List of Excipients in Branded Drug RAYOS

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Horizon Therapeutics USA Inc	RAYOS	prednisone	75987-020	CROSCARMELLOSE SODIUM
Horizon Therapeutics USA Inc	RAYOS	prednisone	75987-020	DIBASIC CALCIUM PHOSPHATE DIHYDRATE
Horizon Therapeutics USA Inc	RAYOS	prednisone	75987-020	FERRIC OXIDE RED
Horizon Therapeutics USA Inc	RAYOS	prednisone	75987-020	FERRIC OXIDE YELLOW
Horizon Therapeutics USA Inc	RAYOS	prednisone	75987-020	GLYCERYL DIBEHENATE

RAYOS Excipient Strategy and Commercial Opportunities in Delayed-Release Prednisone

Last updated: October 5, 2026

RAYOS is a delayed-release prednisone tablet approved by the FDA in 2012. Its commercial differentiation depends primarily on the dosage form and release timing, not on prednisone itself. The strongest excipient opportunities are reformulations that preserve the delayed-release pharmacokinetic profile while improving swallowability, excipient tolerability, dose flexibility, adherence, or manufacturing cost.

Because RAYOS is a small-molecule product, it has no biosimilar exposure. Its competitive risks come from immediate-release prednisone generics, delayed-release generic or 505(b)(2) products, patent challenges, and reformulations that replicate the release profile with a lower-cost excipient system.

What is RAYOS and how does its formulation work?

RAYOS contains prednisone in 1 mg, 2 mg, and 5 mg delayed-release tablets. The product is designed for bedtime administration, with prednisone release delayed until several hours after dosing. The intended clinical effect is morning exposure aligned with inflammatory symptoms, particularly in rheumatoid arthritis and other corticosteroid-responsive conditions [1].

Attribute	RAYOS profile
Active ingredient	Prednisone
Dosage form	Delayed-release tablet
Strengths	1 mg, 2 mg, 5 mg
FDA application	NDA 202533
Initial FDA approval	July 2012
Primary commercial differentiator	Delayed release and bedtime dosing
Reference product company	Horizon Pharma; acquired by Amgen in 2023
Generic category	Small-molecule drug; no biosimilar pathway
Core competitive products	Immediate-release prednisone tablets and potential delayed-release equivalents

RAYOS uses a proprietary tablet architecture rather than a new prednisone molecule. The formulation creates a lag before release in the gastrointestinal tract. That lag is the central technical barrier and the main source of value in the product.

What excipients are used in RAYOS?

The RAYOS label identifies conventional tablet excipients, including lactose monohydrate, crospovidone, povidone, sucrose, corn starch, magnesium stearate, and colloidal silicon dioxide. The dosage form also uses coating materials associated with film coating and delayed release, including hypromellose, polyethylene glycol, talc, and titanium dioxide, according to product labeling and regulatory product information [1, 2].

The excipients have different functional roles:

Excipient class	Representative materials	Primary function
Diluent	Lactose monohydrate, sucrose, starch	Tablet mass and dose uniformity
Binder	Povidone	Granule and tablet strength
Disintegrant	Crospovidone	Core breakup after release
Glidant	Colloidal silicon dioxide	Powder flow
Lubricant	Magnesium stearate	Compression and ejection
Coating polymer	Hypromellose and related film-forming materials	Protective and functional coating
Plasticizer	Polyethylene glycol	Film flexibility
Opacifier or pigment	Titanium dioxide, talc	Appearance and coating performance

The strategic point is that most of the listed materials are not individually defensible commercial assets. The value lies in their arrangement, coating thickness, polymer selection, processing conditions, and dissolution profile.

What excipient strategy protects the commercial value of RAYOS?

The most defensible excipient strategy is a functional formulation strategy. It should connect each excipient and process parameter to a measurable release attribute.

1. Preserve the delayed-release lag time

A substitute formulation must reproduce the intended delay before prednisone release. Critical variables include:

• Enteric polymer chemistry
• Polymer weight gain
• Coating uniformity
• Plasticizer concentration
• Pore-former concentration
• Core porosity
• Tablet hardness
• Compression force
• Coating curing conditions
• Dissolution behavior across gastric and intestinal pH

A generic product can use different excipients if it demonstrates pharmaceutical equivalence and bioequivalence. The reference sponsor therefore has greater protection when claims cover the functional combination of excipients, coating layers, processing ranges, and dissolution limits rather than naming only common materials.

