenem position
New chemical entity exclusivity	Expired
Core composition patent	Expired or no longer commercially controlling
Pediatric exclusivity	Historical exclusivity, expired
Orange Book market exclusivity	No current reference-product exclusivity expected
Generic availability	Yes
Biosimilar pathway	Not applicable
Main remaining protection opportunity	Formulation, device, process, or narrow method claims

The FDA Orange Book remains the primary source for current listed patents and exclusivity status. A sponsor evaluating a new ertapenem presentation should conduct a current Orange Book review and a separate patent-family search because many commercial barriers may arise outside listed-drug patents, particularly from device, manufacturing, or packaging claims. [2]

What is the Orange Book status of ertapenem?

The reference product is INVANZ, originally approved by the FDA in 2001. The product is associated with ertapenem sodium for injection. Current commercial activity is dominated by abbreviated new drug application products rather than a protected branded market.

An ANDA sponsor generally must address applicable listed patents through certification or a statement concerning patent expiration. Historical Paragraph IV activity was relevant during the generic-entry period, but the product’s principal patent barriers have expired. Current competition is therefore more likely to involve ANDA approval timing, manufacturing capacity, procurement contracts, and supply reliability than unresolved core patent litigation.

Which companies compete in the ertapenem market?

The market includes the originator, generic injectable manufacturers, contract manufacturers, hospital suppliers, and distributors. The competitive set can change by country and tender cycle.

Commercial differentiation typically comes from:

• vial price and annual contract terms;
• reliable sterile manufacturing capacity;
• availability of 1 g single-dose vials;
• regional regulatory approvals;
• supply continuity during antibiotic shortages;
• packaging suitable for hospital pharmacy operations;
• compatibility with outpatient infusion providers;
• technical support for reconstitution and administration.

The originator’s brand retains value in some institutions because of familiarity and procurement preference, but generic products compete directly on price. A differentiated ertapenem product needs a measurable workflow or clinical-use advantage to command a premium.

What commercial opportunities exist for ertapenem excipient innovation?

Ready-to-use ertapenem solution

A stable ready-to-use solution could eliminate vial reconstitution, reduce pharmacy labor, and lower preparation errors. The main technical barrier is chemical stability in the liquid state. The reference product’s lyophilized presentation indicates that long-term liquid stability is a central development challenge.

A ready-to-use product would need to address:

• degradation during refrigerated and room-temperature storage;
• container closure compatibility;
• extractables and leachables;
• particulate control;
• sterility over the labeled shelf life;
• infusion-container compatibility;
• transport temperature excursions.

A product with 24-hour or 72-hour post-opening stability would have value in hospitals and outpatient antimicrobial therapy, although its commercial premium would depend on total pharmacy cost savings.

Dual-chamber or integrated reconstitution system

A dual-chamber vial, syringe, cartridge, or infusion bag could separate ertapenem from its diluent until administration. This approach would preserve the lyophilized drug while removing manual transfer steps.

The main opportunity is operational rather than pharmacological. A dual-chamber system could reduce preparation time and contamination risk. It could also support home-based administration if the device is intuitive and does not require specialized pharmacy equipment.

The device may generate stronger intellectual-property protection than a conventional excipient substitution. Protection could include chamber architecture, seal design, activation mechanism, reconstitution sequence, and a drug-device combination.

Improved lyophilized cake

A reformulated cake that dissolves faster or produces fewer particulates could improve pharmacy throughput. Candidate development variables include:

• buffer concentration;
• bulking agents;
• collapse temperature;
• primary drying conditions;
• cake pore structure;
• vial fill volume;
• residual moisture;
• reconstitution agitation requirements.

This opportunity is technically feasible but commercially narrower. The product must demonstrate a meaningful reduction in reconstitution time or preparation variability compared with generic vials.

Lower-sodium formulation

Sodium bicarbonate is a logical target for reformulation. A lower-sodium product could appeal to patients with fluid or sodium restrictions, although the relevance depends on dose, treatment duration, and the sodium content of the final infusion.

The regulatory case would require more than a lower sodium number. The sponsor would need to establish equivalent antimicrobial performance, stability, impurity profile, reconstitution behavior, and administration compatibility. The commercial value may be highest in prolonged outpatient treatment and specialized hospital populations.

Alternative IM presentation

Ertapenem’s IM route creates an opportunity for a lower-volume or lower-pain presentation. A prefilled diluent device, integrated lidocaine system, or optimized concentration could improve administration.

The principal barriers are injection-site tolerability and formulation limits. Increasing concentration may reduce volume but can increase osmolality, local irritation, or precipitation risk. The product would need a clear usability advantage over the current vial-plus-diluent approach.

What manufacturing and intellectual-property barriers affect ertapenem?

Ertapenem is a sterile injectable antibiotic, so manufacturing capability is a major barrier even without active composition patents.

Critical manufacturing requirements include:

1. Control of ertapenem degradation products and related substances.
2. Reproducible sterile filtration or aseptic processing.
3. Lyophilization cycle control.
4. Container closure integrity.
5. Low particulate burden.
6. Validated reconstitution performance.
7. Control of residual moisture.
8. Stability under temperature excursions.
9. Reliable API supply.
10. Compliance with FDA current good manufacturing practice requirements.

