List of Excipients in Branded Drug VALPROIC ACID

Generic Drugs Containing VALPROIC ACID

Company	Ingredient	NDC	Excipient
Xttrium Laboratories Inc	valproic acid	0116-4021	ALCOHOL
Xttrium Laboratories Inc	valproic acid	0116-4021	CHERRY
Xttrium Laboratories Inc	valproic acid	0116-4021	CORN SYRUP
Xttrium Laboratories Inc	valproic acid	0116-4021	FD&C RED NO. 40
Xttrium Laboratories Inc	valproic acid	0116-4021	GLYCERIN

What are the Most Frequently-Used Excipients in VALPROIC ACID?

# Of NDCs	Excipient
8	ALCOHOL
5	ANHYDROUS CITRIC ACID
1	CHERRY
1	CITRIC ACID MONOHYDRATE
14	CORN OIL

Valproic Acid Excipient Strategy and Commercial Opportunities

Last updated: September 17, 2026

Valproic acid is an established, off-patent antiepileptic and mood-stabilizing active ingredient with substantial formulation demand. The strongest commercial opportunities are in taste masking, pediatric delivery, modified-release systems, gastrointestinal tolerability, lower-pill-burden products, and differentiated generic or specialty formulations. Active-ingredient patent exclusivity is largely exhausted, so competitive protection must come from formulation performance, manufacturing know-how, regulatory differentiation, and device or packaging integration.

What pharmaceutical products contain valproic acid?

Valproate products use three principal active forms:

Active form	Common product type	Formulation relevance
Valproic acid	Oral capsules, oral solution, injectable products	Strong taste and odor burden; liquid handling and stability are central
Sodium valproate	Tablets, injection, combination products	Higher aqueous solubility; salt selection affects dose, hygroscopicity, and processing
Divalproex sodium	Delayed-release and extended-release tablets	Composite molecule that dissociates into valproate; coating and release control are critical

The U.S. Food and Drug Administration has approved valproate products for epilepsy and bipolar disorder, and valproic acid is also used for migraine prophylaxis in certain markets and clinical settings. Divalproex sodium products include Depakote delayed-release tablets and Depakote ER extended-release tablets, originally commercialized by Abbott Laboratories and now associated with AbbVie’s legacy pharmaceutical portfolio.[1]

Valproate products carry significant safety restrictions, including teratogenicity and risks involving hepatotoxicity, pancreatitis, thrombocytopenia, hyperammonemia, and fetal neurodevelopment. Excipient selection cannot create a regulatory advantage that offsets active-ingredient safety limitations. It can, however, improve adherence, dosing convenience, swallowability, and pharmacokinetic control.

What excipient problems are most important in valproic acid formulations?

The main formulation problems are unpleasant taste and odor, liquid dose variability, gastrointestinal intolerance, hygroscopicity of valproate salts, dose volume, and the need to control release without compromising bioavailability.

Taste and odor

Valproic acid has a strong, unpleasant odor and taste. This creates a particular problem in pediatric, geriatric, and neurologically impaired populations. Conventional sweeteners alone are unlikely to provide adequate sensory masking because the active ingredient has both taste and odor components.

Relevant excipient approaches include:

• Polymer film coating for tablets, capsules, and multiparticulates
• Ion-exchange resins
• Lipid or wax matrices
• Cyclodextrin complexation
• Microencapsulation
• pH-responsive polymers
• Flavor systems used with oral liquids
• Viscosity modifiers that reduce rapid contact with taste receptors

Ion-exchange resins and microencapsulation are attractive for pediatric suspensions because they can reduce immediate exposure of valproate to the oral cavity while allowing release in the gastrointestinal tract. The main development risk is ensuring that complexation does not reduce dose uniformity or delay absorption beyond the intended product profile.

