List of Excipients in Branded Drug CHOLESTYRAMINE

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Generic Drugs Containing CHOLESTYRAMINE

Company	Ingredient	NDC	Excipient
Eon Labs Inc	cholestyramine	0185-0940	AMMONIUM GLYCYRRHIZATE
Eon Labs Inc	cholestyramine	0185-0940	ANHYDROUS CITRIC ACID
Eon Labs Inc	cholestyramine	0185-0940	D&C YELLOW NO. 10
Eon Labs Inc	cholestyramine	0185-0940	FD&C YELLOW NO. 6
Eon Labs Inc	cholestyramine	0185-0940	FRUCTOSE
Eon Labs Inc	cholestyramine	0185-0940	ORANGE

What are the Most Frequently-Used Excipients in CHOLESTYRAMINE?

# Of NDCs	Excipient
9	ACACIA
1	ALUMINUM OXIDE
7	AMMONIUM GLYCYRRHIZATE
28	ANHYDROUS CITRIC ACID
8	ASPARTAME
1	CITRIC ACID ANHYDROUS

Cholestyramine Excipient Strategy, Formulation Patents, and Commercial Opportunities

Last updated: October 16, 2026

Cholestyramine is an established, patent-expired bile acid sequestrant with limited active-ingredient exclusivity and substantial formulation friction. The strongest commercial opportunities are in taste masking, dose convenience, sugar-free and low-calorie formats, pediatric administration, drug-binding warnings, and improved suspension performance. The main barriers are poor palatability, large dose volume, variable dispersion, gastrointestinal tolerability, and the resin’s ability to bind co-administered medicines.

What is the regulatory and commercial status of cholestyramine?

Cholestyramine is an FDA-approved oral anion-exchange resin used to reduce LDL cholesterol and to treat pruritus associated with partial biliary obstruction. The drug is supplied primarily as a powder that is mixed with liquid before administration.

Attribute	Status
Active ingredient	Cholestyramine resin
Drug class	Bile acid sequestrant
Primary dosage form	Oral powder for suspension
Original U.S. approval	1973
Reference product	Questran
Other marketed products	Questran Light, Prevalite, generic cholestyramine powders
FDA pathway for generics	ANDA, subject to product-specific requirements
Current NCE exclusivity	None
Current meaningful active-ingredient patent protection	None identified
Biosimilar exposure	Not applicable
Main commercial constraint	Administration burden and palatability

The reference product, Questran, was originally approved under NDA 016656. Current products compete mainly through price, availability, flavor, packaging, and patient acceptability rather than through active-ingredient differentiation. FDA labeling identifies cholestyramine as a powder that must be mixed with fluid or a pulpy food before administration. The label also warns that the resin can bind other drugs and reduce their absorption.[1]

When does cholestyramine lose exclusivity?

Cholestyramine lost practical market exclusivity decades ago. Its original composition and product patents are outside their enforceable terms, and the molecule does not have current FDA marketing exclusivity.

FDA exclusivity timeline

Event	Approximate timing
Original U.S. approval of Questran	1973
Original product exclusivity period	Expired
Original composition and process patent terms	Expired
Generic availability	Established for many years
Current NCE exclusivity	None
Current orphan exclusivity	None
Current pediatric exclusivity	None identified
Current Orange Book patent barrier	No unexpired barrier identified

A new cholestyramine product could potentially obtain limited regulatory exclusivity if it qualifies for a new clinical indication, a new formulation requiring substantial clinical investigation, or another qualifying FDA pathway. That protection would attach to the approved innovation, not to cholestyramine as an active ingredient.

A reformulated product is more likely to be pursued through an ANDA, 505(b)(2) application, or a conventional supplement, depending on the extent of formulation and clinical changes. A 505(b)(2) strategy may be relevant for a materially different dosage form, delivery system, or administration method, but it would require a defensible bridge to the existing safety and efficacy record.

What patents protect cholestyramine products?

No unexpired patent estate is currently known to provide broad protection for cholestyramine resin as an active pharmaceutical ingredient. The commercial opportunity is therefore based on formulation execution, regulatory positioning, manufacturing know-how, and brand differentiation.

