List of Excipients in Branded Drug GRIS-PEG

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	MAGNESIUM STEARATE
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	METHYLPARABEN
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	POLYETHYLENE GLYCOL 3350
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	POLYETHYLENE GLYCOL 8000
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	POLYVINYL ALCOHOL
Pedinol Pharmacal Inc	GRIS-PEG	griseofulvin	0884-0773	SODIUM LAURYL SULFATE

GRIS-PEG Excipient Strategy and Commercial Opportunities

Last updated: September 26, 2026

GRIS-PEG is the U.S. branded formulation of griseofulvin ultramicrosize, an oral antifungal used for dermatophyte infections. Its commercial value is driven by formulation performance rather than new-molecule exclusivity. The strongest opportunities are generic substitution, pediatric and geriatric dosage forms, food-independent absorption, and differentiated tablets or oral liquids.

What is GRIS-PEG and how does its formulation work?

GRIS-PEG contains griseofulvin in an ultramicrosize particle form. The formulation is designed to improve dissolution and oral absorption compared with conventional griseofulvin particles.[1]

Attribute	GRIS-PEG profile
Active ingredient	Griseofulvin ultramicrosize
Drug class	Oral antifungal
Primary use	Dermatophyte infections, including tinea and onychomycosis
U.S. dosage strengths	125 mg and 250 mg tablets
Administration	Oral
Formulation issue	Poor aqueous solubility and dissolution-limited absorption
Absorption sensitivity	Food, particularly dietary fat, can affect exposure
Regulatory pathway for competitors	Abbreviated New Drug Application, subject to product-specific requirements
Biologic status	Not applicable
Biosimilar exposure	None

Griseofulvin is practically insoluble in water. The ultramicrosize approach increases surface area and supports faster dissolution. The formulation therefore depends on both the particle-size distribution of the active ingredient and the excipient system.

An excipient change that improves tablet processing but alters particle dispersion, wetting, or dissolution could affect bioequivalence. The active ingredient cannot be treated as an ordinary high-solubility powder.

What excipients are used in GRIS-PEG tablets?

Public product labeling identifies inactive ingredients for GRIS-PEG tablets, but commercial excipient selection must be confirmed against the current FDA label and product-specific manufacturing documentation.[1]

Typical excipient functions relevant to the product include:

Excipient function	Formulation purpose
Diluent	Provides tablet mass and supports content uniformity
Binder	Improves granule and tablet strength
Disintegrant	Promotes tablet breakup after administration
Wetting agent	Improves contact between water and griseofulvin particles
Glidant	Improves powder flow during compression
Lubricant	Reduces sticking and ejection force
Coating system	Improves swallowability, appearance, and handling
Suspending agent	Required for a liquid or reconstitutable dosage form
Flavoring and sweetener	Supports pediatric acceptance
pH modifier or buffer	Controls suspension stability and palatability

The key technical limitation is that the excipient system must preserve rapid dispersion of ultramicrosize griseofulvin. Excessive hydrophobic lubricant, poor wetting, or overbinding can slow dissolution.

Which excipients are most important for griseofulvin absorption?

Wetting agents and disintegrants have the highest direct relevance to absorption. Suitable choices may include sodium lauryl sulfate, poloxamers, polysorbates, crospovidone, croscarmellose sodium, or sodium starch glycolate, subject to dosage, compatibility, and regulatory limits.

The selection should be based on dissolution performance rather than tablet hardness alone. A formulation with high mechanical strength can underperform if it delays tablet breakup or leaves agglomerated griseofulvin particles.

Hydrophilic binders such as povidone or hydroxypropyl cellulose can support granulation, but excessive binder levels may reduce porosity. Magnesium stearate and other hydrophobic lubricants require controlled blending because over-lubrication can retard wetting and dissolution.

What formulation patents protect GRIS-PEG?

The original chemical and ultramicrosize formulation concepts for griseofulvin date back many decades. The underlying active ingredient and early formulation patents are outside their original patent terms.

No modern, high-value composition-of-matter patent is expected to protect griseofulvin. Commercial protection is more likely to arise from:

• Product-specific manufacturing know-how
• Particle-size control
• Dissolution specifications
• Process controls
• Packaging and stability systems
• Trademark rights in the GRIS-PEG name
• Potential formulation or method-of-use patents, if any remain listed for a particular product

The Orange Book should be reviewed for current patent listings and exclusivity status for the relevant NDA. FDA’s Orange Book records patents and regulatory exclusivity associated with approved drug products, but an old product such as GRIS-PEG is unlikely to have meaningful active-ingredient exclusivity today.[2]

Does GRIS-PEG have method-of-use patent protection?

