List of Excipients in Branded Drug ASACOL

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	FERRIC OXIDE RED
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	FERRIC OXIDE YELLOW
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	LACTOSE MONOHYDRATE
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	MAGNESIUM STEARATE
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	METHACRYLIC ACID - METHYL METHACRYLATE COPOLYMER
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	POLYETHYLENE GLYCOL
State of Florida DOH Central Pharmacy	ASACOL	mesalamine	53808-0205	POVIDONE

ASACOL Excipient Strategy and Commercial Opportunities in Mesalamine Drug Delivery

Last updated: August 6, 2026

Asacol is a legacy mesalamine delayed-release tablet platform whose commercial value rests on colonic targeting, manufacturing reproducibility, excipient substitution, and regulatory efficiency. The original brand has lost broad market exclusivity, while generic mesalamine delayed-release tablets and related products such as Asacol HD and Delzicol define the current competitive field. The strongest opportunities are in lower-cost enteric coatings, phthalate-free formulations, improved tablet robustness, differentiated dosing, and global regulatory bridging.

What is Asacol and how does its formulation work?

Asacol contains mesalamine, also called 5-aminosalicylic acid or 5-ASA, for the treatment of ulcerative colitis. Its formulation uses a pH-dependent delayed-release coating designed to resist release in the stomach and begin dissolving in the terminal ileum and colon.

The product strategy is based on three formulation requirements:

1. Protect mesalamine from early release in gastric fluid.
2. Deliver the active ingredient to the lower gastrointestinal tract.
3. Maintain dose uniformity, tablet integrity, and dissolution performance throughout shelf life.

Asacol 400 mg delayed-release tablets use a core containing mesalamine and conventional tablet excipients, surrounded by an enteric coating. The coating historically relied on methacrylic acid copolymer chemistry, commonly used to dissolve at a higher intestinal pH.

The commercial distinction is not the active ingredient. Mesalamine is an established small molecule with extensive generic competition. Differentiation comes from the delivery system, dose strength, tablet size, release profile, excipient composition, manufacturing process, and clinical labeling.

What excipients are used in Asacol formulations?

The inactive ingredients vary by product, strength, market, and manufacturing period. FDA labeling identifies conventional tablet excipients and enteric-coating materials for Asacol products.

Core tablet excipients

Historically disclosed Asacol tablet excipients include materials such as:

Formulation function	Representative excipient classes
Diluent	Lactose monohydrate, microcrystalline cellulose, dibasic calcium phosphate
Binder	Povidone
Disintegrant	Sodium starch glycolate or related superdisintegrants
Lubricant	Magnesium stearate
Glidant	Colloidal silicon dioxide
Pigment and opacity agent	Titanium dioxide, iron oxides, colorants
Processing aid	Talc

The tablet core must balance hardness against rapid breakup after the enteric coat dissolves. Excessive compression can delay disintegration and create dissolution variability. Excessive disintegrant can weaken the tablet or increase friability.

Enteric-coating excipients

The delayed-release layer generally uses:

• Methacrylic acid copolymer
• Talc
• Titanium dioxide
• Plasticizer, such as triethyl citrate
• Water or hydroalcoholic processing solvent, depending on the coating system

Methacrylic acid copolymers are selected according to target dissolution pH. The polymer grade affects the point at which the coating dissolves, coating weight, film strength, and sensitivity to storage conditions.

Excipient attributes with commercial significance

For a generic or reformulated Asacol product, the most important excipient attributes are:

• Polymer dissolution threshold
• Plasticizer compatibility
• Coating permeability
• Coating weight gain
• Moisture sensitivity
• Tablet porosity
• Mechanical strength
• Residual solvent profile
• Colorant and titanium dioxide requirements
• Lactose content
• Phthalate status
• Microbial and elemental impurity controls

The excipient list alone does not establish pharmaceutical equivalence. FDA review focuses on comparative dissolution, stability, dose strength, manufacturing controls, and the applicable ANDA requirements.

What excipient strategy best supports an Asacol generic?

The highest-value strategy is to preserve the established release profile while reducing formulation and manufacturing complexity.

1. Use a robust pH-dependent polymer system

A methacrylic acid copolymer remains the lowest-risk platform because it is widely understood by regulators and contract manufacturers. The commercial opportunity is to optimize polymer grade and coating weight rather than introduce an unproven delivery technology.

Potential advantages include:

• Lower coating weight
• Faster coating throughput
• Reduced aqueous coating time
• Lower tablet weight
• More consistent dissolution
• Reduced batch-to-batch variation

The formulation must demonstrate adequate resistance in acidic media and reproducible release at the target intestinal pH.

