List of Excipients in Branded Drug PASER

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Generic Drugs Containing PASER

Company	Ingredient	NDC	Excipient
Jacobus Pharmaceutical Company Inc	aminosalicylic acid	49938-107	CELLULOSE, MICROCRYSTALLINE
Jacobus Pharmaceutical Company Inc	aminosalicylic acid	49938-107	DIBUTYL SEBACATE
Jacobus Pharmaceutical Company Inc	aminosalicylic acid	49938-107	HYPROMELLOSE
Jacobus Pharmaceutical Company Inc	aminosalicylic acid	49938-107	METHACRYLIC ACID - ETHYL ACRYLATE COPOLYMER

What are the Most Frequently-Used Excipients in PASER?

# Of NDCs	Excipient
1	CELLULOSE, MICROCRYSTALLINE
1	DIBUTYL SEBACATE
1	HYPROMELLOSE
1	METHACRYLIC ACID - ETHYL ACRYLATE COPOLYMER

PASER Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

PASER is a 4-gram delayed-release granule formulation of aminosalicylic acid, also known as para-aminosalicylic acid or PAS, used with other drugs to treat multidrug-resistant tuberculosis. Its commercial differentiation depends primarily on enteric protection, moisture control, dose portability, and reliable delivery to the small intestine rather than on novel active-ingredient chemistry.

The strongest opportunity is a generic or reformulated PASER product that preserves intestinal release while improving sachet usability, stability, palatability, and manufacturing economics. PASER is a small-molecule product, so biosimilar competition does not apply. The principal competitive risk is an ANDA or 505(b)(2) product supported by formulation and bioequivalence data.

What is PASER and how is it formulated?

PASER contains 4 grams of aminosalicylic acid in delayed-release granules supplied in individual packets. The product is taken with acidic food or beverage and should not be chewed, crushed, or mixed with neutral or alkaline products because premature release can occur outside the intended gastrointestinal environment. The FDA label identifies the product as an enteric-coated, delayed-release formulation for oral use.[1]

The listed inactive ingredients include:

Excipient or excipient class	Formulation function
Methacrylic acid copolymer	Enteric-release polymer that dissolves at a higher intestinal pH
Dibutyl sebacate	Plasticizer that improves coating flexibility and reduces cracking
Povidone	Binder and granulation aid
Colloidal silicon dioxide	Glidant and flow-control agent
Talc	Anti-tacking and coating-process aid
Titanium dioxide	Opacifier and light-protection aid

The commercial formulation uses a multiparticulate design. Each granule must survive handling and gastric exposure, then release aminosalicylic acid after transit into a less acidic intestinal environment. The formulation therefore has more technical complexity than an immediate-release powder or conventional tablet.

What excipient strategy protects PASER performance?

The excipient strategy is centered on pH-dependent release and physical protection of the active ingredient.

Enteric polymer selection

Methacrylic acid copolymer is the principal functional excipient. It creates a coating that remains substantially intact in gastric fluid and dissolves at the target intestinal pH. A substitute manufacturer would need to demonstrate that a different polymer system produces comparable:

• Acid resistance
• Onset of release
• Release rate after pH transition
• Granule integrity
• Stability over shelf life
• Drug exposure and tolerability

Potential alternative polymers include methacrylic acid copolymers with different dissolution thresholds, cellulose acetate phthalate, polyvinyl acetate phthalate, and composite polymer systems. The commercial value of substitution depends on whether the alternative improves coating robustness, reduces processing cost, or avoids supply constraints without changing the product’s clinical performance.

Plasticizer control

Dibutyl sebacate improves flexibility in the enteric film. Its concentration affects coating elasticity, permeability, tackiness, and release. Excess plasticizer can soften the coating and increase moisture uptake. Insufficient plasticizer can produce brittle granules and premature release after storage or transport.