Composition and process patents

Historical cholestyramine patents covered resin composition, preparation, crosslinking, particle characteristics, and use as a bile acid sequestrant. Those patent terms have expired. New patents could still be pursued for:

• A defined resin particle-size distribution
• Controlled swelling or hydration properties
• Improved suspension stability
• Taste-masking systems
• Low-dust granules
• Unit-dose delivery systems
• A chewable or dispersible dosage form
• A specific excipient ratio that improves redispersion
• A manufacturing process that reduces batch variability
• A combination product with a separately protected active ingredient

The commercial value of these claims depends on whether competitors can design around the excipient system or manufacturing process. A patent that claims only a broad combination of cholestyramine, sweetener, and flavoring would likely face validity and enablement pressure. Narrower claims tied to measurable performance, such as dispersion time, sedimentation behavior, particle size, or palatability scores, would be more defensible if supported by robust comparative data.

Orange Book status

The relevant commercial question is whether an ANDA applicant would face listed patent certifications. Cholestyramine products do not have a current, high-value Orange Book patent barrier comparable to newer small-molecule products. Generic applicants therefore are unlikely to face a meaningful Paragraph IV campaign against foundational cholestyramine patents.

What excipients are used in cholestyramine formulations?

Cholestyramine products use excipients to solve five technical problems: taste, odor, mouthfeel, powder flow, and suspension behavior. The resin itself is bulky, insoluble, and capable of producing a gritty or pasty oral experience.

Core excipient categories

Formulation function	Potential excipient classes	Strategic objective
Sweetening	Sucrose, sucralose, aspartame, acesulfame potassium, polyols	Reduce resin bitterness and improve adherence
Flavoring	Citrus, fruit, vanilla, mint, berry systems	Mask resin taste and odor
Acidification	Citric acid, malic acid, fumaric acid	Improve flavor profile and perceived freshness
Wetting and dispersion	Polysorbates, low-level surfactants, hydrophilic carriers	Improve wetting and reduce floating or clumping
Suspending	Acacia, cellulose derivatives, xanthan gum, other hydrocolloids	Maintain uniformity after reconstitution
Anti-caking and flow	Colloidal silicon dioxide and similar agents	Improve powder handling and sachet filling
Bulking	Sugars, polyols, maltodextrin, soluble fibers	Improve dose volume and powder uniformity
Color	Approved color additives	Support flavor recognition and product differentiation
Buffering	Citrate or phosphate systems	Control pH and improve sensory performance

The excipient selection must account for the resin’s ion-exchange behavior. Highly ionic excipients, strongly adsorptive materials, and certain polymers may alter hydration, swelling, dispersion, or binding performance. Formulators must also evaluate whether the excipient system increases binding of concomitant medicines.

Sugar-free and low-calorie systems

Sugar-free products offer a clear commercial opportunity because cholestyramine is used by patients with metabolic disease, including diabetes and obesity. Polyols can improve mouthfeel but may cause gastrointestinal discomfort at high levels. High-intensity sweeteners reduce caloric contribution but can introduce aftertaste or regulatory labeling requirements.

Aspartame-containing products require phenylalanine labeling. Products using sucrose face positioning limits for patients monitoring carbohydrate intake. A low-sugar product with a citrus or berry flavor and a compact unit-dose sachet could compete on usability rather than price.

Pediatric excipient strategy

Cholestyramine is not a naturally convenient pediatric product. A pediatric formulation would need:

• A reliable dose-measuring system
• Lower dust generation
• Improved wetting in small liquid volumes
• A flavor acceptable to children
• Clear instructions for mixing with soft food
• Compatibility with feeding schedules and other medicines
• Safety review of sweeteners, colorants, and preservatives

The resin’s drug-binding behavior is especially important in children receiving multiple therapies. A pediatric product should provide prominent administration separation instructions and avoid excipients that complicate interpretation of absorption or tolerability.

What formulations are protected by cholestyramine patents?

No broad, currently enforceable cholestyramine formulation patent category dominates the market. The most defensible future formulation claims would protect performance characteristics rather than ordinary flavor combinations.

High-value formulation concepts

Unit-dose granules

Granules can reduce dust, improve dosing accuracy, and make the product easier to pour into water or food. A granulated product may support claims covering particle size, granulation binder, porosity, wetting time, and redispersion.