2. Develop phthalate-free coatings

Phthalate-free excipient systems can support a differentiated product position. Triethyl citrate, acetyl tributyl citrate, and other accepted plasticizers may replace older plasticizer systems, subject to formulation performance and regulatory review.

A phthalate-free claim can support:

• Pediatric and caregiver positioning
• Hospital formulary acceptance
• International registration
• Institutional procurement
• Reformulation lifecycle management

The claim must be supported by the complete composition and supplier documentation. A formulation cannot be characterized as phthalate-free if phthalate-containing processing aids, colorants, or packaging components introduce measurable residues.

3. Reduce excipient and supplier complexity

A generic manufacturer can improve margin by reducing the number of excipients and qualifying dual suppliers for critical materials. The main targets are:

• Coating polymer
• Plasticizer
• Talc
• Lubricant
• Disintegrant
• Colorant
• Film-coating premix

The benefit is lower supply-chain risk and improved negotiating leverage. The regulatory cost is comparability work whenever a change affects dissolution, stability, coating performance, or impurity profiles.

4. Optimize tablet dimensions

Asacol tablets are swallowed several times per day in some dosing regimens. Tablet size directly affects adherence. A smaller tablet can create a commercial advantage, but only if it preserves the required dose, coating coverage, mechanical properties, and dissolution behavior.

This creates a formulation opportunity for:

• Higher drug loading
• Lower core excipient burden
• More efficient compression
• Reduced tablet volume
• Alternative capsule or granule presentations

Size reduction is technically difficult because mesalamine has a high dose burden relative to many oral drugs.

What patents protect Asacol and its delivery system?

Asacol's historical protection relied on formulation and delayed-release technology rather than composition-of-matter exclusivity for mesalamine. The active ingredient has been known for decades, leaving limited opportunity for a modern patent on mesalamine itself.

Historical patent categories

The relevant patent categories include:

Patent category	Protected subject matter
Enteric-coated mesalamine	pH-dependent release in the distal intestine and colon
Tablet composition	Core excipient combinations and coating systems
Manufacturing process	Compression, coating, curing, and stability controls
Dosage regimen	Administration for ulcerative colitis
High-strength formulation	Asacol HD tablet strength and dosing
Product-by-process claims	Manufacturing conditions linked to product characteristics

Historical Asacol patent disputes involved delayed-release mesalamine formulations and later high-strength products. The practical commercial effect of these patents has diminished as the principal products moved beyond their original exclusivity periods and generic products entered the market.

The relevant patent analysis must distinguish between:

• Expired historical patents
• Patents listed for specific NDAs
• Patents covering a particular dosage form
• Unlisted formulation know-how
• Manufacturing trade secrets
• Patents for successor products such as Delzicol or Asacol HD

A patent covering an enteric-coated mesalamine tablet does not automatically block a capsule, granule, suppository, enema, or a product using a materially different coating system.

When did Asacol lose exclusivity?

Asacol's primary commercial exclusivity ended before the current generic market matured. FDA records identify Asacol as a legacy mesalamine product, while Asacol HD and Delzicol were developed as separate products with different product presentations and regulatory histories.

The principal exclusivity events are:

Event	Commercial effect
Original Asacol approval	Established delayed-release mesalamine tablet platform
Expiration of early formulation patents	Opened the route for generic development
Generic mesalamine delayed-release approvals	Created price competition
Asacol HD launch	Shifted dosing toward a higher-strength tablet
Delzicol approval	Introduced a successor delayed-release capsule presentation
Brand discontinuation or reduced availability	Increased dependence on generic supply

The exact Orange Book status depends on the NDA, strength, dosage form, and product presentation. A discontinued brand product may remain listed in FDA databases without being commercially available. Discontinued status does not itself determine whether a patent is enforceable.

What is the Orange Book status of Asacol?

The Orange Book is product-specific. Asacol, Asacol HD, and Delzicol must be evaluated by NDA number, strength, dosage form, and applicant.

FDA Orange Book review should address:

• Whether the reference listed drug remains active
• Whether the product is identified as discontinued
• Whether patents are listed for the applicable NDA
• Whether a 30-month stay was triggered by a Paragraph IV certification
• Whether exclusivity has expired
• Whether an ANDA references the specific product

Generic mesalamine products may reference different listed drugs depending on their strength and formulation. A generic applicant cannot assume that approval of one mesalamine delayed-release product establishes substitutability for every Asacol presentation.

Which companies are challenging or competing with Asacol?

Competition comes from generic manufacturers and branded mesalamine products rather than from biosimilars.