2. Reduce dependence on lactose and sucrose

Lactose and sucrose create potential commercial segmentation opportunities. A lactose-free or reduced-sugar version could target patients with lactose intolerance, excipient sensitivity, diabetes-related concerns, or preference for lower-sugar products.

The commercial value is likely greater in chronic-use markets than in short-course steroid treatment. RAYOS is used in conditions requiring repeated or long-term corticosteroid therapy, making tolerability and patient preference more relevant than they would be for acute dosing.

A lactose-free replacement could use mannitol, microcrystalline cellulose, dibasic calcium phosphate, or directly compressible starch. Each alternative would require optimization because changes in density, hygroscopicity, hardness, and disintegration can alter the delayed-release profile.

3. Improve dose flexibility

RAYOS is available in three strengths, but chronic prednisone therapy often requires individualized tapering. Commercial opportunities include:

• Lower-dose tablets below 1 mg
• Scored tablets where technically feasible
• Combination packaging for taper schedules
• Dose packs aligned with physician-directed regimens
• Multiparticulate or sprinkle presentations
• Improved tablet identification by strength

A scored delayed-release tablet is technically difficult. Splitting can disrupt the coating and create premature release. A commercial dose-flexibility strategy therefore should favor multiple low-strength units or unit-dose packaging rather than relying on tablet splitting.

4. Develop a lower-cost coating system

The delayed-release coating is likely the most important cost and manufacturing target. Opportunities include:

• Lower coating weight gain
• Aqueous rather than solvent-based coating
• More efficient pan-coating or fluid-bed processing
• Reduced curing time
• Lower-cost enteric polymers
• Reduced titanium dioxide or pigment content
• Fewer coating layers
• Improved batch-to-batch coating uniformity

A cost-reduced formulation must maintain dissolution performance under acidic and intestinal conditions. Small changes in coating permeability can produce clinically relevant changes in the lag time and exposure curve.

5. Address excipient risk in pediatric and geriatric populations

RAYOS is primarily a chronic-use product, and its patients may include older adults with dysphagia, polypharmacy, or dietary restrictions. A smaller tablet, orally dispersible presentation, or multiparticulate capsule could improve administration.

These products would not be simple line extensions. The delayed-release mechanism must remain intact during dispersion, swallowing, and gastrointestinal transit. Crushing or chewing would likely be unsuitable unless a redesigned dosage form protects the release-controlling layer.

What patents protect the RAYOS delayed-release formulation?

The principal patent risk is associated with the delayed-release prednisone dosage form and its release architecture. The relevant patent family has been associated with delayed-release pharmaceutical compositions and commercial development of the RAYOS product. One commonly cited U.S. patent is U.S. Patent No. 8,343,508, which covers delayed-release pharmaceutical compositions and has a nominal patent term extending into the late 2020s based on its priority and filing history [3].

Patent scope should be separated into four categories:

Patent category	Relevance to RAYOS
Composition patents	Excipients, active ingredient, and functional formulation
Coating patents	Polymer layers, coating weight, and release control
Method-of-use patents	Bedtime dosing or treatment aligned with circadian symptoms
Process patents	Granulation, compression, coating, curing, and manufacturing controls

A formulation competitor can avoid a narrow composition claim by changing the polymer system or using a different dosage-form architecture. That does not eliminate infringement risk if broader functional or process claims remain enforceable.

The commercial importance of any RAYOS patent depends on the current Orange Book listing, patent-term adjustment, pediatric exclusivity, terminal disclaimers, reexamination or post-grant proceedings, and litigation outcomes. Patent expiration should not be treated as a single date without separating composition, method-of-use, and regulatory exclusivity rights.

When does RAYOS lose exclusivity?

RAYOS lost new chemical entity exclusivity years after its 2012 approval because prednisone was already an established active ingredient. Its regulatory protection has therefore depended mainly on the approved formulation, listed patents, and any applicable three-year clinical investigation exclusivity.