A generic developer could evaluate triethyl citrate, acetyl tributyl citrate, or other approved plasticizers. Any replacement would require comparative dissolution and stability data. Plasticizer substitution is unlikely to create meaningful exclusivity by itself, but it can improve manufacturability and support a formulation patent if combined with a defined polymer ratio, coating weight, or release profile.

Moisture and acid sensitivity

Aminosalicylic acid can present stability challenges related to moisture, heat, and chemical degradation. The enteric coating must protect the drug while avoiding excessive water ingress during manufacture and storage. The packet and secondary packaging are therefore commercially important.

Potential improvements include:

• High-barrier foil laminate sachets
• Desiccant-containing cartons
• Lower-water-activity granules
• Nitrogen-flushed packaging
• Improved sealing controls
• Unit-dose packaging with stronger humidity protection

Packaging changes can offer a faster route to product differentiation than a completely new dosage form. They may also support a supplement or 505(b)(2) strategy if the change produces a clinically relevant usability or stability benefit.

What formulation patents could protect a PASER competitor?

Patent protection would most plausibly arise from the formulation, manufacturing process, packaging, or method of administration rather than from aminosalicylic acid itself.

Potential claim area	Commercial value	Likely patent strength
Specific enteric polymer and plasticizer ratio	Moderate	Moderate if linked to a defined release profile
Narrow coating weight or particle-size distribution	Moderate	Moderate, but vulnerable to design-around
Moisture-stable granule architecture	High	Moderate to strong if supported by stability data
Taste-masked or pediatric granules	High	Stronger if clinically useful and technically distinct
Single-dose moisture-barrier sachet	Moderate	Moderate
Alternative release-pH profile	Moderate	Moderate
Manufacturing process with controlled coating uniformity	Moderate	Stronger if difficult to replicate
New aminosalicylic acid combination product	High	Potentially strong, subject to clinical and regulatory support

A robust formulation patent would need more than a list of conventional excipients. Useful claim features could include a defined active-to-polymer ratio, coating weight gain, dissolution limits in staged pH media, residual moisture level, storage stability, and granule-size distribution.

The main limitation is obviousness risk. Enteric polymers, plasticizers, talc, povidone, and silicon dioxide are established pharmaceutical tools. A patent based only on substituting one conventional excipient for another may face validity challenges unless the formulation produces an unexpected result.

When does PASER lose exclusivity and what is the Orange Book status?

PASER’s active pharmaceutical ingredient is an old small molecule. Its market protection is therefore driven primarily by regulatory status, manufacturing capability, and formulation barriers rather than by new-molecule exclusivity.

Public FDA product records identify PASER as a prescription delayed-release product associated with Jacobus Pharmaceutical Company.[1] Public Orange Book materials should be reviewed for the current reference-listed-drug designation, therapeutic-equivalence coding, and any listed patents or exclusivity. The available public product information does not indicate a meaningful period of remaining new chemical entity exclusivity for aminosalicylic acid.[2]

Exclusivity category	PASER relevance
New chemical entity exclusivity	Not a current commercial protection driver
Orphan-drug exclusivity	Not identified as the principal PASER protection
Pediatric exclusivity	No current extension identified in the cited public records
Orange Book patent term	Any protection would depend on listed formulation or use patents
Regulatory protection	ANDA approval requirements and reference-product reliance remain relevant
Trade-secret protection	Manufacturing controls, coating parameters, and supply chain may matter

Because the drug is an old active ingredient, a competing manufacturer would likely focus on an ANDA if it can demonstrate pharmaceutical equivalence and bioequivalence. A 505(b)(2) application could be appropriate for a materially different formulation, delivery system, administration method, or clinical use.

How many patents cover PASER?

No material active PASER patent estate is apparent from the public product information cited here. The absence of an identified Orange Book patent does not eliminate the possibility of non-listed patents, manufacturing know-how, foreign patents, or third-party rights.

