List of Excipients in Branded Drug TRENTAL

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Validus Pharmaceuticals LLC	TRENTAL	pentoxifylline	30698-006	FD&C RED NO. 3
Validus Pharmaceuticals LLC	TRENTAL	pentoxifylline	30698-006	HYDROXYETHYL CELLULOSE
Validus Pharmaceuticals LLC	TRENTAL	pentoxifylline	30698-006	HYPROMELLOSE

Trental Excipient Strategy and Commercial Opportunities for Pentoxifylline

Last updated: October 5, 2026

Trental is the branded extended-release formulation of pentoxifylline, historically marketed at 400 mg strength for peripheral vascular disease and intermittent claudication. Its core composition is commercially mature, and the primary U.S. product has no meaningful remaining exclusivity. Commercial opportunities therefore depend on differentiated release technology, tolerability, dosage-form convenience, manufacturing cost, and geographic registration rather than brand protection.

What is Trental and how is pentoxifylline formulated?

Trental contains pentoxifylline, a methylxanthine derivative classified as a hemorheologic agent. In the United States, the reference product was Trental 400 mg extended-release tablets under NDA 018267. The FDA-approved indication covered symptomatic treatment of chronic occlusive arterial disease, including intermittent claudication. [1]

Pentoxifylline has high aqueous solubility relative to many modified-release drugs. The formulation challenge is therefore controlling rapid dissolution and maintaining exposure over an extended interval. The commercial product uses an oral extended-release tablet rather than an immediate-release capsule or liquid.

Attribute	Trental / pentoxifylline profile
Active ingredient	Pentoxifylline
Historic brand	Trental
Common strength	400 mg
Dosage form	Extended-release oral tablet
Original U.S. NDA	018267
Therapeutic area	Peripheral arterial disease and intermittent claudication
Primary formulation objective	Prolonged release and reduced dosing frequency
U.S. patent position	No material live exclusivity identified for the legacy product
Current competitive basis	Generic price, supply reliability, tolerability, and dosage-form differentiation

The branded U.S. product is listed by FDA as discontinued. Discontinuation from commercial distribution does not itself establish withdrawal for safety or efficacy reasons. Generic pentoxifylline extended-release tablets remain the relevant U.S. commercial reference for product development and substitution analysis. [2]

What excipients are used in pentoxifylline extended-release tablets?

Pentoxifylline extended-release tablets generally use hydrophilic polymer matrices and conventional tablet-processing excipients. Commercial labels vary by manufacturer, and the exact Trental composition should not be assumed to match every generic product.

Common excipient classes include:

Excipient class	Typical function	Relevance to pentoxifylline
Hypromellose	Hydrophilic matrix former	Controls water penetration, gel formation, and drug diffusion
Microcrystalline cellulose	Diluent and compression aid	Supports tablet strength and content uniformity
Povidone	Binder	Improves granule formation and mechanical integrity
Colloidal silicon dioxide	Glidant	Improves powder flow
Magnesium stearate	Lubricant	Reduces tooling adhesion and ejection force
Talc	Processing aid or anti-adherent	Improves manufacturing performance
Polyethylene glycol	Film-coating plasticizer or coating component	Supports flexible, smooth coating
Titanium dioxide or approved colorants	Opacifier or colorant	Supports product identification and light protection

DailyMed labels for generic pentoxifylline extended-release tablets identify excipient combinations that include hypromellose, microcrystalline cellulose, povidone, magnesium stearate, colloidal silicon dioxide, talc, polyethylene glycol, and coating materials. The list is manufacturer-specific and can change with a supplemental filing or site transfer. [3]

How does a hydrophilic matrix control pentoxifylline release?

After ingestion, water enters the tablet and hydrates the hypromellose matrix. The polymer swells and forms a viscous gel layer. Pentoxifylline then leaves the tablet through a combination of diffusion, erosion, and matrix relaxation.