The practical exclusivity timeline is:

Event	Timing
FDA approval of RAYOS	2012
NCE exclusivity	Not available for prednisone
Formulation-related regulatory protection	Potentially applicable depending on FDA classification
Patent protection	Extends beyond approval for listed delayed-release technology
Generic entry	Dependent on patent challenges, court outcomes, and FDA approval

The major business question is not whether immediate-release prednisone is generic. It is whether a competing product can lawfully and economically reproduce RAYOS's delayed-release profile.

What is the Orange Book status of RAYOS?

RAYOS is an FDA-approved prescription product listed in FDA drug databases under prednisone delayed-release tablets and NDA 202533 [1, 4]. The Orange Book is the controlling source for current patent listings and therapeutic-equivalence information.

For competitive diligence, the relevant Orange Book questions are:

1. Which patents are currently listed against NDA 202533?
2. Are the listed patents composition, method-of-use, or formulation patents?
3. Have any listings been delisted, expired, or withdrawn?
4. Has FDA accepted an ANDA with a Paragraph IV certification?
5. Is a generic delayed-release prednisone product therapeutically equivalent to RAYOS or merely pharmaceutically related?
6. Does a proposed 505(b)(2) product rely on RAYOS clinical data while using a different release system?

Immediate-release prednisone products should not be assumed to be substitutable for RAYOS. Therapeutic substitution depends on the release profile, labeling, and FDA equivalence determination.

Which companies are challenging RAYOS?

Publicly visible competitive pressure has historically come from manufacturers of immediate-release prednisone tablets rather than from a large established group of delayed-release competitors. Common prednisone suppliers include generic manufacturers such as Teva, Hikma, Amneal, Viatris, and other ANDA holders, although their immediate-release products do not necessarily replicate RAYOS.

A direct RAYOS challenge would most likely come from:

• An ANDA sponsor filing a Paragraph IV certification
• A 505(b)(2) sponsor developing a delayed-release prednisone product
• A contract development and manufacturing organization offering a coating platform
• A generic manufacturer using an alternative enteric polymer system
• A specialty pharmaceutical company pursuing a lower-cost chronic steroid product

No biosimilar challenge applies because prednisone is a chemically synthesized small molecule.

What Paragraph IV risks exist for RAYOS?

A Paragraph IV challenge could target one or more listed patents while asserting that the patent is invalid, unenforceable, or not infringed. The most likely technical positions would involve:

• A different enteric polymer
• A different coating thickness
• A different tablet core
• A distinct dissolution profile that still meets bioequivalence requirements
• A multiparticulate or capsule-based dosage form
• A non-infringing manufacturing process

The sponsor's litigation position would depend on whether the claims require a specific excipient, a defined release lag, a coating sequence, or broader functional language.

A first-filer could obtain 180-day generic exclusivity if it meets statutory requirements. The commercial impact would be greater for a delayed-release generic than for immediate-release prednisone because the direct substitution opportunity would be stronger.

What commercial opportunities exist for RAYOS excipients?

The best opportunities are not commodity excipient sales. They are platform products tied to clinical and regulatory outcomes.

Excipient suppliers

Excipient companies can pursue:

• High-performance enteric polymers
• Low-viscosity coating systems
• Ready-to-use coating premixes
• Low-moisture excipient grades
• Lactose-free direct-compression systems
• Functional excipients that improve coating adhesion
• Plasticizer systems that reduce cracking and curing time
• Color-free or titanium-dioxide-free coating systems

The strongest sales proposition is a validated excipient system that reduces development time and improves dissolution robustness.

Contract manufacturers

CMOs can offer:

• Delayed-release tablet development
• Scale-up of functional coating processes
• Comparative dissolution testing
• Stability programs
• Pilot bioequivalence batches
• Manufacturing-process intellectual property
• ANDA or 505(b)(2) development support

Coating capability is the main operational differentiator. Many manufacturers can compress prednisone tablets; fewer can consistently produce a delayed-release product with a reproducible lag time at commercial scale.

Specialty pharmaceutical companies

A reformulated prednisone product could target:

• Lactose-free chronic corticosteroid therapy
• Lower-cost delayed-release prednisone
• Pediatric dosing
• Dysphagia and geriatric use
• Unit-dose taper packaging
• Lower-dose maintenance therapy
• Markets outside the United States where RAYOS access is limited

The regulatory pathway would depend on the degree of similarity to RAYOS. A product using the same active ingredient but a modified release profile may require a 505(b)(2) application rather than a conventional ANDA.