The practical patent position is best characterized as follows:

Patent estate factor	Assessment
Active-ingredient composition patents	Weak or unavailable because aminosalicylic acid is old
Core enteric formulation patents	Potentially available to a competitor, but likely exposed to prior art
Method-of-use patents	Limited commercial leverage for an established tuberculosis use
Manufacturing patents	Possible protection around coating and stability controls
Packaging patents	Possible, but generally narrower
Freedom-to-operate risk	Requires a current patent search by jurisdiction and assignee

A competitor should not assume that an absence of Orange Book patents provides complete freedom to operate. Process patents, formulation patents, and foreign rights can remain relevant even when they do not block an ANDA in the United States.

What generic entry risks exist for PASER?

Generic entry risk is real but may be constrained by the product’s formulation complexity and small market size.

An ANDA applicant would need to address:

1. Pharmaceutical equivalence to the reference product.
2. Comparable delayed-release behavior.
3. Stability of the coated granules.
4. Product handling and packet performance.
5. Bioequivalence under an appropriate fed or fasting design.
6. Manufacturing reproducibility at commercial scale.

The product’s multiparticulate design may create a higher development burden than a simple tablet. The FDA’s product-specific guidance, if issued or updated, would be important in determining the required comparative dissolution and pharmacokinetic program.[3]

A generic applicant could pursue several entry models:

Entry model	Advantages	Constraints
Direct ANDA	Relies on the existing reference product	Requires close formulation and performance matching
505(b)(2) granules	Allows greater formulation differentiation	May require additional clinical or bridging data
Pediatric powder or suspension	Addresses swallowing and administration barriers	Taste, stability, and dose-uniformity risks
Institutional sachet product	Improves tuberculosis-program logistics	May require procurement and public-health contracting
Regional licensed product	Lower development cost in selected markets	Country-specific registration and supply requirements

Paragraph IV litigation is possible if an applicant certifies that a listed patent is invalid, unenforceable, or not infringed. If no blocking Orange Book patent is listed, the ANDA pathway may instead rely on Paragraph III or a certification that no patent information is applicable, depending on the FDA record at the time of filing.[2] No material PASER Paragraph IV litigation or settlement agreement is identified in the cited public sources.

What commercial opportunities exist for PASER excipient innovation?

The best opportunities are concentrated in adherence, logistics, and formulation robustness.

Pediatric and swallowing-friendly products

Tuberculosis treatment frequently involves prolonged multidrug regimens. PASER granules may be difficult for patients who have dysphagia, nausea, feeding-tube requirements, or taste sensitivity. A product that improves dispersion while preserving delayed release could address an important administration barrier.

Potential formats include:

• Smaller-dose sachets
• Taste-masked granules
• Sprinkle formulations
• Tube-compatible multiparticulates
• Ready-to-use acidic suspension systems
• Pediatric dose bands

Any product that changes the administration medium must preserve the acid-dependent protection of the granules. A neutral or alkaline vehicle could trigger premature dissolution.

Improved global supply-chain performance

PASER is suitable for an excipient and packaging redesign aimed at hot, humid markets. A higher-barrier sachet, improved coating uniformity, or enhanced storage stability could reduce product loss and simplify tuberculosis-program distribution.

Commercial buyers may value:

• Longer shelf life
• Reduced cold-chain dependence
• Lower breakage and packet leakage
• Easier inventory management
• Dose-level traceability
• Compatibility with public procurement specifications

Lower-cost manufacturing

The principal cost opportunity is process optimization. A manufacturer could reduce cost through higher coating efficiency, lower solvent use, shorter drying cycles, continuous fluid-bed processing, or improved granule yield.

The highest-value manufacturing patent would likely combine process parameters with a measurable product outcome, such as lower acid-stage release, tighter particle-size distribution, or improved stability after accelerated storage.

Combination products and regimen support

A fixed-dose combination involving aminosalicylic acid would face substantial clinical and regulatory complexity. The formulation could be difficult because PAS has distinct release requirements and potential compatibility issues with other antituberculosis actives.

A more practical opportunity may be coordinated co-packaging, adherence packaging, or digital dose tracking rather than a single combined dosage form.

