List of Excipients in Branded Drug OPANA ER

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Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Rebel Distributors Corp	OPANA ER	oxymorphone hydrochloride	21695-948	CELLULOSE, MICROCRYSTALLINE
Rebel Distributors Corp	OPANA ER	oxymorphone hydrochloride	21695-948	FERRIC OXIDE RED
Rebel Distributors Corp	OPANA ER	oxymorphone hydrochloride	21695-948	FERROSOFERRIC OXIDE
Rebel Distributors Corp	OPANA ER	oxymorphone hydrochloride	21695-948	HYPROMELLOSES
Rebel Distributors Corp	OPANA ER	oxymorphone hydrochloride	21695-948	METHYLPARABEN

OPANA ER Excipient Strategy and Commercial Opportunities

Last updated: August 27, 2026

Opana ER was an extended-release oxymorphone hydrochloride tablet developed around matrix-based drug release and, later, abuse-deterrent performance. Its commercial lifecycle ended after FDA requested withdrawal in 2017 because postmarketing data indicated a serious risk of intravenous abuse. The principal commercial opportunity has shifted from selling oxymorphone ER to licensing excipient systems, abuse-deterrent manufacturing expertise, and controlled-release platform technology for other opioid and non-opioid products. [1][2]

What was Opana ER and how did its formulation work?

Opana ER contained oxymorphone hydrochloride, a potent opioid analgesic, in extended-release tablets administered every 12 hours. The formulation was designed to slow drug release through a hydrophilic matrix rather than through a simple immediate-release tablet.

The product had two commercially relevant formulation generations:

Formulation	Commercial role	Technical objective	Regulatory outcome
Original Opana ER	Initial extended-release product	Controlled oral release of oxymorphone	Approved in 2006
Reformulated Opana ER	Abuse-deterrent version	Make crushing and subsequent manipulation more difficult	Approved in 2011; withdrawn in 2017

The reformulated product used physical and mechanical properties intended to reduce crushing, powder formation and preparation for injection. The FDA classified it as having abuse-deterrent properties under the physical and chemical barrier category, but the agency did not find that it reduced abuse in the real-world setting sufficiently to justify continued marketing. [1][3]

Which excipients were used in Opana ER?

Public labeling identifies excipient classes used in the tablets, including matrix-forming polymers, binders, lubricants and colorants. The precise commercial formulation varied by strength and manufacturing version.

The principal formulation functions were:

Excipient function	Likely formulation role
Hydrophilic matrix polymer	Swelling and gel formation to control oxymorphone diffusion
High-molecular-weight polymer or polymer blend	Increased tablet hardness and resistance to crushing
Binder	Granule and tablet cohesion
Lubricant	Tablet ejection and manufacturing control
Glidant	Powder flow and blend uniformity
Opacifier or colorant	Tablet identification and dose differentiation
Coating system	Appearance, handling and possible mechanical protection

The reformulated product’s commercial differentiation did not depend only on the active ingredient. It depended on the combination of excipient selection, polymer molecular weight, tablet compression, granulation, coating, tooling and dissolution specifications. Those process variables can determine whether a tablet remains intact, forms a viscous mass after hydration or releases drug rapidly after mechanical manipulation.

What excipient strategy made the reformulated Opana ER commercially distinctive?

The strategy combined controlled release with physical abuse deterrence. The formulation had to satisfy competing performance requirements:

1. Release oxymorphone at a controlled rate during oral administration.
2. Maintain acceptable bioavailability and dose proportionality.
3. Resist crushing with commonly available tools.
4. Limit conversion into a snortable powder.
5. Reduce the ability to disperse the drug in water or other solvents.
6. Remain manufacturable at multiple tablet strengths.

A conventional hydrophilic matrix can provide extended release but may be vulnerable to crushing. An abuse-deterrent matrix therefore requires tighter control of polymer content, particle size, compression force, tablet hardness and hydration behavior.

The commercial value was in the integrated formulation process. A generic manufacturer could potentially match the listed ingredients yet fail to reproduce the reference product’s abuse-deterrent performance if its polymer grade, compression profile, granulation method or dissolution behavior differed.

What formulation attributes created intellectual-property value?