The key formulation variables are:

• Polymer viscosity grade.
• Polymer concentration.
• Tablet porosity and compression force.
• Drug-to-polymer ratio.
• Granulation method.
• Lubricant level.
• Coating weight.
• Tablet dimensions.
• Dissolution medium and agitation conditions.

Pentoxifylline’s relatively high solubility creates a risk of excessive early release if the matrix is under-polymerized or too porous. A robust product must control the initial release phase without causing excessive residual drug at later time points.

What excipient strategy is most suitable for a Trental follow-on product?

The lowest-risk strategy is a conventional hydrophilic matrix tablet using hypromellose with standard direct-compression or wet-granulation excipients. This approach aligns with established regulatory precedent and avoids unnecessary development risk.

A differentiated product can use one of four strategies:

Conventional hydrophilic matrix

This is the most practical strategy for a generic or value-line product. It offers:

• Established manufacturing equipment.
• Familiar excipient safety profiles.
• Straightforward scale-up.
• Conventional dissolution testing.
• Lower development cost.

The main commercial limitation is limited differentiation. A product using the same 400 mg extended-release strength will compete primarily on price and supply.

Multi-particulate modified release

Pellets, granules, or coated particles can provide more flexible release control. The technology may support capsules, sachets, or sprinkle formulations. It can also reduce sensitivity to tablet-level mechanical defects.

The disadvantages are higher manufacturing cost, more complex process validation, and a greater need to demonstrate dose uniformity and release consistency.

Osmotic or membrane-controlled release

An osmotic tablet or coated reservoir system could produce a more predictable release profile across gastrointestinal conditions. This technology may support a new 505(b)(2) or equivalent reformulation pathway if the product has meaningful clinical or pharmacokinetic differentiation.

The commercial case is weaker if the target population has no demonstrated adherence problem or if conventional generic products already achieve adequate exposure.

Abuse-deterrent or gastroretentive design

These strategies are technically possible but poorly aligned with the existing Trental market. Pentoxifylline is not generally positioned as a high-abuse drug, and a gastroretentive system would require a clear pharmacokinetic and clinical rationale.

What formulation patents protect Trental and pentoxifylline products?

The legacy Trental product does not appear to have a commercially relevant active U.S. patent estate. The original product and its extended-release concept date from an era when any relevant composition, formulation, or use patents would generally have expired.

The practical patent landscape is:

Protection category	Trental position
Active-ingredient patent	Expired
Original extended-release product protection	Expired or no longer commercially material
U.S. Orange Book exclusivity	No current meaningful exclusivity identified
Generic blocking patent	No material blocking patent identified
New formulation patent	Available only for a genuinely novel product
Method-of-use patent	Potentially available for a new, non-obvious indication, but not for the established use alone
Manufacturing patent	Possible for a novel process, but unlikely to block conventional generic entry

A new patent could cover a specific polymer combination, coating system, multiparticulate architecture, particle-size distribution, dissolution profile, or manufacturing process. Patentability would depend on novelty, non-obviousness, enablement, and claim scope. A broad claim covering pentoxifylline extended release generally would face substantial prior-art risk.

What is the Orange Book status of Trental?

Trental’s U.S. exclusivity position is effectively exhausted. FDA Orange Book treatment distinguishes between an approved reference product, products discontinued from marketing, and active listed products. The historic Trental NDA is relevant as the reference-product history, but the commercial market is supplied by abbreviated new drug applications for pentoxifylline extended-release tablets. [2]

No current pediatric exclusivity, orphan exclusivity, or new chemical entity exclusivity is associated with Trental. Any generic manufacturer seeking approval would generally rely on the established pentoxifylline product and satisfy the applicable abbreviated approval requirements.

Are there Paragraph IV challenges for Trental?

Paragraph IV litigation is not a major current risk category for legacy pentoxifylline extended-release products because the key product and use patents have expired or are not commercially blocking. Generic entrants are more likely to face ordinary ANDA review, manufacturing compliance, bioequivalence questions, and market-pricing pressure than patent litigation.