Taste-masked powder

Taste masking is commercially important because cholestyramine has a resinous mouthfeel and can be difficult to swallow. A protected system could combine a coating, flavor matrix, sweetener, and controlled release of the resin into the liquid phase.

Rapid-dispersing sachet

A rapidly dispersing sachet would target patients who avoid the product because of clumping or prolonged mixing. Patent claims could focus on dispersion time, residual agglomerate size, sedimentation rate, and stability after reconstitution.

Sprinkle formulation

A sprinkle product designed for yogurt, applesauce, pudding, or other soft foods could improve adherence. The product must avoid excessive grittiness and must maintain a uniform dose in the food vehicle.

Chewable or compressed format

A chewable tablet, wafer, or lozenge could reduce preparation burden. The technical problem is dose loading. Standard treatment doses are sufficiently large that a practical chewable product could require multiple units or a high-density resin system.

How does cholestyramine compare with colesevelam and colestipol?

Cholestyramine competes with other bile acid sequestrants, especially colesevelam and colestipol. The main competitive distinction is administration convenience.

Product	Main dosage forms	Palatability and convenience	Key commercial position
Cholestyramine	Powder for suspension	Weakest convenience profile; mixing required	Low-cost established therapy
Colestipol	Granules and tablets	Better tablet option, but high pill burden can occur	Alternative bile acid sequestrant
Colesevelam	Tablets and oral suspension	More convenient, but higher cost	Premium convenience and tolerability position

Colesevelam has a more modern formulation profile and is available in tablet form, but cholestyramine retains a cost advantage and a long clinical history. A reformulated cholestyramine product does not need to outperform colesevelam on every attribute. It could target a narrower value proposition: lower cost than colesevelam, better palatability than legacy powders, and easier administration than standard cholestyramine.

What generic entry risks exist for cholestyramine?

Generic entry risk is high because the active ingredient and conventional powder dosage form are mature. A new branded product would face:

1. Price competition from established generic suppliers.
2. Easy substitution if the product is therapeutically equivalent.
3. Limited switching friction for payers.
4. Retail and wholesaler preference for low-cost suppliers.
5. Difficulty supporting a large premium without measurable adherence benefits.

A differentiated product could reduce direct substitution risk through a proprietary dosage form, branded packaging, better flavor, or a 505(b)(2) regulatory strategy. The protection would remain vulnerable if the product’s improvement is viewed as nonessential or if payers treat it as interchangeable with existing powder products.

Which companies are challenging or competing with cholestyramine?

The competitive set includes manufacturers of generic cholestyramine powders and branded or generic bile acid sequestrants. Questran and Questran Light established the reference-product market, while Prevalite and generic products expanded price competition.

The most relevant competitive products are:

• Generic cholestyramine powder for oral suspension
• Prevalite
• Questran and Questran Light
• Colestipol tablets and granules
• Colesevelam tablets and oral suspension

The market is fragmented and supplier-specific availability can change. A company seeking entry would need dependable resin sourcing, validated powder handling, compliant packaging, and stable distribution more than a large sales force.

What manufacturing and intellectual-property barriers affect cholestyramine?

Cholestyramine manufacturing is less dependent on conventional small-molecule synthesis and more dependent on polymer and resin control. Key barriers include:

• Consistent crosslinking and ion-exchange capacity
• Control of moisture and residual solvents
• Particle-size distribution
• Batch-to-batch swelling behavior
• Powder flow and fill-weight accuracy
• Flavor uniformity
• Low-dust processing
• Prevention of microbial contamination in flavored powders
• Stability of the excipient system
• Reliable supply of pharmaceutical-grade resin

The resin’s physical properties can materially affect patient experience and dose uniformity. Manufacturing know-how may therefore provide more practical protection than a broad composition patent. A company with a reproducible low-dust, rapidly dispersing, taste-masked granule could create a meaningful barrier even if competitors can legally formulate around the patent claims.

What patent litigation and settlement agreements affect cholestyramine?