The most defensible IP positions in this type of product generally arise from:

• Specific polymer combinations and concentration ranges.
• Defined molecular-weight ranges for matrix-forming excipients.
• Resistance to crushing, pulverization or extraction.
• Drug-release profiles after intact and manipulated administration.
• Tablet hardness, friability and density.
• Manufacturing methods, including wet granulation and compression parameters.
• Coating or barrier layers.
• Formulations that produce a gel or viscous mass when exposed to aqueous media.
• Dose-specific compositions and release specifications.

The strongest protection usually combines composition claims with performance and manufacturing claims. A formulation patent limited to a broad class of hydrophilic polymers is easier to design around than a patent linked to measurable resistance and release characteristics.

What was the FDA regulatory status of Opana ER?

FDA approved Opana ER in 2006 under NDA 21-610. The agency approved the reformulated version in 2011 as an abuse-deterrent opioid product. FDA later requested withdrawal after concluding that the reformulated product’s benefits did not outweigh its risks because of continued abuse by injection and reports of thrombotic thrombocytopenic purpura. [1][2]

FDA milestone	Date	Commercial significance
Original Opana ER approval	2006	Established oxymorphone ER franchise
Reformulated Opana ER approval	2011	Added physical and chemical abuse-deterrence positioning
FDA withdrawal request	June 2017	Initiated market exit
Endo discontinuation and withdrawal process	2017	Ended branded commercial opportunity
FDA withdrawal determination	2018	Formalized withdrawal for safety reasons

FDA stated that the withdrawal was based on safety concerns, not a finding that the product was ineffective. The agency’s action was unusual because it requested withdrawal despite the product’s reformulated abuse-deterrent design. [1]

When did Opana ER lose exclusivity?

Opana ER lost its principal commercial exclusivity before the product was withdrawn. The relevant exclusivity value was affected by several factors:

• Expiration of the original product and formulation patents.
• ANDA approval and Paragraph IV certification activity.
• Regulatory exclusivity tied to the original NDA.
• Commercial withdrawal before a durable generic market developed.
• The limited size of the oxymorphone ER market after the opioid crisis intensified.

The precise patent-by-patent exclusivity analysis requires separating original formulation patents, reformulation patents, method-of-use patents and patents listed in the FDA Orange Book. Patent expiration should not be treated as equivalent to immediate generic launch because litigation, tentative approvals, controlled-substance manufacturing capacity and market withdrawal affected commercial timing.

What was the Orange Book status of Opana ER?

Opana ER was listed in FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book, under oxymorphone hydrochloride extended-release tablets. Orange Book listings can include patents covering drug substance, drug product and approved methods of use.

The commercially relevant Orange Book questions were:

Issue	Impact
Listed formulation patents	Could delay or complicate ANDA approval
Method-of-use patents	Could require carve-outs or litigation
Paragraph IV certifications	Could trigger patent litigation and a 30-month stay
Withdrawal from sale	Reduced the value of pending generic approvals
Controlled-substance requirements	Added manufacturing and distribution barriers

An Orange Book listing did not guarantee that a patent was valid or enforceable. It identified patents that the NDA holder represented as covering the approved product or use.

Which companies challenged Opana ER and what was the litigation risk?

Generic companies challenging opioid extended-release products commonly used Paragraph IV certifications against listed formulation and method-of-use patents. Opana ER’s patent environment included Endo and affiliated entities, with generic-drug manufacturers seeking approval for oxymorphone hydrochloride ER products.

The main litigation risks involved:

• Whether the asserted claims covered the proposed generic formulation.
• Whether the claims were valid over prior controlled-release opioid formulations.
• Whether a generic formulation could avoid abuse-deterrent claims.
• Whether the patent claims were sufficiently enabled across multiple polymer grades.
• Whether the proposed product required the same abuse-deterrent labeling.
• Whether withdrawal of the reference drug affected ANDA approval and commercial launch.

The withdrawal reduced the commercial value of litigation because the reference product was no longer actively marketed. A generic applicant still faced regulatory questions over whether an ANDA could rely on a withdrawn reference listed drug and whether FDA would require a different application pathway.

What commercial opportunities remain in Opana ER excipient technology?

The largest opportunity is technology transfer rather than revival of Opana ER itself. The same formulation concepts can support products with stronger market access prospects.

Abuse-deterrent opioid formulations

Excipient suppliers and formulation companies can license:

• High-viscosity polymer matrices.
• Crush-resistant direct-compression systems.
• Tamper-resistant coatings.
• Extraction-resistant tablets.
• Multiparticulate systems.
• Polymer systems that maintain controlled release after manipulation.