A new differentiated formulation could create Paragraph IV exposure if the developer lists formulation or method patents in the Orange Book. That risk would arise from the new product’s patent strategy, not from the legacy Trental product.

When does Trental lose exclusivity?

Trental’s material U.S. exclusivity has already expired. The product is not an active branded exclusivity opportunity. Pentoxifylline is a mature generic active ingredient, and commercial entry is principally constrained by manufacturing economics, regulatory execution, and market size.

Milestone	Commercial implication
Original FDA approval	Established the reference product
Expiration of historical product protection	Enabled generic competition
Reference product discontinuation	Reduced brand-based substitution value
Current generic availability	Shifted competition to price and supply
New formulation development	Could create a separate patent and regulatory asset

Exact historical patent expiration dates for the original Trental estate are not commercially determinative because the protection has already lapsed.

What FDA regulatory pathway applies to new pentoxifylline products?

A conventional 400 mg extended-release tablet can generally pursue an ANDA if it is therapeutically equivalent to the reference product and meets FDA requirements for pharmaceutical equivalence, bioequivalence, quality, and manufacturing control.

A materially different product may require a 505(b)(2) application if it relies in part on FDA findings for pentoxifylline but introduces a new dosage form, release mechanism, route, strength, or clinical use. The pathway depends on the degree of difference and the reference data available.

Potential development routes include:

Product concept	Likely regulatory logic
Conventional 400 mg extended-release tablet	ANDA-oriented
New polymer matrix with equivalent performance	Potential ANDA if equivalence is established
Sprinkle capsule or multiparticulate product	505(b)(2) or ANDA analysis required
Oral liquid	Likely new formulation pathway; dose uniformity and stability are central
New indication	505(b)(2) or full application depending on reliance and data
New strength or dosing regimen	Regulatory pathway depends on equivalence and clinical support

The development program should prioritize dissolution method development, fed and fasting pharmacokinetics, food-effect characterization, alcohol-dose dumping assessment where relevant, stability, and in vitro-in vivo correlation.

What commercial opportunities exist for Trental excipients?

The strongest opportunities are formulation-led rather than molecule-led.

Low-cost generic platform

An excipient supplier can target manufacturers that need a reliable hypromellose matrix system, direct-compression diluent, or low-metal pharmaceutical lubricant. The value proposition is process consistency, not patent exclusivity.

Improved gastrointestinal tolerability

Pentoxifylline can cause nausea, dyspepsia, dizziness, and other adverse effects. A formulation that reduces high early exposure or minimizes tablet disintegration variability may offer commercial value, but it would require comparative pharmacokinetic and clinical evidence.

Food-effect and release robustness

A polymer system that maintains release across fed and fasting conditions could support a differentiated label or stronger product positioning. This is a technically credible opportunity, but the commercial benefit must exceed the cost of a new regulatory package.

Alternative dosage forms

Potential niche products include:

• Smaller tablets for swallowing convenience.
• Multiparticulate capsules.
• Sprinkle formulations for patients with swallowing difficulty.
• Modified-release tablets with improved scoreability, if technically feasible.
• Lower-strength products for titration or renal-function management.

Each option must address dose accuracy, dose dumping, stability, and substitution rules.

Regional supply and licensing

Pentoxifylline remains marketed in multiple countries under Trental and generic names. Commercial opportunities may exist in markets where branded supply is limited, generic competition is fragmented, or local manufacturing is favored.

Licensing value would be higher for a protected delivery system, differentiated dosage form, or regional registration package than for an unprotected conventional tablet. A simple excipient substitution is unlikely to command substantial upfront economics unless it solves a documented manufacturing or supply problem.

How does Trental compare with competing peripheral vascular drugs?

