List of Excipients in Branded Drug ONFI

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Lundbeck Pharmaceuticals LLC	ONFI	clobazam	67386-314	LACTOSE MONOHYDRATE
Lundbeck Pharmaceuticals LLC	ONFI	clobazam	67386-314	MAGNESIUM STEARATE
Lundbeck Pharmaceuticals LLC	ONFI	clobazam	67386-314	SILICON DIOXIDE
Lundbeck Pharmaceuticals LLC	ONFI	clobazam	67386-314	STARCH, CORN
Lundbeck Pharmaceuticals LLC	ONFI	clobazam	67386-314	TALC

Last updated: August 2, 2026

ONFI is an oral clobazam product whose commercial differentiation depends more on liquid formulation performance, pediatric acceptability, dosing accuracy, and supply reliability than on the active ingredient. The strongest excipient opportunities are taste-masked oral suspensions, preservative systems, age-appropriate dosage forms, and formulation designs that reduce sedimentation and dosing error. Clobazam is an established small molecule, so biosimilar risk is irrelevant and generic competition is the primary commercial threat.

ONFI Excipient Strategy and Commercial Opportunities for Clobazam Oral Suspension

What is ONFI and how is it supplied?

ONFI is the U.S. brand name for clobazam, a 1,5-benzodiazepine indicated as adjunctive treatment for seizures associated with Lennox-Gastaut syndrome in patients age 2 years and older. The FDA approved ONFI tablets and an oral suspension in October 2011. The marketed strengths include 10 mg and 20 mg tablets and a 2.5 mg/mL oral suspension.[1]

The oral suspension has particular commercial relevance because Lennox-Gastaut syndrome is a pediatric and adult disorder in which swallowing difficulty, caregiver administration, and dose titration affect product selection. The liquid formulation permits weight-based dosing and may be used when patients cannot reliably swallow tablets.

Product attribute	ONFI oral suspension
Active ingredient	Clobazam
Strength	2.5 mg/mL
Dosage form	Oral suspension
Primary indication	Lennox-Gastaut syndrome
Patient population	Adults and pediatric patients age 2 years and older
Administration	Oral, measured dose
Key formulation needs	Taste masking, physical stability, preservative protection, dosing accuracy
Regulatory pathway for competitors	Abbreviated New Drug Application, or potentially 505(b)(2) for differentiated products

ONFI is not a biologic. Biosimilar substitution is therefore not relevant. Competition is expected to come from generic clobazam tablets, generic oral suspensions, compounded products, and differentiated oral dosage forms.

What excipients are used in ONFI oral suspension?

The ONFI prescribing information identifies excipients associated with the oral suspension, including polysorbate 80, sorbitan monooleate, xanthan gum, sodium benzoate, citric acid, sodium citrate, sucralose, and flavoring components.[1]

Their functional roles are summarized below.

Excipient or excipient class	Likely formulation function	Commercial significance
Polysorbate 80	Wetting, dispersion, and emulsion stabilization	Supports uniform distribution of clobazam and flavor components
Sorbitan monooleate	Surfactant and emulsion stabilizer	Helps control interfacial behavior in the liquid system
Xanthan gum	Suspending and viscosity-building agent	Limits sedimentation and supports dose uniformity
Sodium benzoate	Preservative	Helps control microbial growth in a multidose aqueous product
Citric acid and sodium citrate	Buffer system and pH control	Supports chemical stability, preservative performance, and palatability
Sucralose	High-intensity sweetener	Reduces bitterness and improves pediatric acceptability
Flavoring	Taste and odor masking	Important for chronic pediatric use and caregiver acceptance

The formulation is not a simple solution. It is a structured suspension that must maintain dose uniformity throughout storage and use. The combination of surfactants and xanthan gum suggests a design focused on wetting clobazam particles, controlling sedimentation, and allowing redispersion before dosing.

What excipient strategy is most important for ONFI competitors?

The commercial priority is a robust taste-masked suspension that remains physically uniform across the labeled shelf life and during repeated home use.

Taste masking

Clobazam is a centrally acting benzodiazepine and may present an unpleasant taste profile. Sucralose and fruit flavoring address sweetness and sensory masking, but a generic sponsor cannot assume that the same flavor system will perform identically with a different clobazam particle size, polymorph, or excipient supplier.

Potential improvements include:

• More effective flavor systems for bitterness and medicinal aftertaste.
• Dual sweetener systems that reduce excessive sweetness.
• Ion-exchange resins or polymeric taste-masking approaches.
• Coated clobazam particles that reduce immediate contact with taste receptors.
• Flavor systems designed for children who reject conventional fruit flavors.