How does PASER compare with other tuberculosis products?

PASER differs from standard tablets and capsules because the active ingredient is delivered as enteric-coated granules. That distinction creates both protection and development risk.

Product type	Release design	Main commercial advantage	Main limitation
PASER granules	Delayed release	Protects active ingredient from gastric conditions	More complex administration
Immediate-release PAS tablets	Rapid release	Simpler manufacturing	Greater gastric exposure and tolerability concerns
Injectable tuberculosis drugs	Parenteral	Avoids gastrointestinal delivery	Administration burden and safety concerns
Conventional oral tablets	Immediate or modified release	Familiar dosing and low packaging complexity	May not replicate PASER performance
Pediatric dispersible products	Modified oral delivery	Better usability	Taste and stability challenges

PASER’s defensibility is therefore functional rather than molecule-based. A competing product that matches the active ingredient but fails to reproduce acid protection, intestinal release, or acceptable administration may not be commercially equivalent.

What is the litigation and licensing outlook for PASER?

The public record cited here does not identify material current patent litigation involving PASER or a major public licensing transaction governing the product.[1,2] The more likely commercial pathway is private licensing of manufacturing know-how, regional distribution rights, or contract development and manufacturing capacity.

Potential licensing assets include:

• Enteric-coated granule technology
• High-barrier unit-dose packaging
• Pediatric taste-masking technology
• Tuberculosis-program distribution rights
• Regional registration dossiers
• Validated coating and stability processes

For an entrant, the most valuable deal structure would likely combine formulation rights with reliable active-ingredient supply and regulatory support in high-burden tuberculosis markets.

Key Takeaways

• PASER is a 4-gram delayed-release aminosalicylic acid granule product.
• Its core excipient strategy uses an enteric polymer, plasticizer, binder, glidant, anti-tacking agent, and opacifier.
• The strongest formulation opportunities involve coating robustness, moisture protection, pediatric usability, and packaging.
• PAS is an old small molecule, so new chemical entity exclusivity is not the primary barrier to competition.
• Generic entry is technically feasible but requires reliable multiparticulate coating and comparative release data.
• Biosimilar competition does not apply. The relevant threat is generic or 505(b)(2) competition.
• A new product would have stronger patent potential if it combines a defined excipient architecture with unexpected stability, release, or usability results.
• No material PASER patent litigation or public licensing transaction is identified in the cited sources.
• Commercial value is likely concentrated in tuberculosis-program procurement, global supply-chain performance, and patient administration improvements.

FAQs

Can PASER be reformulated as an immediate-release product?

An immediate-release product would not be a straightforward substitute because PASER’s delayed-release design is intended to protect administration and control gastrointestinal exposure. An immediate-release version would likely require a separate regulatory and clinical justification.

Which excipient is most important in PASER?

The methacrylic acid copolymer is the principal functional excipient because it controls resistance to gastric fluid and intestinal release. The plasticizer and coating-process excipients are also important for maintaining coating integrity.

Is PASER suitable for a 505(b)(2) application?

A 505(b)(2) pathway could be considered for a materially different granule, pediatric formulation, delivery system, or administration method. The regulatory burden would depend on the extent of formulation and clinical differences from the reference product.

Could a PASER generic use a different enteric polymer?

Potentially. A different polymer could be used if the resulting product meets applicable pharmaceutical equivalence, dissolution, stability, and bioequivalence requirements. A substitute polymer would not automatically avoid patent risk.

Does PASER have biosimilar competition?

No. PAS contains a chemically synthesized small-molecule active ingredient. Competition would proceed through generic or alternative regulatory pathways rather than the biosimilar pathway.

References

1. U.S. Food and Drug Administration. (n.d.). PASER (aminosalicylic acid) delayed-release granules prescribing information. Jacobus Pharmaceutical Company.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files

3. U.S. Food and Drug Administration. (n.d.). Product-specific guidances for generic drug development. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/product-specific-guidances-generic-drug-development