Oral-liquid palatability

Oral solutions and syrups require a coordinated excipient system rather than a single flavoring agent. The development package may include:

• Sweeteners such as sucrose, sorbitol, or high-intensity sweeteners
• Flavor combinations designed to suppress bitterness and chemical odor
• Buffers to maintain pH
• Preservatives where required
• Suspending or viscosity-modifying agents for suspension products
• Chelating agents and antioxidants where chemical stability requires them
• Low-sugar or sugar-free vehicles for diabetes and pediatric use

A sugar-free, alcohol-free, low-volume formulation could have commercial value in pediatric and chronic-care settings. The excipient system must remain compatible with high-dose administration, because valproate doses can be substantial relative to typical oral-liquid volumes.

Modified release

Extended-release and delayed-release valproate products rely on coating polymers, matrix formers, or multiparticulate technologies. Common excipient classes include:

• Methacrylate copolymers
• Cellulose derivatives
• Hypromellose
• Ethylcellulose
• Polyethylene oxide
• Polyvinyl acetate-based matrix systems
• Plasticizers such as triethyl citrate or polyethylene glycol
• Anti-tacking agents such as talc or colloidal silicon dioxide

A modified-release product must control dose dumping, food effects, tablet integrity, and interpatient pharmacokinetic variability. These risks are material because valproate has concentration-dependent clinical monitoring requirements and a narrow margin between inadequate seizure control and toxicity for some patients.

What formulation strategies offer the strongest commercial opportunity?

The best opportunities are products that solve a practical administration problem without materially increasing regulatory complexity.

Pediatric sprinkle and multiparticulate formulations

A sprinkle formulation can allow patients to administer valproate over soft food without swallowing a conventional tablet or capsule. A commercially viable product would need:

• Taste-masked drug-containing particles
• Controlled release or enteric protection, where clinically required
• Minimal grittiness
• Stability in contact with food
• Clear instructions for immediate administration
• Dose uniformity across the delivered portion

Multiparticulates can support flexible dosing and may reduce the need for liquid products. They also create formulation and process IP around particle size, coating thickness, polymer ratios, and manufacturing conditions.

Low-volume oral solutions

High-dose valproate therapy can create a meaningful burden when the concentration is low. A concentrated oral solution can reduce dose volume, but it increases the importance of dosing-device accuracy and local tolerability. Commercial differentiation could come from:

• Higher concentration with acceptable viscosity
• Oral syringe compatibility
• Odor reduction
• Child-resistant packaging
• Unit-dose packaging for institutional use
• Preservative-free or reduced-preservative versions

A higher concentration is not automatically superior. It can increase dosing errors if the product is confused with lower-strength liquids or if caregivers use household spoons.

Extended-release tablets

Extended-release products reduce dosing frequency and may improve adherence. Excipient opportunities include robust matrix systems, film coatings that limit tablet erosion, and technologies that reduce sensitivity to food intake.

The commercial value is greatest where the formulation can demonstrate:

• Once-daily dosing
• Consistent exposure over 24 hours
• Lower peak-to-trough fluctuation
• Comparable clinical control with fewer daily administrations
• Reduced gastrointestinal complaints
• Simple switching instructions from immediate-release or delayed-release products

A generic extended-release product faces greater development and bioequivalence risk than an immediate-release capsule or solution. The value of excipient innovation rises with the complexity of the release profile.

Gastrointestinal-tolerability systems

Valproate can cause nausea, vomiting, abdominal pain, dyspepsia, and diarrhea. Enteric coatings or delayed-release matrices may reduce upper-gastrointestinal exposure, but they can also introduce food effects and variable absorption. A useful excipient platform would target release location and rate while maintaining reliable systemic exposure.

Potential commercial products include:

• Enteric-coated capsules
• Delayed-release multiparticulates
• Lower-peak extended-release products
• Lipid-based systems that improve dispersion
• Formulations designed for administration with controlled meal conditions

Clinical claims would require evidence. Excipient-driven improvements in tolerability are commercially valuable only if supported by comparative clinical or pharmacokinetic data.

How does valproic acid compare with sodium valproate and divalproex sodium?