Griseofulvin’s core dermatophyte indications are established uses. Any original method-of-use protection would generally have expired. A later patent could theoretically cover a particular dosing regimen, population, or formulation, but such protection would need to be confirmed through current Orange Book and USPTO records.

The practical commercial barrier is therefore regulatory equivalence and product quality, not broad method-of-use exclusivity.

When does GRIS-PEG lose exclusivity?

GRIS-PEG’s new-drug exclusivity and original patent protection expired long ago. The product is not a biologic and does not receive the 12-year reference-product exclusivity framework applicable to biologics under the Public Health Service Act.

The relevant commercial position is:

Exclusivity category	GRIS-PEG assessment
New chemical entity exclusivity	Expired
Original composition patent	Expired
Pediatric exclusivity	No current commercial significance
Orphan-drug exclusivity	Not applicable
Biologic reference-product exclusivity	Not applicable
Generic substitution opportunity	Established, subject to FDA approval
Trademark protection	Potentially remains for the GRIS-PEG name

A competitor does not need a biosimilar application. It would pursue an ANDA or, for a materially different dosage form, a separate NDA or other applicable FDA pathway.

How many patents cover GRIS-PEG?

The number of currently relevant patents cannot be inferred from historic patent references alone. The commercial analysis should distinguish between expired griseofulvin patents, active manufacturing patents, Orange Book-listed patents, and trademark rights.

For business purposes, the estate should be treated as weak at the active-ingredient level unless a current, enforceable formulation or process patent is identified. Patent risk may still arise from:

• A narrow particle-size distribution claim
• A specific granulation or milling process
• A controlled-release formulation
• A pediatric suspension system
• A combination product
• A patented dosing regimen
• Trade-secret manufacturing controls

Patent exhaustion is not the main issue for a generic manufacturer. The core requirement is to produce a product that meets FDA quality and bioequivalence standards without infringing a live claim.

What is the FDA and Orange Book status of GRIS-PEG?

GRIS-PEG is an FDA-approved prescription product associated with griseofulvin ultramicrosize tablets. FDA product records, the current prescribing information, and the Orange Book determine the active marketing, reference-product, patent, and exclusivity status.[1,2]

The regulatory landscape has four relevant layers:

1. The reference product’s approved strength and dosage form.
2. Available generic griseofulvin ultramicrosize products.
3. FDA’s therapeutic-equivalence evaluations.
4. Any current patents or exclusivity codes in the Orange Book.

Generic applicants must address the product-specific bioequivalence risk created by low solubility and particle-size dependence. Conventional in vitro testing may be insufficient if dissolution is highly sensitive to particle aggregation or excipient selection.

Are Paragraph IV challenges relevant?

Paragraph IV certification is relevant only if a listed patent remains in force and is listed against the reference product. For an old griseofulvin product, the principal commercial pathway is more likely ordinary ANDA approval or approval against expired patents.

If an active Orange Book patent exists, an ANDA applicant may certify that the patent is invalid, unenforceable, or will not be infringed. The reference sponsor could then bring Hatch-Waxman litigation, potentially triggering a 30-month stay under applicable conditions.[3]

No current litigation or settlement should be assumed without a live review of FDA, PACER, and Orange Book records.

What excipient strategies can differentiate a GRIS-PEG competitor?

1. Improve dissolution without changing the active ingredient

The most direct strategy is to preserve ultramicrosize griseofulvin while improving wetting and tablet breakup.

Potential tools include:

• Controlled surfactant concentration
• More efficient disintegrant combinations
• Porous granulation
• Reduced hydrophobic lubricant exposure
• Direct compression with optimized particle engineering
• Co-processing with a hydrophilic carrier

The target is faster and more reproducible dissolution, not simply smaller particles.

2. Reduce food-related variability

Griseofulvin exposure can increase with fatty food. A formulation that reduces dependence on meal composition could have clinical and commercial value, but it would require comparative pharmacokinetic work.

Possible approaches include:

• Lipid-based self-emulsifying systems
• Amphiphilic excipients
• Solid dispersions
• Spray-dried polymer dispersions
• Surfactant-assisted granules
• Lipid or lipid-polymer multiparticulates

These approaches may create a new formulation rather than a straightforward generic equivalent. The regulatory burden would rise if the product departs materially from the reference dosage form.