Taste masking creates an opportunity for a differentiated 505(b)(2) product, but a formulation that materially changes drug release, absorption, or dose uniformity could trigger additional clinical and regulatory requirements.

Suspension stability

Xanthan gum is widely used in oral suspensions, but its performance depends on grade, hydration, shear history, electrolyte concentration, pH, and interaction with surfactants. A substitute formulation must control:

• Sedimentation rate.
• Caking and compact sediment formation.
• Redispersion time.
• Viscosity during pouring or syringe withdrawal.
• Dose uniformity after storage and repeated shaking.
• Stability under temperature excursions.

A high-viscosity product may improve suspension stability but create a poor patient experience, inaccurate syringe withdrawal, or excessive product retention in the bottle. A low-viscosity product may be easier to administer but more vulnerable to rapid sedimentation.

The best commercial design is not the thickest suspension. It is a suspension that redistributes quickly with ordinary shaking and delivers a consistent dose through the intended oral syringe.

Preservative system

Sodium benzoate supports multidose microbial protection. The preservative strategy must be evaluated against pH, container closure, microbial challenge results, and the presence of surfactants or flavor oils.

Competitive products may seek preservative-free positioning, but that approach creates technical and packaging burdens. A preservative-free multidose suspension may require:

• Unit-dose packaging.
• Sterile or aseptic manufacturing.
• A more restrictive in-use period.
• Higher packaging cost.
• Greater caregiver handling complexity.

For a chronic antiseizure product, a conventional preserved multidose bottle is likely to remain commercially attractive unless the target population has a specific sensitivity or a strong preference for preservative-free products.

pH and buffer optimization

Citric acid and sodium citrate provide pH control. A competitor can explore buffer concentration and target pH to balance:

• Clobazam chemical stability.
• Preservative effectiveness.
• Flavor performance.
• Excipient compatibility.
• Container compatibility.
• Patient tolerability.

Buffer optimization can generate formulation patent claims, but the scope may be narrow if the formulation differs only by routine pH adjustment. Stronger intellectual-property positions are more likely when pH is linked to unexpected stability, improved dose uniformity, reduced degradation, or a distinct delivery profile.

What formulations are protected by ONFI-related intellectual property?

The core clobazam molecule is old, and active-ingredient composition patents are not expected to provide meaningful current exclusivity. Commercial protection is more likely to involve formulation, method-of-use, manufacturing, or regulatory exclusivity rights.

Potentially relevant protection categories include:

1. Oral suspension compositions containing clobazam and specified suspending or wetting agents.
2. Methods of treating Lennox-Gastaut syndrome with defined clobazam dosing regimens.
3. Pediatric dosing methods and weight-based titration.
4. Taste-masked clobazam particles or coated drug products.
5. Container and dosing-device combinations.
6. Manufacturing processes that improve suspension uniformity or control particle-size distribution.

A patent analyst should distinguish between a patent being listed in the FDA Orange Book and a patent being enforceable against a particular generic. Orange Book listing, claim scope, expiration, terminal disclaimers, pediatric extensions, and litigation history must be reviewed together.[2]

No current patent number, expiration date, or active Orange Book listing should be treated as controlling without a live review of the FDA Orange Book and USPTO records. A product-specific freedom-to-operate analysis based only on the ONFI label would be incomplete.

When does ONFI lose exclusivity?

ONFI’s principal exclusivity has already expired. The FDA approved the product in 2011, but clobazam was not a new molecular entity in the conventional sense. The commercial exclusivity period was therefore not equivalent to the five-year NCE exclusivity applicable to a new active ingredient. Any three-year exclusivity associated with the approval’s clinical investigations would have ended years ago.[1,3]

The current market is governed primarily by patent status and generic approval activity rather than FDA exclusivity. FDA approval of generic clobazam products demonstrates that the active ingredient and at least some dosage forms are open to ANDA competition.[4]

Exclusivity issue	ONFI assessment
New molecular entity exclusivity	Not the principal protection for ONFI
Three-year clinical investigation exclusivity	Historical, expired
Orphan-drug exclusivity	Not the principal basis of ONFI protection
Biosimilar exclusivity	Not applicable
Generic competition	Commercially relevant
Formulation patent risk	Must be checked against current Orange Book and patent records

What is the Orange Book status of ONFI?

The Orange Book is the controlling FDA source for listed patents and therapeutic-equivalence information for approved drug products.[2] ONFI’s commercial exposure should be assessed separately for tablets and oral suspension because a patent or regulatory issue affecting one dosage form may not block the other.