Process patents may protect crystallization, purification, drying, impurity reduction, or scale-up methods. These claims can affect generic API sourcing even when the finished-drug formulation is unprotected. A sponsor should also review patents covering vial systems, ready-to-use bags, transfer devices, and antimicrobial packaging.

What generic entry risks exist for differentiated ertapenem products?

Generic entry risk is high for a conventional lyophilized vial. The product has an established route, strength, administration method, and reference formulation. A new entrant using the same basic presentation would compete primarily on price and supply.

Risk is lower, but not eliminated, for:

• ready-to-use products;
• dual-chamber delivery systems;
• low-sodium formulations;
• extended-stability presentations;
• integrated IM administration systems.

The strength of protection depends on whether the claims cover a technically necessary feature or a readily substitutable design. A competitor may avoid a device patent by changing chamber geometry, using a different diluent container, or reverting to a conventional vial. Formulation patents are more durable when they require a narrow combination of excipient concentrations, pH, moisture, impurity limits, and stability results.

What patent litigation and settlement issues affect ertapenem?

No active core-patent barrier is expected to prevent ordinary generic ertapenem entry in the United States. Historical litigation associated with generic filings would be most relevant to the timing of past market entry, not to a current branded exclusivity period.

Future disputes would more likely concern:

• infringement of formulation patents;
• device patents for dual-chamber systems;
• process patents covering API manufacture;
• trade-secret claims involving sterile manufacturing;
• abbreviated new drug application patent certifications;
• settlement terms restricting launch of a reformulated product.

A sponsor commercializing a new ertapenem presentation should separate three risks: freedom to operate, validity of its own patent claims, and the likelihood that a generic can design around the claims.

How does ertapenem compare with other carbapenem products?

Product	Main route	Typical commercial differentiator	Excipient opportunity
Ertapenem	IV and IM	Once-daily dosing and outpatient use	Ready-to-use delivery, low sodium, IM usability
Meropenem	IV	Broad hospital use and flexible dosing	Stability after reconstitution, premix systems
Imipenem/cilastatin	IV and IM	Established broad-spectrum use	Combination stability and administration convenience
Doripenem	IV	Hospital-focused carbapenem	Limited commercial opportunity after market contraction

Ertapenem has a specific advantage for once-daily administration, which supports outpatient antimicrobial therapy. Its main formulation disadvantage is the need for reconstitution and dilution. This makes delivery-system innovation more commercially relevant than adding conventional excipients to the existing powder.

Key Takeaways

• Ertapenem is a mature genericized carbapenem with no meaningful remaining composition-of-matter exclusivity in the U.S.
• The reference formulation uses a lyophilized ertapenem sodium powder with sodium bicarbonate and pH adjustment using sodium hydroxide.
• The strongest commercial opportunities are ready-to-use solutions, dual-chamber systems, improved lyophilized cakes, lower-sodium formulations, and improved IM presentations.
• A simple buffer substitution is unlikely to create strong patent protection without unexpected stability or performance data.
• Device and formulation claims can provide more defensible lifecycle protection than conventional excipient claims.
• Generic competition is intense for standard 1 g vials. Premium positioning requires measurable reductions in preparation time, contamination risk, storage burden, or administration discomfort.
• Biosimilar risk does not apply because ertapenem is a small-molecule antibiotic.
• Sterile manufacturing, lyophilization, impurity control, and supply reliability are material commercial barriers even after patent expiry.
• The most attractive target is a differentiated, pharmacy-efficient presentation aligned with once-daily outpatient treatment.

FAQs About Ertapenem Excipients and Commercialization

Can ertapenem be formulated as a premixed infusion bag?

Yes, but the liquid formulation would need to demonstrate adequate chemical and physical stability, sterility, container compatibility, and transport robustness. The main development barrier is the stability of ertapenem in solution over the desired shelf life.

Does ertapenem require a preservative?

The conventional single-dose vial does not require a preservative. A multidose or reusable presentation would create additional preservative efficacy, compatibility, and regulatory requirements.

Is a low-sodium ertapenem product clinically differentiated?

Potentially. The value would be greatest in patients receiving repeated doses or those with sodium and fluid restrictions. The sponsor would need to establish that sodium reduction does not compromise stability, impurity control, or administration performance.

Could a patent protect a faster-reconstituting ertapenem vial?

Yes, if the claim covers a specific formulation or lyophilized structure and the sponsor demonstrates a meaningful, non-obvious improvement. A general claim to faster dissolution would face validity and enablement challenges.

Is there a strong opportunity for oral ertapenem?

An oral product would represent a major reformulation rather than an excipient optimization. Ertapenem has poor oral suitability, so an oral version would likely require a prodrug, absorption-enhancement technology, or a new delivery platform. Its development risk would be materially higher than that of an improved injectable presentation.

References

1. U.S. Food and Drug Administration. (2023). INVANZ (ertapenem for injection) prescribing information. Merck Sharp & Dohme LLC.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

3. U.S. Food and Drug Administration. (2001). FDA approves INVANZ for treatment of bacterial infections. FDA.

4. U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs database. FDA.

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