Generic manufacturers

The main competitive group includes manufacturers of mesalamine delayed-release tablets and capsules. Depending on the dosage form and market, the relevant companies may include:

• Teva Pharmaceutical Industries
• Zydus Pharmaceuticals
• Dr. Reddy's Laboratories
• Amneal Pharmaceuticals
• Sun Pharmaceutical Industries
• Lupin
• Sandoz
• Other regional ANDA holders and contract manufacturers

The relevant commercial question is not simply whether a company has FDA approval. Market access depends on manufacturing capacity, backorder history, wholesaler contracts, reimbursement status, and ability to supply multiple strengths.

Branded and alternative mesalamine products

The competitive set includes:

• Delzicol delayed-release capsules
• Asacol HD tablets
• Lialda extended-release tablets
• Apriso extended-release capsules
• Pentasa controlled-release capsules
• Rowasa rectal suspension
• Canasa suppositories
• Generic mesalamine tablets, capsules, enemas, and suppositories

These products compete through delivery location, dosing frequency, tablet or capsule burden, payer status, and physician familiarity.

What generic entry risks exist for Asacol?

Generic entry risk is high for the legacy Asacol platform because mesalamine is an established molecule and the central delayed-release technology uses mature excipient chemistry.

The main barriers are technical rather than fundamental patent barriers:

1. Achieving equivalent dissolution across pH stages.
2. Controlling coating thickness at commercial scale.
3. Matching stability under humidity and temperature stress.
4. Demonstrating bioequivalence through the applicable FDA pathway.
5. Securing reliable enteric-polymer supply.
6. Avoiding tablet cracking, premature release, and delayed release.
7. Establishing a commercially viable cost of goods.

A Paragraph IV challenge can create litigation exposure where listed patents remain active. The principal risk is product-specific. A patent dispute over Asacol HD does not necessarily block a conventional Asacol tablet or a Delzicol capsule.

What formulation patents and manufacturing IP remain commercially valuable?

Even after core patents expire, formulation and manufacturing IP can retain value through know-how and process control.

High-value technical IP

The strongest areas for new patent filings include:

• Low-coating-weight enteric tablets
• Phthalate-free coatings
• Moisture-resistant formulations
• High-drug-load cores
• Smaller tablets
• Multi-unit pellet or granule systems
• Reduced-frequency dosing
• Modified release with improved colonic targeting
• Stable formulations using alternative plasticizers
• Continuous coating and curing processes
• Formulations with reduced tablet-to-tablet dissolution variability

Patent strength is higher when claims combine composition and measurable performance characteristics. Broad claims to "an enteric-coated mesalamine tablet" face substantial prior-art pressure. Narrow claims tied to polymer ratios, coating weight, dissolution limits, stability results, or manufacturing parameters are more defensible but may be easier to design around.

What commercial opportunities exist in Asacol excipients?

The strongest opportunities are in value-added formulation services and excipient platforms rather than in the basic supply of commodity materials.

Opportunity matrix

Opportunity	Commercial rationale	Development risk
Phthalate-free coating system	Differentiated safety and procurement profile	Moderate
Smaller high-load tablet	Improved swallowing and adherence	High
Dual-source coating platform	Supply security and lower cost	Low to moderate
Ready-to-use coating premix	Faster scale-up and reduced manufacturing complexity	Moderate
Pediatric granules or sachets	New administration format	High
Colon-targeted multiparticulates	Product differentiation	High
Contract formulation and tech transfer	Supports regional generic launches	Moderate
Excipient substitution package	Enables lifecycle and supply-chain changes	Moderate

The most practical near-term opportunity is a validated ready-to-use coating system for mesalamine delayed-release tablets. Such a system can combine polymer, plasticizer, pigment, and anti-tacking components, supported by dissolution data and scale-up instructions.

A second opportunity is an excipient substitution package that allows manufacturers to move away from a single supplier without changing the finished-product release profile. This has value during shortages and regulatory changes.

How does Asacol compare with competing mesalamine products?

Product	Dosage form	Release strategy	Main commercial differentiator
Asacol	Delayed-release tablet	pH-dependent enteric release	Established colon-targeted tablet
Asacol HD	Higher-strength delayed-release tablet	pH-dependent delayed release	Lower tablet count
Delzicol	Delayed-release capsule	Encapsulated delayed-release dosage form	Successor presentation
Lialda	Extended-release tablet	MMX-based release technology	Once-daily dosing
Apriso	Extended-release capsule	Controlled release	Once-daily regimen
Pentasa	Controlled-release capsule	Ethylcellulose-based release	Broader intestinal release
Rowasa	Rectal suspension	Local rectal delivery	Distal disease
Canasa	Rectal suppository	Local rectal delivery	Rectal ulcerative colitis

Asacol's excipient opportunity is strongest where a manufacturer wants a lower-cost, reliable delayed-release tablet. Lialda and Apriso compete more directly on dosing frequency and branded positioning, while rectal products compete on disease location.