3. Develop a pediatric oral liquid

A ready-to-use or reconstitutable suspension could address patients who cannot swallow tablets. The main excipient challenges are:

• Uniform suspension over the labeled dosing interval
• Taste masking
• Sedimentation and redispersion
• Microbial control
• Chemical and physical stability
• Accurate dosing with an oral syringe
• Avoidance of excessive viscosity

Suitable platform components may include xanthan gum, microcrystalline cellulose and carboxymethylcellulose systems, poloxamers, sucrose or polyols, flavor systems, and approved preservatives. The product must maintain dose uniformity after shaking and remain acceptable to pediatric patients.

A pediatric suspension could be commercially differentiated even where tablet competition is strong.

4. Develop an orally disintegrating or mini-tablet product

An orally disintegrating tablet or small-dose mini-tablet could target pediatric and geriatric use. The principal risk is that highly porous tablets may disperse griseofulvin efficiently but produce an unacceptable mouthfeel.

Potential solutions include:

• Taste-masked granules
• Polymer coatings
• Ion-exchange or lipid-based masking systems
• Mannitol-based orally disintegrating matrices
• Low-force compression
• Rapidly dispersing but non-gritty particles

The 125 mg strength is particularly relevant to dose flexibility. A scored or multiparticulate product could permit more precise pediatric dosing.

5. Remove excipient liabilities

A differentiated generic may pursue:

• Lactose-free formulation
• Sugar-free suspension
• Lower sodium formulation
• Gluten-free manufacturing controls
• Reduced preservative load
• Dye-free tablets
• Alcohol-free liquid
• Improved allergen labeling

These features are commercially useful only if they preserve dissolution and stability. They are unlikely to support premium pricing by themselves in a heavily genericized market.

What manufacturing and intellectual-property barriers exist?

The principal manufacturing barriers are technical rather than patent-based.

Barrier	Commercial impact
API particle-size control	Direct effect on dissolution and exposure
Agglomeration during processing	Can reduce effective surface area
Lubricant over-blending	May delay wetting and tablet breakup
Content uniformity	Important at the 125 mg strength
Milling and containment	Adds equipment and validation costs
Suspension sedimentation	Limits liquid-product usability
Taste masking	May increase process complexity
Stability of micronized API	Requires control of moisture and electrostatic behavior
Bioequivalence	Can delay generic approval
Supplier qualification	Particle-size drift can change product performance

A manufacturer should treat ultramicrosize griseofulvin as a critical material attribute. Incoming API specifications should cover particle-size distribution, specific surface area, polymorphic form where relevant, moisture, bulk density, and dissolution behavior.

Process analytical technology may be justified for milling, blending, granulation, and lubrication. These controls can create defensible know-how even when the formal patent estate is weak.

Which companies are challenging GRIS-PEG?

The competitive field includes generic manufacturers of griseofulvin ultramicrosize tablets and potential developers of liquid or modified-release products. Competition is likely to be fragmented because griseofulvin is an old, low-growth anti-infective product with limited pricing power.

The most relevant competitor categories are:

1. Generic tablet manufacturers.
2. Contract developers offering pediatric suspensions.
3. Specialty dermatology companies with branded reformulations.
4. API suppliers with controlled particle-size capabilities.
5. Compounding pharmacies serving pediatric and swallowing-impaired patients.

The presence of a generic product does not eliminate an opportunity for a better dosage form. It reduces the value of an undifferentiated tablet and increases the value of convenience, tolerability, supply reliability, and reimbursement access.

What licensing deals could create commercial value?

Licensing opportunities are more likely to involve formulation platforms than GRIS-PEG’s historical brand rights.

Potential deal structures include:

Licensing asset	Likely partner
Micronization or particle-engineering process	Generic manufacturer
Pediatric suspension technology	Dermatology or pediatric specialty company
Taste-masking platform	Formulation technology company
Lipid-based absorption system	Specialty pharmaceutical company
Manufacturing process and know-how	Contract manufacturing organization
Regional marketing rights	Generic or hospital supplier
Trademark or product rights	Specialty dermatology company

A licensee would need to establish freedom to operate around any live formulation claims and confirm that the proposed product does not require clinical development beyond the intended FDA pathway.

What generic launch scenarios exist for GRIS-PEG?

Scenario 1: Standard ultramicrosize tablet

This is the lowest-risk regulatory approach and the most exposed to price competition. Success depends on reliable supply, low manufacturing cost, and pharmacy substitution.