The critical Orange Book questions are:

• Whether ONFI has current listed patents.
• Whether those patents cover the oral suspension, tablets, methods of use, or multiple categories.
• Whether any patents have expired or been delisted.
• Whether generic applicants have submitted Paragraph IV certifications.
• Whether FDA approval dates for generic tablets and suspensions differ.
• Whether a generic applicant has received a 30-month stay from patent litigation.

A Paragraph IV certification is a statement that a listed patent is invalid, unenforceable, or will not be infringed by the proposed generic. It can trigger patent litigation within 45 days of notice and may delay approval under the Hatch-Waxman framework.[5]

Which companies are challenging ONFI and what generic entry risks exist?

The relevant challengers are manufacturers filing ANDAs for clobazam tablets or oral suspension. The commercial threat differs by dosage form.

Tablet competition

Tablet competition is technically simpler. Generic sponsors can use conventional excipients, standard solid-dose manufacturing, and established bioequivalence pathways. Price erosion may be faster because multiple manufacturers can enter without solving suspension-specific problems.

Oral suspension competition

Oral suspension competition has higher technical execution risk. A generic sponsor must demonstrate pharmaceutical equivalence and bioequivalence while controlling:

• Particle-size distribution.
• Sedimentation behavior.
• Redispersion.
• Assay uniformity.
• Preservative effectiveness.
• Container compatibility.
• Dosing-device accuracy.
• In-use stability.

These requirements create opportunities for manufacturing and formulation barriers. They do not automatically prevent approval. A well-funded generic manufacturer with suspension experience can overcome them, especially when the product has established FDA standards and a defined reference listed drug.

How can excipients create commercial opportunities beyond a generic ONFI copy?

The most attractive opportunities are differentiated products that solve adherence or administration problems.

Ready-to-use unit-dose suspension

Unit-dose oral syringes or sachets could reduce caregiver measurement error and contamination risk. The drawbacks are higher packaging costs, greater shipping volume, and more complicated manufacturing.

Improved oral syringe system

A calibrated oral syringe designed around the 2.5 mg/mL concentration could improve dose accuracy. A sponsor could seek device-related claims or pursue human-factors differentiation. The commercial value is strongest in pediatric use and in patients requiring small dose adjustments.

Sprinkle or orally disintegrating dosage form

Clobazam could be developed in an orally disintegrating tablet, granule, or sprinkle product for patients who cannot swallow conventional tablets. Excipients would need to address rapid disintegration, taste masking, moisture protection, and dose flexibility.

Lower-sugar or sugar-free formulation

ONFI already uses sucralose rather than a conventional caloric sugar sweetener. Future products could emphasize reduced excipient burden, dental considerations, or compatibility with patients who require controlled carbohydrate intake.

Preservative-free packaging

A preservative-free product could target patients with preservative sensitivity, but it would likely require unit-dose packaging or a validated short in-use period. This is a higher-cost strategy and should be supported by a clear clinical or caregiver benefit.

Pediatric flavor platform

A platform using interchangeable flavors could support lifecycle management across clobazam strengths or other chronic pediatric medicines. The intellectual-property value would depend on measurable improvement in acceptability, stability, or adherence rather than flavor selection alone.

How strong is the ONFI patent estate?

The estate is likely weaker around the clobazam molecule and stronger, if any enforceable rights remain, around formulation and method-of-use claims. The main risk factors are:

Risk factor	Assessment
Active-ingredient patent	Low relevance because clobazam is an established molecule
Tablet formulation	Moderate generic exposure
Oral suspension formulation	Higher technical barrier than tablets
Method-of-use claims	Potentially relevant if listed and not carved out
Taste-masking claims	Potential lifecycle-management opportunity
Device claims	Possible commercial differentiation
Manufacturing patents	Could affect specific processes but may not block all alternatives
Biosimilar substitution	Not applicable

A formulation patent is commercially valuable only if its claims cover a feature that generic sponsors cannot readily design around. Broad claims covering clobazam plus conventional excipients may face validity and obviousness challenges. Narrow claims tied to unexpected stability, taste masking, dose uniformity, or device performance may be more defensible but easier to avoid through formulation changes.

What regulatory status applies to ONFI and future excipient products?

ONFI is an FDA-approved prescription drug. A conventional generic suspension would normally proceed through an ANDA by demonstrating pharmaceutical equivalence and bioequivalence to the reference listed drug.[4] A product with a clinically meaningful formulation or delivery difference may require a 505(b)(2) application rather than an ANDA.