Attribute	Valproic acid	Sodium valproate	Divalproex sodium
Physical form	Free acid; oily liquid or encapsulated material	Ionic salt; generally more water soluble	Coordination compound of valproic acid and sodium valproate
Taste and odor	High masking burden	Taste remains relevant, especially in liquids	Coating and release control are more important
Oral-liquid potential	Feasible but sensory challenge is high	Strong candidate because of solubility	Less commonly used as a simple solution
Modified-release opportunity	Requires conversion or matrix control	Salt properties affect processing	Established delayed- and extended-release platform
Manufacturing risk	Fill accuracy, odor control, capsule compatibility	Hygroscopicity and powder handling	Content uniformity, coating, dissolution, conversion
Differentiation potential	Taste masking and liquid delivery	Solubility and dose flexibility	Release profile and dosing convenience

The choice of active form affects excipient demand. Sodium valproate is generally easier to formulate into aqueous systems, while valproic acid creates a stronger need for odor management and encapsulation. Divalproex sodium offers more room for modified-release differentiation but requires more demanding dissolution and bioequivalence control.

What patents protect valproic acid formulations?

The basic valproic acid active ingredient is no longer protected by meaningful composition-of-matter exclusivity in the United States. Commercial protection has historically centered on:

• Divalproex sodium composition and manufacturing
• Delayed-release tablets
• Extended-release tablets
• Specific dissolution profiles
• Pharmaceutical compositions
• Methods of treating epilepsy, bipolar disorder, or migraine
• Salt and conversion processes
• Coated multiparticulates
• Formulation and manufacturing controls

The historic Depakote and Depakote ER patent estates generated extensive generic litigation, but the major market barriers have expired or lost practical relevance. Current patent risk should be assessed product by product in the FDA Orange Book, because listed patents can differ by dosage form, strength, and indication.[2]

Orange Book status

The Orange Book is the controlling public source for currently listed patents and regulatory exclusivities for approved small-molecule products. It should be reviewed for:

• Depakene capsules and oral solution
• Depakote delayed-release tablets
• Depakote ER extended-release tablets
• Valproate sodium injection
• Generic products with their own listed formulation or method-of-use patents

A product may have no meaningful remaining exclusivity even if historical patents appear in litigation records. Conversely, a narrow method-of-use patent can affect a specific indication without blocking all generic sales.

Paragraph IV challenges

Paragraph IV certifications are most relevant to any remaining listed patents covering:

• Extended-release valproate products
• Delayed-release formulations
• Specific tablet strengths
• Method-of-use claims
• New delivery systems

A generic applicant that certifies a listed patent as invalid, unenforceable, or not infringed can trigger Hatch-Waxman litigation. The 30-month stay, 180-day first-filer exclusivity, and possible settlement restrictions depend on the particular filing and patent status.[3]

For legacy valproate products, the principal commercial risk is usually not the existence of a historical Paragraph IV case. It is whether a current listed patent can delay approval or materially restrict the launch of a differentiated formulation.

When does valproic acid lose exclusivity?

Valproic acid and the principal branded valproate products have already lost core market exclusivity. Depakene and Depakote products have faced generic competition for many years, and the market is dominated by low-cost generic alternatives.

Exclusivity category	Current commercial relevance
New chemical entity exclusivity	Expired
Basic active-ingredient patents	Expired or commercially exhausted
Historic Depakote formulation patents	Largely expired; product-specific review remains necessary
Method-of-use patents	May remain relevant for narrow indications if listed and enforceable
Pediatric exclusivity	Historic relevance only
New formulation patents	Potentially available for newly developed delivery systems
Orphan exclusivity	Not generally the principal protection for conventional valproate products

The realistic route to market protection is a new formulation, device, delivery system, or narrowly defined method of use. A new excipient combination alone may not support strong patent claims unless it produces a reproducible technical effect, such as a defined dissolution profile, improved stability, reduced odor, improved taste, or reduced pharmacokinetic variability.

What regulatory pathway applies to new valproic acid products?

