List of Excipients in Branded Drug CILOSTAZOL

« Back to Dashboard

Generic Drugs Containing CILOSTAZOL

Company	Ingredient	NDC	Excipient
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	CELLULOSE, MICROCRYSTALLINE
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	CROSCARMELLOSE SODIUM
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	HYPROMELLOSE
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	LACTOSE MONOHYDRATE
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	MAGNESIUM STEARATE
West-Ward Pharmaceuticals Corp	cilostazol	0054-0028	SILICON DIOXIDE

What are the Most Frequently-Used Excipients in CILOSTAZOL?

# Of NDCs	Excipient
5	CARBOXYMETHYLCELLULOSE CALCIUM
19	CELLULOSE, MICROCRYSTALLINE
10	CROSCARMELLOSE SODIUM
14	CROSPOVIDONE
2	HYPROMELLOSE
1	HYPROMELLOSE 2910

Cilostazol Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

Cilostazol is an established generic cardiovascular drug with limited remaining composition-of-matter exclusivity and substantial room for formulation differentiation. The main technical problem is poor aqueous solubility combined with clinically relevant food and metabolic effects. The strongest commercial opportunities are immediate-release tablets with improved dissolution consistency, lower food sensitivity, easier swallowing, lower-cost manufacturing, and differentiated presentations such as orally disintegrating or sprinkle-capable products.

What is cilostazol and how is it marketed?

Cilostazol is a selective phosphodiesterase-3 inhibitor approved in the United States to reduce symptoms of intermittent claudication in patients with peripheral arterial disease. The reference product is Pletal, marketed by Otsuka Pharmaceutical. FDA-approved strengths are 50 mg and 100 mg tablets, administered twice daily at least 30 minutes before or two hours after breakfast and dinner.[1]

Attribute	Cilostazol
Active ingredient	Cilostazol
Pharmacological class	PDE3 inhibitor
Main indication	Intermittent claudication associated with peripheral arterial disease
Reference product	Pletal
U.S. strengths	50 mg and 100 mg tablets
Typical dosage	100 mg twice daily
Dose reduction	50 mg twice daily with strong CYP3A4 or CYP2C19 inhibitors
Dosage form	Immediate-release oral tablet
Key formulation issue	Low aqueous solubility and food-dependent exposure
Major safety restriction	Contraindicated in patients with heart failure of any severity

Cilostazol is metabolized primarily through CYP3A4 and CYP2C19. Exposure increases with strong inhibitors of these pathways, which explains the labeled dose reduction.[1] The drug is also contraindicated in heart failure because of the class-related risk associated with PDE3 inhibition.

What excipient properties matter most for cilostazol tablets?

Cilostazol formulation development should prioritize dissolution, particle dispersion, blend uniformity, tablet robustness, and control of food-related variability. Excipient selection should support a rapid and reproducible release profile without creating excessive manufacturing complexity.

Cilostazol is practically insoluble in water. Its bioavailability is affected by food, particularly high-fat meals, which can increase exposure and peak concentration.[1] The formulation objective is therefore not simply to produce a hard, stable tablet. It is to produce a dosage form that delivers consistent drug release across physiological and manufacturing conditions.

Solubility and wetting

Potential excipient classes include:

• Wetting agents such as sodium lauryl sulfate, poloxamers, or selected nonionic surfactants.
• Hydrophilic polymers such as povidone, copovidone, or low-viscosity hydroxypropyl methylcellulose.
• Superdisintegrants such as crospovidone, croscarmellose sodium, and sodium starch glycolate.
• Water-soluble fillers such as lactose, mannitol, or selected grades of microcrystalline cellulose.
• Lipid or self-emulsifying components for advanced formulations.

Surfactants can improve wetting and dissolution, but excessive levels may reduce tablet strength, alter powder flow, create foaming during dissolution testing, or increase sensitivity to lubricant overmixing. Sodium lauryl sulfate can be effective at low concentrations but requires control of particle size, grade, and distribution.

Particle engineering

Micronized cilostazol can increase surface area and improve dissolution without changing the chemical entity. The commercial risks are electrostatic charging, agglomeration, poor flow, dust generation, and content-uniformity failures at low drug loading.