Pentoxifylline competes with pharmacologic and non-pharmacologic management of intermittent claudication. Cilostazol has stronger positioning in some markets for intermittent claudication but carries important contraindications, including use restrictions in heart failure. Exercise therapy, smoking cessation, antiplatelet therapy, lipid management, and revascularization also affect the addressable market.

Product	Main commercial distinction	Excipient opportunity
Pentoxifylline ER	Mature, low-cost oral therapy	Manufacturing efficiency and adherence
Cilostazol	Alternative prescription therapy for claudication	Differentiated release and tolerability
Antiplatelet agents	Vascular risk reduction rather than direct claudication relief	Fixed-dose or combination concepts
Exercise and revascularization	Non-drug or procedural alternatives	Limited excipient relevance

Pentoxifylline’s low price limits premium reformulation potential. A successful product would need a clear benefit in administration, tolerability, availability, or regional access.

What generic launch risks exist for a new Trental product?

The principal risks are commercial and regulatory rather than patent-related.

1. The market is mature and price sensitive.
2. The reference brand has limited current commercial pull in the United States.
3. Multiple generic manufacturers can compete on the same strength and dosage form.
4. A novel excipient system may increase cost without creating reimbursed differentiation.
5. A 505(b)(2) product may require clinical evidence that is disproportionate to market size.
6. Generic substitution can limit brand recognition and pricing power.
7. Supply interruptions or raw-material changes can affect dissolution performance.

Manufacturing barriers remain relevant. Extended-release tablets require tight control of polymer distribution, granule moisture, compression force, tablet hardness, coating, and dissolution. A supplier that can provide reproducible release across sites may capture value even without owning a drug patent.

Key Takeaways

• Trental is the legacy brand for pentoxifylline extended-release tablets, historically supplied at 400 mg.
• The U.S. product has no meaningful remaining market exclusivity.
• Conventional formulations typically use hypromellose-based matrices with standard tablet excipients.
• The most practical excipient strategy is a robust hydrophilic matrix optimized for release control, manufacturability, and low cost.
• New commercial value would require a differentiated dosage form, improved tolerability, stronger release robustness, or regional market access.
• Patent opportunities exist for genuinely novel formulation or manufacturing systems, not for pentoxifylline extended release in general.
• Paragraph IV litigation is not a major current threat for the legacy product.
• An ANDA is the likely route for a therapeutically equivalent generic tablet; materially different products may require a 505(b)(2) pathway.
• The market is better suited to platform excipient supply, regional licensing, and low-cost generic manufacturing than to premium U.S. brand relaunch.

FAQs

Is Trental still available in the United States?

The original branded Trental product is listed as discontinued in the United States. Pentoxifylline extended-release generic products remain the relevant commercial products.

What is the standard Trental dose?

The historic standard presentation is a 400 mg extended-release tablet, generally administered according to the approved labeling and patient tolerability.

Can hypromellose be replaced in a pentoxifylline extended-release tablet?

Yes, but replacing hypromellose with another polymer or release-control system requires comparative dissolution, stability, manufacturing, and bioequivalence assessment. The replacement cannot be treated as an interchangeable excipient change without supporting data.

Does pentoxifylline have biosimilar risk?

No. Pentoxifylline is a chemically synthesized small molecule, not a biologic. Biosimilar pathways do not apply. Competition occurs through generic and reformulated-drug pathways.

Can a new Trental formulation receive patent protection?

Yes, a new formulation may receive patent protection if its composition, release mechanism, dosage form, or manufacturing process is novel and non-obvious. The patent would protect the new formulation, not the expired pentoxifylline molecule or the general concept of extended release.

References

1. U.S. Food and Drug Administration. (n.d.). Trental 400 mg extended-release tablets, NDA 018267: Prescribing information and regulatory history. FDA Drugs@FDA.

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

3. National Library of Medicine. (n.d.). Pentoxifylline extended-release tablets: DailyMed labeling and inactive ingredients. DailyMed.

4. U.S. Food and Drug Administration. (n.d.). Inactive ingredient database. FDA.