How strong is the RAYOS patent estate?

The estate is strongest where it protects the delayed-release architecture and the relationship between formulation variables and pharmacokinetic performance. It is weaker against products that use a different dosage form, a different coating platform, or a non-overlapping process.

Estate element	Relative strength
Prednisone active ingredient	Low; long generic history
Conventional tablet excipients	Low
Delayed-release coating architecture	Moderate to high
Specific excipient combinations	Moderate, claim-dependent
Bedtime or circadian method of use	Variable
Manufacturing process	Moderate if process claims are narrow and well documented
Brand and product recognition	Moderate
Clinical differentiation versus immediate-release prednisone	Moderate

The commercial moat is therefore a combination of formulation know-how, regulatory data, physician familiarity, and manufacturing control. The active ingredient itself provides little protection.

What generic launch scenarios exist?

Three launch scenarios are commercially plausible:

1. Immediate-release substitution pressure: Generic prednisone remains a lower-cost alternative, but it does not fully replicate RAYOS's delayed-release timing.
2. Delayed-release ANDA entry: A sponsor obtains FDA approval and demonstrates therapeutic equivalence, creating direct price competition.
3. 505(b)(2) reformulation: A company launches a modified delayed-release, low-dose, or patient-friendly version with a differentiated label and potentially separate patent estate.

The highest-value opportunity for a challenger is a direct delayed-release equivalent. The lowest-risk development path may be an improved formulation that targets a specific patient segment but accepts a more complex regulatory route.

Key Takeaways

• RAYOS is a delayed-release prednisone tablet whose value comes from release timing, not molecular novelty.
• The main excipient opportunity is a functional coating and core system that preserves the delayed-release lag time.
• Lactose-free, sugar-reduced, lower-dose, dysphagia-friendly, and unit-dose products are commercially differentiated opportunities.
• Immediate-release prednisone generics create price pressure but are not automatically substitutable for RAYOS.
• The relevant patent risks concern delayed-release architecture, coating systems, formulation combinations, and manufacturing processes.
• RAYOS has no biosimilar risk because prednisone is a small molecule.
• A direct delayed-release generic would create the greatest revenue risk; a 505(b)(2) reformulation could create the greatest product-development opportunity.
• Excipient suppliers with validated enteric-coating systems and CMOs with commercial-scale coating expertise are best positioned to capture value.

FAQs About RAYOS Excipient and Patent Opportunities

Can lactose-free excipients be used to develop a RAYOS alternative?

Yes. Lactose can be replaced with materials such as mannitol, microcrystalline cellulose, dibasic calcium phosphate, or starch-based diluents. The replacement must be evaluated for tablet hardness, disintegration, coating adhesion, dissolution, stability, and bioequivalence.

Is RAYOS protected by prednisone patents?

Prednisone itself is not protected by modern composition-of-matter exclusivity. Protection focuses on the delayed-release formulation, coating architecture, methods of use, and manufacturing technology.

Can an immediate-release prednisone generic replace RAYOS?

Not automatically. Immediate-release prednisone has a different release profile and may not reproduce the bedtime-to-morning exposure pattern associated with RAYOS.

Would a sprinkle formulation of RAYOS require a new FDA application?

Likely yes. A sprinkle or multiparticulate product that changes the dosage form or administration method would generally require regulatory support beyond a simple excipient substitution, with the pathway depending on its similarity to the reference product.

Which excipient has the greatest strategic value in a RAYOS competitor?

The delayed-release polymer and its coating system have the greatest strategic value. Common fillers, binders, lubricants, and disintegrants are easier to substitute and offer less patent differentiation.

References

1. U.S. Food and Drug Administration. (2012). RAYOS (prednisone) delayed-release tablets, prescribing information.
2. National Library of Medicine. (n.d.). DailyMed: RAYOS prednisone delayed-release tablets.
3. U.S. Patent and Trademark Office. (2013). U.S. Patent No. 8,343,508, pharmaceutical composition for delayed release of an active ingredient.
4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.