Wet milling, dry milling, spray drying, or co-precipitation can create stronger differentiation than conventional excipient substitution. These approaches also increase development and scale-up costs. A sponsor should establish a clear link between particle-size distribution, specific surface area, dissolution, and pharmacokinetic performance.

Disintegration and tablet robustness

Immediate-release products require rapid tablet breakup while maintaining mechanical integrity during coating, packaging, transport, and handling. Crospovidone is often useful where rapid capillary action and low swelling are preferred. Croscarmellose sodium and sodium starch glycolate can provide strong disintegration but may be more sensitive to compression force, moisture, and formulation composition.

Microcrystalline cellulose can improve compactibility. Mannitol can support a pleasant mouthfeel and is useful for orally disintegrating tablets, but it can increase tablet friability unless balanced with a suitable binder. Lactose offers good compressibility in some systems but can participate in Maillard reactions with certain amine-containing drug substances. Cilostazol-specific compatibility testing is required before selecting lactose as the primary filler.

What excipient strategies are available for cilostazol?

Conventional immediate-release tablet

The lowest-risk approach is a conventional tablet using a filler, binder, disintegrant, glidant, lubricant, and optional wetting agent. This strategy offers the lowest cost and the simplest regulatory pathway.

A representative development architecture could include:

Functional role	Candidate excipients
Diluent	Microcrystalline cellulose, lactose, mannitol, dibasic calcium phosphate
Binder	Povidone, copovidone, hydroxypropyl cellulose
Disintegrant	Crospovidone, croscarmellose sodium, sodium starch glycolate
Wetting agent	Sodium lauryl sulfate, poloxamer
Glidant	Colloidal silicon dioxide
Lubricant	Magnesium stearate, sodium stearyl fumarate
Film coating	Hypromellose, polyethylene glycol, titanium dioxide or approved colorants

The most practical design space is a direct-compression or dry-granulated tablet with low surfactant loading and a superdisintegrant system. The manufacturing process should limit magnesium stearate exposure because over-lubrication can slow dissolution.

Wet-granulated tablet

Wet granulation can improve flow and content uniformity when micronized cilostazol is difficult to process. It can also distribute surfactants and polymers more uniformly. The tradeoffs are additional processing time, solvent or water exposure, drying costs, and possible changes in particle morphology.

Aqueous granulation requires stability evaluation for hydrolysis, polymorphic conversion, agglomeration, and residual moisture. A dry-granulation process may be preferable where moisture sensitivity or solvent restrictions are material.

Amorphous solid dispersion

An amorphous solid dispersion can improve apparent solubility and dissolution by dispersing cilostazol in a polymeric matrix. Candidate carriers include copovidone, hydroxypropyl methylcellulose acetate succinate, and hot-melt-extrusion polymers.

This route can support a smaller tablet or more robust dissolution profile, but it introduces physical-stability risk. The development program must control recrystallization, residual solvent, glass-transition behavior, moisture uptake, and storage performance. The regulatory burden is also higher than for a conventional generic tablet.

Lipid-based or self-emulsifying formulation

A lipid-based system may improve dissolution of poorly soluble cilostazol by maintaining the drug in a solubilized state. Candidate materials include medium-chain triglycerides, mono- and diglycerides, nonionic surfactants, and co-solvents.

The main commercial risk is that lipid excipients may amplify rather than reduce food-related exposure if the formulation does not adequately control drug precipitation after dispersion. A self-emulsifying system is better positioned as a differentiated product than as the lowest-cost generic.

Orally disintegrating tablet

An orally disintegrating tablet could target patients with dysphagia, elderly patients, and caregivers seeking easier administration. Mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and taste-masking polymers are relevant excipient classes.

Cilostazol has a drug-specific taste and may require polymer coating, ion-complexation, flavoring, or a multiparticulate approach. The tablet must disintegrate rapidly without generating an unacceptable mouthfeel. Dose size is a constraint, particularly for the 100 mg strength.

What formulation patents protect cilostazol products?

The original cilostazol composition-of-matter and early formulation patent protection is generally understood to have expired in major markets. Current commercial barriers are more likely to involve process patents, specific solid forms, particle-size control, excipient ratios, dissolution specifications, combination products, or delivery technologies than basic cilostazol ownership.