No material current Paragraph IV litigation or settlement structure is associated with the foundational cholestyramine market. The principal patent disputes that would matter for a new entrant are more likely to involve a later-developed formulation, delivery device, or manufacturing process than cholestyramine itself.

A patent owner pursuing a differentiated formulation should monitor:

• ANDA filings with Paragraph IV certifications
• Declaratory-judgment actions
• Abbreviated New Drug Application product-specific requirements
• Orange Book listing eligibility
• State substitution practices
• Contract manufacturing and resin-supply agreements

Licensing opportunities are most plausible for a branded flavor system, proprietary granulation process, specialized resin, or delivery platform. A license covering only a conventional sweetener-flavor combination would have limited bargaining power.

What is the commercial opportunity for a new cholestyramine product?

The strongest opportunity is a differentiated oral product aimed at adherence and convenience rather than a new mechanism.

Attractive product concepts

Concept	Commercial rationale	Main risk
Sugar-free citrus sachet	Targets diabetes and calorie-conscious users	Sweetener aftertaste
Rapid-dispersing granules	Reduces clumping and preparation time	Higher manufacturing cost
Sprinkle product	Enables use with soft foods	Dose-uniformity concerns
Pediatric powder	Addresses administration and flavor barriers	Clinical and excipient complexity
Low-dust unit-dose format	Improves handling and portability	Packaging cost
Premium flavor platform	Supports brand differentiation	Weak reimbursement premium
Cholestyramine plus adherence packaging	Helps patients separate doses from other medicines	Limited patent breadth

Revenue exposure would depend on whether the product obtains a reimbursed brand position or remains a cash-pay convenience product. The likely ceiling is constrained by low-cost generic substitution and the availability of colesevelam and colestipol. A focused launch could still be viable if it achieves a measurable adherence benefit, secures favorable formulary placement, or addresses a segment underserved by current powders.

Key Takeaways

• Cholestyramine has no meaningful current active-ingredient exclusivity.
• The principal U.S. products are legacy powders requiring mixing before administration.
• The highest-value excipient work concerns taste masking, dispersion, mouthfeel, powder flow, and sugar-free positioning.
• Generic entry risk is high because the molecule and conventional dosage form are mature.
• Future patent value would come from measurable formulation performance and manufacturing controls.
• Colesevelam competes on convenience, while cholestyramine competes mainly on cost and clinical familiarity.
• A differentiated cholestyramine product should target adherence, pediatric use, low-dust delivery, or rapid dispersion.
• Biosimilar risk does not apply because cholestyramine is a nonbiologic small-molecule resin.
• Current commercial barriers are formulation quality, supply reliability, payer acceptance, and substitution economics rather than foundational patents.

FAQs

Can cholestyramine be reformulated as a tablet?

Yes, but the required dose creates a substantial tablet-size and pill-burden problem. A granule, wafer, chewable, or high-density multiparticulate system may be more practical than a conventional tablet.

Which excipients are most important for cholestyramine taste masking?

Sweeteners, fruit or citrus flavors, acidulants, and mouthfeel modifiers are the primary tools. The formulation must also preserve resin dispersion and avoid increasing drug-binding interactions.

Can a new cholestyramine product receive FDA exclusivity?

Potentially, but exclusivity would need to attach to a qualifying new formulation, indication, or clinical development program. Cholestyramine itself does not have new chemical entity exclusivity.

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

A materially different dosage form, administration method, or delivery system could support a 505(b)(2) strategy if the applicant can rely partly on existing findings and generate the studies required for the modification.

What is the most defensible patent strategy for cholestyramine?

Claims tied to measurable performance, such as rapid dispersion, controlled particle size, low dust, improved suspension stability, or a defined taste-masking architecture, are more defensible than broad claims covering ordinary flavors or sweeteners.

References

1. U.S. Food and Drug Administration. (n.d.). Questran and Questran Light prescribing information. FDA-approved labeling.

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

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

4. DailyMed. (n.d.). Cholestyramine powder for suspension prescribing information. National Library of Medicine.

5. U.S. Food and Drug Administration. (n.d.). Guidance for industry: Applications covered by section 505(b)(2). FDA.

6. U.S. Food and Drug Administration. (n.d.). Guidance for industry: ANDAs for certain highly purified synthetic drug substances. FDA.