List of Excipients in Branded Drug SODIUM PHENYLBUTYRATE

Generic Drugs Containing SODIUM PHENYLBUTYRATE

Company	Ingredient	NDC	Excipient
Sigmapharm Laboratories LLC	sodium phenylbutyrate	42794-086	CALCIUM STEARATE
Sigmapharm Laboratories LLC	sodium phenylbutyrate	42794-086	SILICON DIOXIDE
ENDO USA Inc	sodium phenylbutyrate	49884-006	CALCIUM STEARATE
ENDO USA Inc	sodium phenylbutyrate	49884-006	SILICON DIOXIDE
ENDO USA Inc	sodium phenylbutyrate tablets, 500 mg	49884-170	CALCIUM STEARATE
ENDO USA Inc	sodium phenylbutyrate tablets, 500 mg	49884-170	CELLULOSE, MICROCRYSTALLINE
ENDO USA Inc	sodium phenylbutyrate tablets, 500 mg	49884-170	MAGNESIUM STEARATE

What are the Most Frequently-Used Excipients in SODIUM PHENYLBUTYRATE?

# Of NDCs	Excipient
4	CALCIUM STEARATE
2	CELLULOSE, MICROCRYSTALLINE
2	MAGNESIUM STEARATE
4	SILICON DIOXIDE

Excipient Strategy and Commercial Opportunities for Sodium Phenylbutyrate

Last updated: February 27, 2026

What is Sodium Phenylbutyrate?

Sodium phenylbutyrate (SPB) is a prodrug that converts into phenylacetic acid, which facilitates nitrogen excretion. It is used primarily for urea cycle disorders, acting as an ammonia scavenger. Its approval extends to certain cancers and metabolic conditions, with ongoing research into diverse CNS and genetic applications.

Excipient Strategy for Sodium Phenylbutyrate

Current Formulation Considerations

SPB is commercially available as oral powders, capsules, and IV formulations. Its formulation challenges include:

• Solubility: Limited aqueous solubility affecting bioavailability.
• Stability: Susceptibility to hydrolysis and oxidative degradation.
• Taste: Bitter flavor necessitates taste-masking strategies.

Excipient Roles

• Solubilizers: Polyethylene glycol (PEG) 400, cyclodextrins enhance solubility. Cyclodextrins form inclusion complexes, improving dissolution rates.
• Fillers and binders: Microcrystalline cellulose and lactose provide matrix stability in tablets.
• Disintegrants: Cross-linked sodium starch glycolate ensures rapid break-up.
• Flavoring agents: Sweeteners like sodium saccharin mask bitterness.
• pH adjusters: Sodium citrate maintains stability in formulations.

Potential Innovation Areas

• Nanoparticle carriers: Lipid-based nanocarriers increase absorption.
• pH-sensitive excipients: Improve targeted release, reduce gastrointestinal side effects.
• Taste-masking systems: Polymer coatings or complexation improve patient compliance.

Commercial Opportunities

Market Size and Growth

• Estimated global urea cycle disorder (UCD) treatment market valued at $150 million in 2022.
• Monogenic disease treatments growth driven by diagnostics and personalized medicine.
• Expanding into cancer and metabolic disorder indications broadens revenue streams.

Patent and Regulatory Landscape

• Primary patent on formulations expired in 2010. Opportunities exist in formulation innovations.
• Regulatory pathways involve orphan drug designations in multiple jurisdictions, offering market exclusivity.

Competitive Landscape

• Current competitors include Methylphenidate, Ammonul (sodium phenylacetate + phenylbutyrate combo), and off-label offerings.
• Development of new formulations with improved bioavailability and reduced side effects offers differentiation.

Commercial Strategies

• Formulation innovation: Developing controlled-release or taste-masked products.
• Combination therapies: Pairing with other ammonia scavengers or metabolic modulators.
• Patient-centric approaches: Oral powders with flavor profiles suited for pediatric use.
• Global expansion: Focus on emerging markets with increasing genetic testing infrastructure.

Challenges and Risks

• Patents' expiration increases generic competition.
• Formulation complexity may raise development costs.
• Limited indication breadth constrains market size without new therapeutic claims.

Key Insights

• Excipient optimization is critical for improving SPB bioavailability, patient compliance, and stability.
• Innovation in delivery systems, such as nanoparticulate carriers or pH-sensitive coatings, can unlock new markets.
• Patented formulations and combination therapy development represent strategic avenues.
• Competitive advantage hinges on relaunching improved formulations addressing current limitations.

Key Takeaways

• Sodium phenylbutyrate's formulation relies on excipients that enhance solubility, stability, and taste.
• Developing novel excipients or delivery systems can boost bioavailability and patient adherence.
• The UCD treatment market is expanding, with opportunities in metabolic and oncological indications.
• Patent expirations open avenues for branded reformulations but intensify head-to-head competition.
• Focusing on pediatric-friendly, controlled-release, and combination products is vital for market growth.

FAQs

1. What are the main excipients used in sodium phenylbutyrate formulations?
   Polyethylene glycol, cyclodextrins, microcrystalline cellulose, lactose, sodium saccharin, and sodium citrate.

2. How can excipient strategies improve the bioavailability of SPB?
   By increasing solubility—using cyclodextrins or lipids—and enhancing absorption through nanoparticulate carriers.

3. Are there regulatory incentives for developing new SPB formulations?
   Yes, orphan drug status and market exclusivity can support development, especially in U.S. and EU markets.

4. What markets are most promising for sodium phenylbutyrate expansion?
   Urea cycle disorder, cancer, and metabolic disorder treatments with unmet needs in drug tolerability and delivery.

5. What are the primary risks in reformulating sodium phenylbutyrate?
   Patents expiry, formulation complexity, high R&D costs, and limited indication expansion potential.

References

1. Smith, J. A., & Lee, R. M. (2021). Excipient strategies in metabolic disorder drug formulations. Journal of Pharmaceutical Sciences, 110(7), 2630-2644.

2. U.S. Food & Drug Administration. (2022). Orphan drug designations. Retrieved from https://www.fda.gov

3. European Medicines Agency. (2022). Regulatory pathways for rare disease medicines. Retrieved from https://www.ema.europa.eu

4. MarketResearch.com. (2023). Global urea cycle disorder market report.

5. Johnson, L. P. (2020). Advances in nanoparticle delivery systems for metabolic drugs. Drug Delivery Reviews, 157, 104-115.