List of Excipients in Branded Drug PRIMIDONE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	CELLULOSE, MICROCRYSTALLINE
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	LACTOSE MONOHYDRATE
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	MAGNESIUM STEARATE
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	METHYLCELLULOSE
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	SODIUM LAURYL SULFATE
Oceanside Pharmaceuticals	PRIMIDONE	primidone	68682-691	SODIUM STARCH GLYCOLATE TYPE A POTATO

Generic Drugs Containing PRIMIDONE

Company	Ingredient	NDC	Excipient
Lannett Company Inc	primidone	0527-1301	ACACIA
Lannett Company Inc	primidone	0527-1301	LACTOSE MONOHYDRATE
Lannett Company Inc	primidone	0527-1301	MAGNESIUM STEARATE
Lannett Company Inc	primidone	0527-1301	METHYLCELLULOSE
Lannett Company Inc	primidone	0527-1301	SODIUM STARCH GLYCOLATE TYPE A POTATO
Actavis Pharma Inc	primidone	0591-5321	CELLULOSE, MICROCRYSTALLINE

What are the Most Frequently-Used Excipients in PRIMIDONE?

# Of NDCs	Excipient
13	ACACIA
12	CELLULOSE, MICROCRYSTALLINE
2	DOCUSATE SODIUM
3	HYPROMELLOSE
7	HYPROMELLOSE 2910
3	HYPROMELLOSES

Excipient Strategy and Commercial Opportunities for Primidone

Last updated: February 25, 2026

What is the current excipient profile for Primidone?

Primidone, an anticonvulsant drug approved in 1954, has maintained a consistent formulation. Its formulation includes the API (primidone) with excipients such as lactose monohydrate, povidone (PVP K30), microcrystalline cellulose, talc, and magnesium stearate. These excipients facilitate tablet compression, stability, and bioavailability.

How does excipient selection impact Primidone’s manufacturing and stability?

Excipients influence tablet integrity, shelf life, and patient tolerability. In Primidone’s case:

• Lactose monohydrate acts as a filler but can cause issues in lactose-intolerant patients.
• Povidone improves disintegration and dissolution.
• Microcrystalline cellulose adds to mechanical strength.
• Talc functions as a glidant to improve flow.
• Magnesium stearate functions as a lubricant.

Regulatory agencies highlight the need for excipient compatibility to prevent interactions affecting efficacy or stability.

What are the commercial implications of excipient choices?

1. Patent opportunities: Modifying excipients can yield new formulations eligible for patent protection, extending exclusivity.
2. Formulation enhancements: Replacing lactose with an alternative filler (e.g., microcrystalline cellulose) to reduce excipient-related adverse effects increases market appeal for lactose-sensitive populations.
3. Differentiation: Developing controlled-release or minimally excipient formulations can distinguish products in a competitive market.
4. Supply chain advantages: Sourcing high-quality, cost-effective excipients ensures manufacturing reliability and reduces costs.

What are potential strategies for Excipient Innovation in Primidone?

• Reducing allergenic excipients: Replacing lactose with hypoallergenic fillers such as hypromellose or mannitol.
• Improving bioavailability: Using novel disintegrants or superdisintegrants to optimize dissolution.
• Enhanced stability: Incorporating excipients like antioxidants if formulation stability is an issue.
• Novel delivery systems: Formulating as an extended-release matrix or employing nanoparticle technology to improve pharmacokinetics.

What are market trends and opportunities regarding Primidone formulations?

Primidone’s use has declined in favor of newer anticonvulsants but remains in use in some developing markets. Opportunities lie in:

• Formulation modernization for improved patient compliance.
• Generic competition focusing on cost-effective excipient profiles.
• Off-label uses: Some indications may benefit from new formulations with tailored excipients.
• Expanding into niche markets like pediatric formulations with excipient adjustments for safety.

How do regulatory landscapes influence excipient strategies?

The U.S. FDA and EMA publish lists of acceptable excipients with limitations. Innovations must comply with:

• ICH guidelines (Q3A/Q3B) on impurities and stability.
• FDA Inactive Ingredient Database for excipient approval.
• Detailed Excipients Monograph for demonstrating safety profiles.

Failing to align with these standards can delay approval or lead to market rejection.

What are barriers to excipient innovation for Primidone?

• Manufacturing inertia: Existing processes may limit formulation flexibility.
• Regulatory hurdles: Extensive documentation needed to approve new excipients.
• Cost implications: R&D expenses versus market gains.
• Limited market size: Diminished incentives for extensive reformulation.

Key Takeaways

• Primidone's formulation relies on standard excipients with opportunities for innovation to improve tolerability, stability, and market differentiation.
• Patentable excipient modifications can extend market exclusivity.
• Market growth segments include niche formulations, including pediatric and controlled-release.
• Regulatory compliance remains critical; current standards restrict unapproved excipient use.

FAQs

1. Can replacing lactose in Primidone formulations increase marketability?
   Yes. Lactose-free formulations cater to lactose-intolerant patients, expanding patient base and market appeal.

2. Are there patent opportunities in Excipient modifications for Primidone?
   Potential exists if modifications demonstrate significant benefits or novel uses, providing new patent claims.

3. What excipients could replace talc as an glidant?
   Silicified microcrystalline cellulose or colloidal silicon dioxide serve as alternatives with similar functionalities.

4. How important is controlled-release technology for Primidone?
   It can enhance patient compliance and reduce dosing frequency, creating differentiation in the marketplace.

5. What regulatory challenges exist in excipient innovation?
   Demonstrating safety, compatibility, and stability of new excipients extends approval timelines and costs.

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References

[1] U.S. Food and Drug Administration. (2022). Inactive Ingredient Database. Retrieved from https://www.fda.gov/drugs/drug-approvals-and-databases/inactive-ingredient-database

[2] International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). (2003). Q3A(R2): Impurities in New Drug Substances.

[3] European Medicines Agency. (2021). Guideline on Excipients in the LABEL and Package Leaflet of Medicinal Products for Human Use.

[4] World Health Organization. (2013). Expert Committee on Specifications for Pharmaceutical Preparations: WHO Technical Report Series, No. 985.

[5] Watanabe, M., & Kondo, T. (2019). Advances in drug delivery systems: Novel approaches and their pharmaceutical applications. Drug Development and Industrial Pharmacy, 45(4), 563–578.