What is the regulatory status of mesalamine generics?

FDA approval generally proceeds through the ANDA pathway when the applicant can demonstrate equivalence to the relevant reference product. The product must meet requirements for identity, strength, quality, purity, stability, dissolution, and bioequivalence.

For delayed-release mesalamine, dissolution testing is central. The formulation must resist release in acid and release the active ingredient under the specified intestinal pH conditions. Changes to coating polymer, plasticizer, coating weight, tablet core, or manufacturing process can affect ANDA comparability.

Mesalamine is a small molecule, so biosimilar risk is not relevant. The competitive risk is generic substitution, branded reformulation, and alternative mesalamine delivery systems.

What geographic markets offer the best opportunity?

The United States has the most developed generic market and the clearest FDA reference-product framework. Europe, Canada, Latin America, and selected Asian markets offer opportunities where local competitors, pricing, and registration requirements differ.

A global excipient strategy should account for:

• Different permitted colorants
• Titanium dioxide restrictions
• Phthalate policies
• Local pharmacopoeial standards
• Country-specific bioequivalence requirements
• Tablet scoring and labeling rules
• Pediatric dosage expectations
• Import dependence for coating polymers
• Regional contract manufacturing capacity

A formulation designed for one jurisdiction may require excipient or coating changes elsewhere. Those changes can create separate regulatory work and potential patentable improvements.

Key Takeaways

• Asacol is a legacy mesalamine delayed-release tablet platform based on pH-dependent enteric delivery.
• The active ingredient is genericized; commercial differentiation depends on formulation and manufacturing.
• The core excipient strategy uses a mesalamine tablet core with a methacrylic acid copolymer coating, plasticizer, talc, pigments, and standard processing excipients.
• Phthalate-free coatings, smaller high-load tablets, ready-to-use coating systems, and dual-source excipient platforms offer the clearest commercial opportunities.
• Generic entry risk is high, but technical barriers remain in dissolution control, coating uniformity, stability, and scale-up.
• Orange Book and Paragraph IV analysis must be performed separately for Asacol, Asacol HD, Delzicol, and other mesalamine reference products.
• Biosimilar risk does not apply because mesalamine is a small-molecule drug.
• New patent value is most likely in narrow claims covering polymer ratios, coating weight, dissolution performance, stability, or manufacturing processes.

FAQs

Can a generic manufacturer replace Asacol's coating polymer?

Yes. A substitute polymer may be used if the finished product satisfies regulatory requirements for dissolution, stability, quality, and equivalence. The substitution may require comparative formulation and process data.

Are Asacol excipients suitable for pediatric formulations?

Some conventional excipients are suitable, but pediatric use requires a separate assessment of swallowability, tablet size, flavor, allergen content, and exposure to colorants, plasticizers, and other inactive ingredients.

Can a phthalate-free Asacol formulation obtain new patent protection?

Potentially. Patentability depends on novelty, non-obviousness, claim scope, and demonstrated technical effect. A simple substitution of one known plasticizer for another may face obviousness challenges.

Does Asacol require a biologic-style biosimilar pathway?

No. Mesalamine is a synthetic small molecule. Generic products generally use the ANDA pathway, subject to the applicable reference-product and bioequivalence requirements.

What is the most attractive contract-manufacturing opportunity for Asacol?

A validated delayed-release tablet platform with ready-to-use enteric coating, multiple dose strengths, dual-sourced excipients, and established dissolution performance offers the most scalable opportunity.

References

1. U.S. Food and Drug Administration. (n.d.). Asacol and Asacol HD prescribing information. FDA Drugs@FDA.

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

3. U.S. Food and Drug Administration. (2013). Guidance for industry: Bioequivalence studies with pharmacokinetic endpoints for drugs submitted under an ANDA. FDA.

4. U.S. Food and Drug Administration. (2016). Inactive ingredient database. FDA.

5. U.S. Food and Drug Administration. (n.d.). Delzicol prescribing information. FDA Drugs@FDA.

6. U.S. Food and Drug Administration. (n.d.). Lialda, Apriso, Pentasa, Rowasa, and Canasa prescribing information. FDA Drugs@FDA.

7. United States Pharmacopeia. (2024). United States Pharmacopeia and National Formulary. USP Convention.