Scenario 2: Differentiated pediatric suspension

This offers stronger product differentiation and may support specialty distribution. The risks are stability, taste, microbial control, and a more demanding regulatory package.

Scenario 3: Orally disintegrating tablet or mini-tablet

This could target adherence and swallowing limitations. The main risks are taste, grittiness, dose uniformity, and the need to demonstrate comparable exposure.

Scenario 4: Food-independent formulation

This has the highest technical and commercial upside but may require a new formulation development program, comparative pharmacokinetics, and potentially a separate NDA strategy.

Scenario 5: Institutional or shortage-resilience supply

Hospitals and public-sector buyers may value a reliable supplier more than a novel excipient system. The opportunity depends on procurement contracts, manufacturing economics, and supply-chain performance.

How does GRIS-PEG compare with other oral antifungals?

Product class	Main formulation advantage	Main commercial limitation
Griseofulvin ultramicrosize	Established pediatric and dermatophyte use	Poor solubility and treatment duration
Terbinafine tablets	Potent systemic antifungal activity	Different safety and monitoring profile
Itraconazole formulations	Broad antifungal activity	Complex absorption and interaction profile
Fluconazole	High oral bioavailability	Different indication and resistance considerations
Topical antifungals	Lower systemic exposure	Limited use for extensive or hair/nail infections

GRIS-PEG can remain relevant where clinicians value established pediatric experience or a specific dermatophyte indication. Its main weaknesses are treatment duration, absorption variability, and the limited commercial appeal of an old oral antifungal.

What is the revenue exposure and market opportunity?

GRIS-PEG is unlikely to support large-molecule revenue levels. The opportunity is better characterized as a focused specialty-generic or lifecycle-management asset.

Revenue potential depends on:

• Number of active generic competitors
• Pharmacy substitution rates
• Availability of the 125 mg and 250 mg strengths
• Pediatric demand
• Product shortages
• Payer coverage
• Retail versus institutional distribution
• Differentiation of the dosage form
• Ability to secure dermatology or pediatric channels

The best margin opportunity is likely a differentiated oral liquid, mini-tablet, or supply-constrained specialty product rather than another conventional tablet.

Key Takeaways

• GRIS-PEG contains griseofulvin ultramicrosize, making particle size and wetting central to product performance.
• The original active-ingredient and early formulation patent concepts are historically old; meaningful current exclusivity is unlikely.
• The strongest formulation opportunities are pediatric suspension, orally disintegrating or mini-tablet formats, and reduced food-effect systems.
• Excipients should be selected around dissolution, dispersion, taste, and stability rather than tablet hardness alone.
• Generic competition limits the value of an undifferentiated tablet.
• Manufacturing know-how around micronization, blending, lubrication, and dissolution may be more valuable than patent protection.
• Biosimilar risk does not apply.
• Commercial upside is concentrated in lifecycle reformulation, specialty distribution, and supply reliability.

FAQs

Can GRIS-PEG be reformulated with a different excipient system?

Yes. A reformulated product may use a different excipient system, but it must preserve product quality, dissolution, stability, and the applicable FDA bioequivalence requirements.

Is a liquid griseofulvin product commercially attractive?

A liquid product can address pediatric and swallowing-related demand. Its value depends on taste, suspension stability, dosing accuracy, shelf life, and reimbursement.

Does micronized griseofulvin require a special excipient strategy?

Yes. Ultramicrosize griseofulvin is sensitive to wetting, agglomeration, lubricant concentration, and granulation conditions. These variables can materially affect dissolution.

Can a GRIS-PEG generic receive Paragraph IV exclusivity?

Only if an ANDA applicant challenges a currently listed, unexpired Orange Book patent with a Paragraph IV certification. Historic patents that have expired cannot create new Paragraph IV exclusivity.

Is GRIS-PEG a suitable target for a 505(b)(2) product?

A 505(b)(2) strategy could be relevant for a materially different dosage form or delivery system, such as a novel suspension or absorption-enhanced product. A standard tablet intended to duplicate the reference product would generally fit the ANDA framework instead.

References

1. U.S. Food and Drug Administration. (n.d.). GRIS-PEG (griseofulvin ultramicrosize) tablets: Prescribing information. DailyMed.
2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. Orange Book.
3. U.S. Food and Drug Administration. (2015). Abbreviated new drug application submissions: Refuse-to-receive standards guidance for industry.
4. U.S. Pharmacopeial Convention. (2024). United States Pharmacopeia and National Formulary.
5. U.S. Food and Drug Administration. (n.d.). Inactive Ingredient Database.