List of Excipients in Branded Drug DILANTIN INFATABS

Generic Drugs Containing DILANTIN INFATABS

Company	Ingredient	NDC	Excipient
Parke-Davis Div of Pfizer Inc	phenytoin	0071-0007	D&C YELLOW NO. 10 ALUMINUM LAKE
Parke-Davis Div of Pfizer Inc	phenytoin	0071-0007	FD&C YELLOW NO. 6
Parke-Davis Div of Pfizer Inc	phenytoin	0071-0007	MAGNESIUM STEARATE
Parke-Davis Div of Pfizer Inc	phenytoin	0071-0007	SACCHARIN SODIUM

What are the Most Frequently-Used Excipients in DILANTIN INFATABS?

# Of NDCs	Excipient
1	D&C YELLOW NO. 10 ALUMINUM LAKE
1	FD&C YELLOW NO. 6
1	MAGNESIUM STEARATE
1	SACCHARIN SODIUM

DILANTIN INFATABS Excipient Strategy and Commercial Opportunities

Last updated: August 23, 2026

Dilantin Infatabs is a 50 mg phenytoin chewable tablet historically marketed by Parke-Davis, now associated with Pfizer. Its commercial value is concentrated in pediatric and swallowing-challenged patients, dose titration, and the clinical familiarity of the Dilantin brand. The strongest opportunity is not a new excipient patent around phenytoin itself. It is a differentiated, bioequivalent chewable dosage form that improves palatability, dose flexibility, supply reliability, or administration without disrupting phenytoin exposure.

What is Dilantin Infatabs and who uses it?

Dilantin Infatabs contains phenytoin, an antiseizure medicine used for tonic-clonic and focal seizures. Each chewable tablet contains 50 mg of phenytoin. The product is intended for oral administration and can be useful when patients cannot swallow conventional capsules or tablets.

Attribute	Dilantin Infatabs profile
Active ingredient	Phenytoin
Strength	50 mg per chewable tablet
Dosage form	Chewable tablet
Therapeutic category	Antiseizure medicine
Reference product	Dilantin Infatabs
Primary users	Pediatric patients, patients with dysphagia, patients requiring dose titration
Key clinical constraint	Narrow therapeutic index and nonlinear pharmacokinetics
Commercial positioning	Dose flexibility and administration convenience
Main substitution risks	Phenytoin suspension, capsules, extended-release products, compounded formulations, and generic solid oral products

Phenytoin presents a difficult formulation environment. Small changes in absorption, dissolution, particle size, excipient composition, or administration conditions can affect plasma exposure. The drug also follows capacity-limited metabolism, so modest concentration changes can produce disproportionate changes in serum levels.

What excipients are used in Dilantin Infatabs?

Public labeling identifies conventional tablet excipients associated with the product, including sucrose, talc, acacia, magnesium stearate, flavoring, and coloring components. Product presentations and labeling should be checked against the current DailyMed entry and the applicable FDA prescribing information before use in a regulatory or litigation analysis.[1]

Excipient function	Reported or historically associated material	Formulation role
Diluent and sweetener	Sucrose	Provides tablet bulk and sweetness
Binder	Acacia	Supports granulation and mechanical strength
Glidant or anti-adherent	Talc	Improves powder flow and processing
Lubricant	Magnesium stearate	Reduces sticking and ejection force
Flavor system	Peppermint or comparable flavoring	Reduces phenytoin bitterness
Colorant	Product-specific color system	Supports product identification and patient acceptability

The excipient architecture is commercially important because phenytoin is bitter, the product must withstand chewing, and the dosage form must deliver reproducible drug release. A modern replacement should not be evaluated only for hardness and disintegration. Taste, mouthfeel, chewability, dose uniformity, dissolution, impurity formation, and serum exposure are all relevant.

What excipients create the greatest development constraints?

Sucrose can support palatability but creates risks for patients with dietary restrictions, dental concerns, or diabetes-related formulation preferences. Acacia is a traditional binder but can introduce variability in granulation behavior and may be less attractive for a modern excipient platform than a well-characterized synthetic or semi-synthetic binder.

Talc and magnesium stearate are familiar manufacturing aids, but excessive lubrication can slow wetting and dissolution. This issue is relevant for phenytoin because dissolution performance can affect bioavailability. Flavoring systems can also alter wetting, tablet porosity, and patient acceptance.

A replacement product should preserve the functional advantages of the legacy system while reducing avoidable liabilities:

• lower sugar load;
• improved bitterness suppression;
• lower tablet mass;
• stronger resistance to friability;
• consistent chewability across storage conditions;
• compatibility with pediatric use;
• reduced dependence on animal-derived or variable natural materials where relevant;
• improved control of dissolution and content uniformity.

How does phenytoin pharmacokinetics affect excipient strategy?