For a conventional generic, the likely pathway is an Abbreviated New Drug Application showing pharmaceutical equivalence and bioequivalence to a reference-listed drug. Immediate-release products are generally less technically demanding than extended-release, delayed-release, or complex multiparticulate products.

A 505(b)(2) application may be more suitable when the sponsor develops:

• A new dosage form
• A new route of administration
• A novel concentration
• A clinically differentiated release profile
• A new combination involving valproate
• A formulation with limited ability to rely on a conventional generic pathway

FDA approval also requires careful control of labeling, medication guides, reproductive-risk information, pediatric dosing, and drug-interaction warnings.[1][4]

For complex generic products, the excipient strategy must be designed around the bioequivalence program from the beginning. Changes in polymer grade, coating weight, particle size, compression force, or lubricant concentration can alter dissolution and systemic exposure.

What manufacturing and intellectual-property barriers matter most?

The most defensible barriers are process-based rather than ingredient-based.

Manufacturing barriers

• Uniform filling of low-viscosity valproic acid
• Odor containment during production
• Control of hygroscopic sodium valproate
• Reproducible coating of multiparticulates
• Particle-size control
• Prevention of dose dumping
• Consistent dissolution across commercial scale
• Packaging that limits moisture and odor migration
• Compatibility with high-speed tablet or capsule equipment

A formulation may be difficult to copy even without a broad patent if it depends on narrow process windows, specialized coating equipment, proprietary analytical methods, or difficult-to-source excipient grades.

Patentable formulation elements

Potential claim categories include:

• Defined polymer ratios
• Specific coating weight gain
• Multi-layer particle architecture
• Particle-size distributions
• Taste-masking complexes
• Controlled-release matrices
• Excipient combinations that reduce odor
• Stability-improving packaging
• Manufacturing parameters linked to dissolution performance
• Dosing devices calibrated to concentrated solutions

Patent strength depends on whether the claims cover a commercially necessary feature and whether competitors can design around them. A narrow claim to one flavor system is usually weaker than a claim tied to a measurable dissolution, stability, or pharmacokinetic result.

Which companies and products compete in the valproate market?

Competition includes originator-associated products, generic pharmaceutical manufacturers, and specialty suppliers of modified-release technology.

Competitive segment	Typical competitors
Immediate-release capsules and solutions	Teva, Viatris, Hikma, Zydus, and other approved generic manufacturers
Delayed-release tablets	Generic manufacturers with bioequivalent divalproex products
Extended-release tablets	Manufacturers with complex generic capabilities
Injectable sodium valproate	Hospital-focused generic and specialty injectable suppliers
Excipient and delivery technology	BASF, Evonik, Lubrizol, Colorcon, Ashland, Roquette, and specialty taste-masking or coating suppliers

The competitive landscape is fragmented by dosage form. A company capable of making a conventional capsule may not have the capability to develop a robust extended-release tablet or pediatric multiparticulate.

What licensing deals and commercial models are available?

The most practical licensing opportunities involve technology platforms rather than valproic acid rights.

Potential models include:

1. Licensing a taste-masking platform for pediatric valproate.
2. Co-developing an extended-release or sprinkle product with a generic manufacturer.
3. Supplying a proprietary excipient blend under a quality and supply agreement.
4. Licensing a manufacturing process with equipment and analytical transfer.
5. Partnering with a specialty pharmaceutical company for a 505(b)(2) product.
6. Developing a hospital injectable formulation with improved stability or packaging.
7. Combining a formulation license with regional commercialization rights.

A supplier should seek protection through multiple layers: composition claims, process claims, analytical methods, product-by-process limitations where appropriate, and confidential manufacturing know-how. Because the active ingredient is inexpensive, excipient pricing alone is unlikely to support a large commercial opportunity unless the excipient is tied to a differentiated finished product.

What is the revenue exposure and generic launch risk?

Valproate is a mature, high-volume, low-price market. Revenue exposure is concentrated in differentiated dosage forms rather than standard immediate-release products.