The regulatory pathway affects commercial timing:

• ANDA: lower development cost, narrower differentiation, greater price competition.
• 505(b)(2): higher development burden, broader formulation or delivery claims, potential for differentiated labeling.
• New dosage form with limited clinical relevance: may still face FDA requirements for comparative bioavailability, safety, or human-factors evidence.
• Compounded suspension: may fill local access gaps but generally lacks the manufacturing consistency and commercial reach of an FDA-approved product.

How does ONFI compare with competing clobazam products?

Attribute	ONFI	Generic clobazam tablets	Generic clobazam suspension	Differentiated 505(b)(2) product
Primary value	Established branded suspension and tablets	Low-cost substitution	Lower-cost liquid alternative	Administration or adherence improvement
Excipient differentiation	Taste, suspension, preservation	Usually limited	Required for equivalence	Potentially substantial
Patient fit	Pediatric and swallowing-challenged patients	Patients able to swallow tablets	Liquid-dose patients	Patients needing improved convenience
Price pressure	High after generic entry	Highest	High, but technical barriers may limit entrants	Moderate if clinical value is clear
Patent opportunity	Legacy formulation and method claims	Design-around risk	Suspension and device claims	Stronger lifecycle-management potential
Biosimilar risk	None	None	None	None

What revenue exposure does ONFI create?

Revenue exposure is concentrated in the oral suspension franchise because the liquid product has greater administration value than a standard tablet but also faces substitution risk once equivalent suspensions are available.

The principal erosion scenarios are:

1. Generic tablets capture patients who can swallow solid dosage forms.
2. Generic suspension entrants reduce liquid pricing.
3. Payers require generic substitution or impose prior authorization on branded ONFI.
4. Compounded clobazam fills supply gaps but creates quality and consistency concerns.
5. A differentiated product captures pediatric and caregiver segments through better dosing or taste performance.

The strongest defense is a product attribute that affects treatment execution, not only a different excipient list. Dosing accuracy, redispersion, taste acceptability, and packaging convenience are more commercially meaningful than routine changes in buffer or preservative selection.

Key Takeaways

• ONFI is clobazam, an established small-molecule antiseizure drug approved for Lennox-Gastaut syndrome.
• The oral suspension uses a functional excipient system built around surfactants, xanthan gum, sodium benzoate, citrate buffering, sucralose, and flavoring.
• The main technical risks are taste masking, sedimentation, redispersion, preservative protection, and dosing accuracy.
• Biosimilar risk is irrelevant; generic tablets and suspensions are the principal threats.
• The best commercial opportunities are improved pediatric flavoring, oral syringes, unit-dose packaging, orally disintegrating or sprinkle dosage forms, and preservative-free presentations.
• Patent value is more likely to reside in formulation, method-of-use, device, or manufacturing claims than in the clobazam molecule.
• Current Orange Book listings, Paragraph IV certifications, patent expiration dates, and litigation status require product-specific verification before investment or launch decisions.

FAQs

Can excipient changes support a new clobazam patent?

Yes. Patentability is stronger when the excipient combination produces a demonstrated technical effect, such as improved taste masking, stability, dose uniformity, or redispersion. Routine substitution of one sweetener, buffer, or preservative is more vulnerable to obviousness challenges.

Is ONFI oral suspension suitable for a preservative-free reformulation?

Potentially, but a preservative-free multidose product would require a different microbial-control and packaging strategy. Unit-dose packaging is the most direct commercial route, although it increases cost and distribution complexity.

What is the most difficult quality attribute for a generic clobazam suspension?

Physical dose uniformity after storage and ordinary patient handling is likely to be one of the most important challenges. The product must redisperse consistently without becoming excessively viscous or difficult to withdraw through an oral syringe.

Can a new clobazam flavor avoid generic substitution?

Flavor alone usually provides limited protection against substitution. A product is more defensible when flavor is integrated with a distinct formulation, device, labeling claim, or demonstrated adherence benefit.

Does ONFI have biosimilar competition?

No. Clobazam is a small molecule. Competition comes through generic-drug pathways, not biosimilar pathways.

References

1. U.S. Food and Drug Administration. (2023). ONFI (clobazam) tablets and oral suspension: Prescribing information. FDA.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.

3. U.S. Food and Drug Administration. (2011). ONFI approval letter and regulatory review materials. FDA.

4. U.S. Food and Drug Administration. (n.d.). Approved drug products database. FDA.

5. U.S. Food and Drug Administration. (2017). Abbreviated new drug application submissions: Refuse-to-receive standards. FDA.