Phenytoin has nonlinear, dose-dependent pharmacokinetics. It is highly protein-bound and has a narrow therapeutic range. The relationship between dose and serum concentration is not proportional once metabolic pathways approach saturation.[2]

This makes excipient changes more consequential than they would be for a wide-therapeutic-index product. A new chewable formulation should generate comparative data covering:

1. dissolution across physiologically relevant pH conditions;
2. fed and fasted administration;
3. tablet chewing versus swallowing whole;
4. administration with water, milk, soft food, or enteral nutrition;
5. content uniformity at the 50 mg unit level;
6. particle-size distribution and polymorphic form;
7. exposure to humidity and temperature;
8. serum phenytoin concentration profiles where required by the FDA pathway.

A formulation that improves taste but changes absorption may face physician resistance even if it satisfies ordinary pharmaceutical quality specifications. The commercial message must therefore emphasize interchangeability and therapeutic consistency, not only convenience.

What commercial opportunities exist for a new Dilantin Infatabs-type product?

1. Sugar-reduced or sugar-free chewable tablets

A sugar-reduced platform is the clearest excipient-led opportunity. It could replace sucrose with polyols, directly compressible carbohydrates, or other sweetening and bulking systems. The key issues are gastrointestinal tolerance, cooling sensation, hygroscopicity, tablet strength, and taste masking.

Polyols can improve dental positioning but may cause laxation at sufficiently high intake. High-intensity sweeteners can reduce tablet mass but often leave bitterness or aftertaste. A blended system is more likely to achieve acceptable palatability than a single sweetener.

2. Superior taste masking

Phenytoin has a strong bitter taste. A modern formulation could use:

• polymeric taste-masking coatings;
• ion-exchange resins;
• lipid barriers;
• pH-responsive coatings;
• microencapsulated phenytoin particles;
• flavor systems designed for rapid bitterness suppression.

The regulatory challenge is that taste-masking technologies can change dissolution. Any coated or complexed particle must demonstrate rapid and reproducible drug release after swallowing and sufficient release after chewing.

A defensible commercial position would combine taste performance with a measurable dissolution profile and patient-preference data. Taste claims alone are easier to copy than a formulation that links particle engineering, excipient selection, and release control.

3. Smaller, easier-to-chew tablets

A lower-mass 50 mg tablet could improve pediatric administration and reduce choking concerns. This may require higher drug loading, porous granulation, orally disintegrating technology, or a multiparticulate design.

The main risk is mechanical fragility. A tablet that is easy to chew may be too soft for packaging, transport, and automated dispensing. Packaging development should be integrated with the excipient program rather than treated as a later activity.

4. Flexible-dose platforms

A scored 50 mg chewable tablet may support 25 mg increments, but splitting performance must be demonstrated. A multiparticulate product could provide more precise dose adjustment, but it would create additional regulatory and manufacturing complexity.

Potential products include:

Product concept	Commercial benefit	Principal technical risk
50 mg sugar-reduced chewable	Broadest reformulation opportunity	Sweetener, taste, and dissolution balance
25 mg pediatric chewable	More precise titration	Higher manufacturing and packaging cost
Taste-masked mini-tablet	Pediatric and dysphagia positioning	Chewing-related release variability
Sprinkleable multiparticulates	Administration with soft food	Dose uniformity and food interaction
Orodispersible tablet	Administration without water	Rapid bitterness exposure and friability
Unit-dose sachet or blister	Institutional and adherence use	Packaging cost and moisture sensitivity

What patent opportunities exist around Dilantin Infatabs excipients?

The original phenytoin compound and legacy chewable formulation are unlikely to provide a meaningful new-product exclusivity position by themselves. The strongest patent opportunity would come from a narrow, technically demonstrated formulation combination.

Potential claim categories include:

• phenytoin particles with a specified particle-size distribution;
• phenytoin combined with a defined taste-masking polymer;
• a specific ratio of binder, sweetener, lubricant, and disintegrant;
• a chewable tablet meeting defined dissolution and mechanical parameters;
• a sugar-free dosage form with specified palatability and exposure characteristics;
• a multiparticulate system administered with soft food;
• a manufacturing process that controls segregation and content uniformity;
• packaging that stabilizes the dosage form under defined humidity conditions.

A patent application should avoid relying only on a list of familiar excipients. A simple substitution of sucrose with another sweetener may face obviousness challenges unless the formulation produces an unexpected result, such as simultaneous improvement in taste, dissolution, tablet strength, and bioequivalence.

What is the likely patent strength of a new excipient formulation?