A sponsor should separate three categories of intellectual property:

1. Expired compound and early use patents covering cilostazol itself.
2. Potentially enforceable formulation or manufacturing patents covering a specific product architecture.
3. Regulatory exclusivity and Orange Book-listed patents associated with an approved product.

Generic applicants should review the current FDA Orange Book, patent listings for the relevant reference product, FDA approval letters, and patent-family records before selecting a Paragraph IV strategy.[2] A conventional cilostazol tablet made with well-known excipient classes is unlikely to produce a strong composition patent unless the claims are tied to a narrowly defined dissolution, particle, process, or stability limitation.

How strong is the patent estate for cilostazol?

The core patent estate is weak for blocking ordinary generic entry because cilostazol has been marketed for decades and multiple generic products exist. A new patent position would be stronger if it demonstrated:

• A measurable reduction in food-effect variability.
• A specific particle-size or solid-state property linked to clinical performance.
• A narrow dissolution profile that is difficult to reproduce.
• Improved stability under accelerated and long-term conditions.
• A clinically relevant advantage in swallowing, adherence, or dose administration.
• A manufacturing process that produces a controlled and non-obvious material attribute.

Broad claims to routine fillers, binders, lubricants, or disintegrants are vulnerable to novelty and obviousness challenges.

What is the FDA regulatory status of cilostazol products?

Cilostazol is an FDA-approved small-molecule drug and is eligible for the abbreviated new drug application pathway. A conventional generic tablet generally relies on pharmaceutical equivalence and bioequivalence rather than a new clinical-efficacy program.[3]

FDA review will focus on:

• Active ingredient identity and assay.
• Content uniformity.
• Dissolution and release performance.
• Impurity and degradation control.
• Stability.
• Bioequivalence.
• Manufacturing controls.
• Inactive-ingredient safety and suitability.

The FDA Inactive Ingredient Database can help establish precedent for excipient use by route and dosage form, but prior use does not eliminate the need to justify concentration, grade, function, and product-specific safety.[4]

What bioequivalence risks apply?

Cilostazol's low solubility and food sensitivity make dissolution a central bioequivalence risk. A formulation that dissolves rapidly in standard media but precipitates under physiologic conditions may not perform consistently in vivo.

Sponsors should evaluate:

• Multiple dissolution media and pH conditions.
• Agitation sensitivity.
• Surfactant concentration.
• Fed and fasted pharmacokinetics where required.
• Dose proportionality.
• Metabolite exposure where relevant.
• CYP2C19 and CYP3A4 interaction considerations.
• In vitro-in vivo relationships for advanced formulations.

A product that materially changes exposure may require a new drug application or a more complex regulatory strategy rather than a routine generic pathway.

What commercial opportunities exist for cilostazol excipient innovation?

Low-cost generic supply

The largest volume opportunity is a reliable, low-cost immediate-release tablet. Manufacturing advantages can come from direct compression, simplified coating, lower-cost excipient sourcing, and a robust dissolution profile that reduces batch failures.

Second-source and regional supply

Cilostazol is marketed globally under Pletal and generic names. Regional opportunities exist where supply is concentrated among a limited number of manufacturers, particularly for hospital, government, and tender markets. The commercial advantage is usually manufacturing reliability and price rather than premium formulation differentiation.

Patient-friendly dosage forms

Orally disintegrating, smaller, or sprinkle-capable products could address administration barriers. These products may obtain formulation or method-of-use protection if the claims are technically narrow and supported by clinical or usability data.

Food-effect reduction

A formulation that lowers the difference between fed and fasted exposure could support a stronger commercial position. The claim must be supported by pharmacokinetic data, not only dissolution testing. This opportunity is technically attractive but development-intensive.

Combination products

Cilostazol could be combined with antiplatelet or vascular medicines, but combination development introduces additional clinical, regulatory, safety, and patent complexity. Because cilostazol is contraindicated in heart failure and has interaction considerations, a combination product would require careful patient-selection and labeling analysis.

Which companies are challenging cilostazol market share?

The competitive field includes generic manufacturers supplying 50 mg and 100 mg tablets in the United States and other markets. Competition is primarily based on price, supply continuity, wholesaler access, tender participation, and manufacturing cost.