Product opportunity	Revenue potential	Development risk	Commercial attractiveness
Standard capsule	Low	Low	Limited
Conventional oral solution	Low to moderate	Low to moderate	Moderate where supply is constrained
Sugar-free or low-volume solution	Moderate	Moderate	Attractive in pediatric and chronic-care channels
Sprinkle multiparticulate	Moderate to high	High	Strong differentiation potential
Extended-release tablet	Moderate to high	High	Attractive but bioequivalence-intensive
Hospital injection	Moderate	Moderate to high	Driven by supply reliability and contracting
Novel delivery system	High if clinically differentiated	High	Dependent on reimbursement and evidence

Generic launch risk is greatest for products requiring complex bioequivalence testing or facing narrow market size. It is lower for simple capsules and solutions, although price erosion can be severe. A formulation company should avoid competing solely on unit price against established generic manufacturers.

How strong is the patent estate for a new valproic acid excipient formulation?

A new valproic acid formulation can have a moderate patent position if it combines:

• A clinically relevant administration benefit
• A non-obvious excipient architecture
• Quantifiable dissolution or pharmacokinetic performance
• Manufacturing complexity
• A clear regulatory pathway
• Limited design-around options

The estate is weak when the product relies on routine flavoring, standard tablet coatings, or commonly used polymers without a defined technical result. The best protection usually comes from a coordinated package of formulation patents, process patents, trade secrets, regulatory exclusivity, and commercial scale-up capability.

Key Takeaways

• Valproic acid is an off-patent active ingredient with extensive generic competition.
• The strongest excipient opportunities are taste masking, odor reduction, pediatric sprinkle systems, concentrated oral liquids, and modified-release tablets.
• Sodium valproate is more suitable for aqueous formulations, while valproic acid creates greater sensory and handling challenges.
• Divalproex sodium offers the greatest formulation complexity and potential for differentiated release profiles.
• Current patent analysis must rely on dosage-form-specific Orange Book listings rather than historical Depakote litigation alone.
• A new product is more likely to succeed through formulation performance, manufacturing know-how, and regulatory differentiation than through active-ingredient exclusivity.
• Extended-release and multiparticulate products offer greater commercial upside but carry higher bioequivalence and scale-up risk.
• Licensing opportunities are strongest for excipient platforms, coating technologies, taste-masking systems, and specialty pharmaceutical partnerships.

FAQs

Can valproic acid be formulated as a pediatric liquid?

Yes. Oral liquids are commercially established, but taste, odor, dose volume, preservative selection, and dosing-device accuracy are central development issues. A concentrated, sugar-free, taste-masked liquid could provide meaningful differentiation.

Which excipients are best for masking valproic acid taste?

Polymer coatings, ion-exchange resins, lipid matrices, cyclodextrins, and microencapsulation systems are more promising than flavoring alone. Selection depends on whether the product is an immediate-release liquid, sprinkle, capsule, or modified-release tablet.

Is divalproex sodium easier to patent than valproic acid?

Divalproex sodium offers more formulation complexity because delayed-release and extended-release performance can be linked to coatings, matrices, particle architecture, and dissolution profiles. Patentability still depends on technical novelty and non-obviousness.

Does a new valproic acid excipient combination qualify for market exclusivity?

Not automatically. The formulation must satisfy patentability requirements and the finished product must qualify under the applicable FDA pathway. A new excipient combination may support patent protection, but it does not by itself create regulatory exclusivity.

What is the most commercially attractive valproate formulation?

A pediatric-friendly sprinkle or multiparticulate product with strong taste masking and flexible dosing has a compelling differentiation profile. An extended-release product can offer greater revenue potential, but it requires more expensive development and more demanding bioequivalence evidence.

References

1. U.S. Food and Drug Administration. (2023). Depakene and valproic acid prescribing information. FDA Drugs@FDA.

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

3. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355.

4. U.S. Food and Drug Administration. (2024). Guidance for industry: ANDAs for certain highly purified synthetic peptides. FDA.

5. DailyMed. (2024). Valproic acid, divalproex sodium, and valproate sodium product labeling. National Library of Medicine.