Claim type	Expected strength	Commercial assessment
Broad phenytoin chewable composition	Low	Likely vulnerable to prior art
Sugar-free phenytoin tablet	Low to moderate	Stronger if linked to unexpected performance
Specific taste-masking system	Moderate	Depends on prior art and measured sensory results
Defined particle-engineering platform	Moderate to strong	Better if it controls exposure and taste
Manufacturing process with critical parameters	Moderate	Useful against process-copying competitors
Device or packaging claim	Moderate	Narrow but potentially enforceable
Method-of-use claim for pediatric administration	Low to moderate	Clinical and obviousness issues may limit value

Patent term should be calculated from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and prosecution history. A new formulation filed in the current period would not provide protection against established generic phenytoin products until the patent issues and would face the usual written-description, enablement, obviousness, and anticipation risks.

What is the FDA regulatory status of Dilantin Infatabs?

Dilantin Infatabs is an FDA-approved phenytoin product associated with an approved new drug application. The applicable FDA labeling and Drugs@FDA records control the product’s current approval, marketing status, labeling, and listed inactive ingredients.[1,3]

For a new product, the regulatory pathway depends on the product’s relationship to the reference drug:

• An ANDA may be available if the proposed product can meet applicable pharmaceutical equivalence and bioequivalence requirements.
• A 505(b)(2) application may be appropriate if the product relies partly on published literature, FDA findings, or a modified dosage form that cannot fit a conventional ANDA pathway.
• A fully independent NDA would be less commercially attractive unless the formulation offers a clinically meaningful advantage or a different route, indication, or delivery system.

A new excipient or substantially changed excipient system can increase the amount of chemistry, manufacturing, controls, safety, and bioequivalence work. Excipients with established oral use are preferable, but prior use in other drugs does not eliminate the need to justify the specific formulation.

What Orange Book and Paragraph IV issues apply?

Orange Book analysis should distinguish between the reference listed drug, currently listed patents, product-specific labeling, and any generic approvals. The relevant questions are:

1. Is Dilantin Infatabs currently listed as a reference listed drug for an approved ANDA?
2. Are any formulation, method-of-use, or other patents listed for the product?
3. Does an ANDA applicant need to submit a Paragraph IV certification?
4. Are any listed patents expired, delisted, or subject to litigation?
5. Is the proposed generic product therapeutically equivalent to the same dosage form?

A Paragraph IV challenge could target listed patents covering a chewable formulation, method of administration, or manufacturing process. If no relevant patents are listed, the primary barriers would be formulation development, bioequivalence, manufacturing scale-up, and market economics rather than patent litigation.

For a differentiated 505(b)(2) product, patent protection would be more important because the developer would need to create a commercial return despite competition from low-cost phenytoin products. Regulatory exclusivity may be available in certain circumstances, but it would depend on the approval basis and the nature of the innovation. FDA approval alone would not create broad market exclusivity for a routine excipient substitution.

When does Dilantin Infatabs lose exclusivity?

The core phenytoin molecule is long off patent. The commercial protection for Dilantin Infatabs therefore depends on brand recognition, manufacturing history, supply reliability, regulatory status, and any remaining product-specific patents rather than basic active-ingredient exclusivity.

Protection type	Dilantin Infatabs relevance
Active-ingredient patent	Expired
Original formulation patent	Expected to be expired or commercially immaterial
New formulation patent	Available only for a newly developed and patentable product
Pediatric exclusivity	Must be confirmed from FDA records for the relevant approval
Orphan exclusivity	Not generally associated with standard phenytoin seizure use
Regulatory exclusivity for a reformulation	Depends on the approval pathway and FDA findings
Brand protection	Continues through trademark rights and market recognition

No reliable commercial forecast should assume that a legacy brand has meaningful patent exclusivity without a current Orange Book and patent-family review.

What generic entry risks exist for a Dilantin Infatabs-type product?

Generic entry risk is high for a conventional 50 mg chewable tablet if the product can be reproduced using standard excipients and achieves acceptable bioequivalence. A generic manufacturer could compete on price, wholesaler access, and pharmacy substitution.

Risk is lower for a product with a technically difficult formulation, but only if the formulation is protected and the commercial market rewards the difference. The most defensible barriers are:

• difficult-to-reproduce taste-masking particles;
• a validated particle-size and dissolution-control process;
• specialized packaging;
• a proprietary manufacturing platform;
• clinically supported administration with soft food;
• a formulation patent with strong experimental support.

A brand strategy based only on flavor or color is weak. A strategy based on pediatric usability, consistent exposure, and supply reliability is stronger but requires clinical and commercial investment.

How does Dilantin Infatabs compare with other phenytoin dosage forms?