A definitive company-by-company ranking requires current market-share and shipment data. The more actionable competitive distinction is product architecture:

Competitor type	Main advantage	Main weakness
Conventional generic tablet	Lowest cost and regulatory risk	Limited differentiation
Branded reference product	Established prescriber recognition	Price premium
Regional generic supplier	Tender and local-market access	Geographic concentration
Specialty formulation developer	Patient-friendly or lower-food-effect product	Higher development cost
Contract manufacturer	Flexible capacity and lower fixed investment	Dependence on sponsor volumes

What generic entry risks exist for cilostazol?

Generic entry risk is high because the active ingredient is old, the main dosage form is simple, and multiple manufacturers can produce immediate-release tablets. The principal barriers are bioequivalence execution, supply economics, FDA manufacturing compliance, and market pricing.

A new entrant should expect:

• Rapid price erosion after additional approvals.
• Limited protection from routine excipient changes.
• Buyer concentration among wholesalers and payers.
• Margin pressure in 50 mg and 100 mg tablets.
• Greater value from differentiated delivery systems than from minor excipient substitutions.

How should a cilostazol excipient program be prioritized?

A practical development sequence is:

1. Establish a conventional immediate-release tablet as the reference formulation.
2. Screen wetting agents and superdisintegrants against particle-size variants.
3. Compare direct compression, dry granulation, and wet granulation.
4. Conduct stress stability and dissolution robustness testing.
5. Evaluate food-effect reduction only after the core formulation is stable.
6. Pursue an orally disintegrating or multiparticulate product if patient-access data supports the opportunity.
7. Build patent claims around measurable formulation attributes, process controls, and demonstrated performance.

The commercial case is strongest when excipient innovation reduces manufacturing cost or produces a clinically meaningful administration advantage. Routine substitution of one filler or lubricant for another is unlikely to create durable value.

Key Takeaways

• Cilostazol is an established, genericized PDE3 inhibitor marketed mainly as 50 mg and 100 mg immediate-release tablets.
• Poor aqueous solubility, food-dependent exposure, and metabolic interactions define the formulation strategy.
• Conventional tablets offer the lowest regulatory and manufacturing risk.
• Wetting agents, particle engineering, superdisintegrants, and controlled granulation are the main practical development levers.
• Amorphous dispersions and lipid systems may improve dissolution but carry higher stability and regulatory risk.
• Orally disintegrating and sprinkle-capable products offer the clearest patient-facing differentiation.
• Core cilostazol patent protection is weak for ordinary generic entry; new value must come from narrow formulation, process, solid-state, or administration claims.
• The strongest commercial opportunities are low-cost supply, regional sourcing, manufacturing reliability, and differentiated dosage forms.

FAQs

Can cilostazol be formulated as an orally disintegrating tablet?

Yes. Mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and taste-masking technologies are plausible development tools. The principal risks are taste, tablet size, friability, and preservation of bioequivalence.

Which excipient is best for improving cilostazol dissolution?

No single excipient is universally optimal. Low-level surfactants, particle-size reduction, hydrophilic polymers, and rapid disintegrants should be screened together because dissolution depends on the complete formulation and manufacturing process.

Does cilostazol have biosimilar risk?

No. Cilostazol is a chemically synthesized small molecule, not a biologic. Competitive risk comes from generic and reformulated small-molecule products rather than biosimilars.

Can a new cilostazol formulation receive patent protection?

Yes, if the formulation has novel and non-obvious technical characteristics. Stronger opportunities involve reduced food-effect variability, defined solid-state properties, improved stability, controlled particle size, or a clinically useful delivery format.

Is a cilostazol combination product commercially attractive?

It may be attractive in selected markets, but the development burden is higher than for a standalone generic. Drug interactions, heart-failure contraindication, clinical evidence, and combination-product patent exposure must be addressed.

References

1. U.S. Food and Drug Administration. (2023). Pletal (cilostazol) prescribing information. FDA/DailyMed.

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

3. U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals. FDA.

4. U.S. Food and Drug Administration. (2024). Inactive Ingredient Database. FDA.

5. European Medicines Agency. (2023). Cilostazol-containing medicinal products: Product information and regulatory assessment. EMA.

6. International Council for Harmonisation. (2009). Pharmaceutical development Q8(R2). ICH.

7. International Council for Harmonisation. (2023). Quality risk management Q9(R1). ICH.