Dosage form	Strengths	Weaknesses	Excipient opportunity
Infatabs chewable	Dose flexibility and administration convenience	Taste and formulation sensitivity	Sugar reduction, taste masking, smaller tablet
Immediate-release suspension	Flexible dosing and pediatric use	Shake dependence, sedimentation, dosing errors	Improved suspension stability and taste
Extended-release capsules	Established adult use	Less suitable for dysphagia and rapid titration	Capsule fill uniformity and alternative delivery
Conventional tablets	Low cost and manufacturing simplicity	Swallowing burden	Scored, smaller, or dispersible versions
Compounded liquid	Custom dosing	Variable quality and availability	Ready-to-use standardized liquid
Multiparticulates	Flexible administration	More complex manufacturing	Soft-food administration and dose precision

The principal competitive product is not another chewable tablet. It is the broader set of phenytoin administration options. A new Infatabs-type product must therefore show why it is better than suspension, capsules, and compounded liquid for the target population.

Which commercial opportunities are most attractive?

The strongest near-term opportunities are:

1. A sugar-reduced, strongly taste-masked 50 mg chewable tablet using established excipients.
2. A 25 mg pediatric unit that supports precise titration.
3. A sprinkleable multiparticulate formulation for patients unable to swallow tablets.
4. A licensed or co-developed product for markets where pediatric phenytoin supply is unreliable.
5. A branded-generic strategy based on consistent manufacturing, patient acceptability, and hospital procurement.

The market is likely price-sensitive because phenytoin is a mature molecule. Premium pricing requires a clear operational benefit, such as reduced administration errors, better adherence, improved pediatric acceptance, or lower dependence on compounded products.

What licensing and partnership opportunities exist?

Potential partners include:

• generic manufacturers with ANDA infrastructure;
• specialty pharmaceutical companies focused on pediatric medicines;
• excipient suppliers with taste-masking or particle-engineering platforms;
• contract development and manufacturing organizations;
• hospital-oriented suppliers;
• regional distributors in markets with limited pediatric dosage-form availability.

A licensing deal should separate rights to the active formulation, taste-masking technology, manufacturing process, trademarks, and territory. The most valuable package would include a formulation patent family, scalable manufacturing process, stability data, sensory data, and a defined regulatory pathway.

Key Takeaways

• Dilantin Infatabs is a 50 mg phenytoin chewable tablet with commercial relevance in pediatric and dysphagia populations.
• The formulation challenge is the interaction among bitterness, chewability, dissolution, and phenytoin exposure.
• Sucrose, acacia, talc, magnesium stearate, flavoring, and color systems are central to the legacy excipient design, subject to confirmation against current FDA labeling.
• The best reformulation opportunity is a sugar-reduced or sugar-free chewable product with strong taste masking and preserved bioavailability.
• Broad excipient patents are likely weak. Narrow claims supported by particle engineering, dissolution control, sensory data, and manufacturing parameters are more defensible.
• The active-ingredient patent estate is expired, so commercial protection must come from formulation patents, regulatory strategy, brand positioning, manufacturing capability, and supply reliability.
• Generic entry risk is high for a conventional chewable tablet and lower for a technically differentiated product with enforceable claims.
• A 505(b)(2) strategy may be more commercially suitable than a routine generic pathway where the product offers a materially improved dosage form.

FAQs

Can sucrose be removed from Dilantin Infatabs without changing bioavailability?

Yes, but the replacement system must be evaluated for dissolution, tablet porosity, wetting, taste, and comparative exposure. Sucrose removal is not a purely sensory change.

Is a phenytoin chewable tablet eligible for an ANDA?

Potentially, if the proposed product meets applicable pharmaceutical-equivalence and bioequivalence requirements. A materially different delivery system or clinical claim may require a 505(b)(2) application.

Are phenytoin chewable tablets difficult to patent?

A routine excipient substitution is difficult to protect. A formulation that combines taste masking, controlled dissolution, dose uniformity, and demonstrated pharmacokinetic consistency has a stronger patent position.

What excipient is best for masking phenytoin bitterness?

No single excipient is universally best. Polymer coatings, ion-exchange systems, lipid barriers, and microencapsulation should be screened against dissolution, chewability, stability, and sensory performance.

Could a new Dilantin Infatabs formulation support pediatric exclusivity?

Possibly, but pediatric exclusivity depends on an FDA-requested and completed pediatric study program and the resulting regulatory determination. It cannot be assumed from a pediatric dosage form alone.

References

1. U.S. National Library of Medicine. (n.d.). DailyMed: Dilantin Infatabs phenytoin tablet, chewable labeling.
2. U.S. Food and Drug Administration. (2022). Dilantin prescribing information. Pfizer.
3. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs.
4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations.
5. U.S. Food and Drug Administration. (2016). Inactive Ingredient Database.
6. U.S. Food and Drug Administration. (2013). Guidance for industry: Bioequivalence studies with pharmacokinetic endpoints for drugs submitted under an ANDA.
7. U.S. Food and Drug Administration. (2023). Regulatory classification of pharmaceutical co-crystals and related dosage-form guidance.