The commercial case is stronger for products where abuse-deterrent labeling is a regulatory or payer requirement and where the active ingredient has a substantial market.

Non-opioid extended-release medicines

A crush-resistant matrix can have value in non-opioid products where dose dumping, accidental misuse or altered administration is a concern. Potential targets include central nervous system medicines, sedatives, stimulant products and drugs requiring twice-daily dosing.

Non-opioid applications may provide a more favorable regulatory and reputational profile than opioid products while preserving the technical value of polymer-controlled release.

Excipient platform licensing

A platform owner can license:

• Polymer composition.
• Processing conditions.
• Tablet tooling.
• Dissolution methods.
• Abuse-deterrence test protocols.
• Scale-up and validation packages.
• Regulatory documentation supporting inactive-ingredient selection.

The license can be structured around an upfront fee, development milestones and product royalties. The most valuable package includes manufacturing know-how because excipient identity alone generally does not reproduce the finished product’s mechanical and dissolution properties.

How strong was the Opana ER patent estate?

The estate was technically meaningful but commercially weakened by the product’s withdrawal and the regulatory failure of the reformulated design.

Patent-estate factor	Assessment
Core controlled-release concept	Potentially vulnerable to extensive prior art
Specific polymer and matrix ranges	More defensible if tied to performance
Abuse-deterrent mechanics	Stronger where supported by reproducible test data
Manufacturing process claims	Potentially valuable and difficult to design around
Method-of-use claims	Dependent on approved labeling and infringement proof
Commercial enforceability	Reduced after product withdrawal
Platform licensing value	Remains possible outside oxymorphone

Patent strength should be assessed claim by claim. A patent claiming a broad sustained-release tablet is likely less valuable than one covering a defined matrix that demonstrates a particular combination of release control and mechanical resistance.

What manufacturing and IP barriers affect generic entry?

Generic entry faces more than patent expiration. The principal barriers are:

1. Access to suitable pharmaceutical-grade polymers.
2. Consistent polymer molecular weight and viscosity.
3. Blend uniformity at low and high tablet strengths.
4. Compression without capping or lamination.
5. Reproducible hardness and friability.
6. Demonstration of comparable dissolution.
7. Assessment of manipulated-product performance.
8. Controlled-substance registration and quota allocation.
9. FDA requirements for labeling and abuse-deterrent claims.
10. Commercial demand sufficient to support a controlled-substance manufacturing line.

A generic product may avoid a patented excipient combination but still encounter bioequivalence problems. For extended-release products, FDA can require comparisons across multiple dissolution conditions and, depending on the product and regulatory history, additional studies after physical manipulation.

How does Opana ER compare with other abuse-deterrent opioid products?

Product	Active ingredient	Abuse-deterrent approach	Market outcome
Opana ER	Oxymorphone hydrochloride	Crush-resistant and manipulation-resistant matrix	Withdrawn after FDA safety action
OxyContin OP	Oxycodone hydrochloride	Hard tablet and gelling polymer system	Continued commercial presence
Hysingla ER	Hydrocodone bitartrate	Hard tablet and polymer-based deterrence	Marketed under abuse-deterrent labeling
Xtampza ER	Oxycodone	Microsphere and fatty-acid-based formulation	Designed for abuse-deterrent administration flexibility
Arymo ER	Morphine sulfate	Crush-resistant tablet technology	Commercially limited relative to major opioid brands

Opana ER demonstrates that excipient-based abuse deterrence cannot be evaluated only through laboratory manipulation tests. FDA considered epidemiological and postmarketing evidence, including the route and consequences of abuse. [1][3]

What revenue exposure did the Opana ER withdrawal create?

The withdrawal eliminated Endo’s future revenue from branded Opana ER and impaired the value of related manufacturing, regulatory and patent assets. The precise revenue exposure depends on the reporting period, but the product was part of Endo’s branded pharmaceutical portfolio and its removal occurred during a broader decline in opioid sales.

The financial impact included:

• Loss of branded product revenue.
• Inventory write-downs and discontinuation costs.
• Reduced value of manufacturing capacity.
• Loss of future lifecycle-management revenue.
• Potential impairment of formulation and regulatory assets.
• Reduced leverage in licensing or generic settlement negotiations.

For investors and licensees, the key lesson is that abuse-deterrent excipient technology has platform value only if it is attached to a product with sustainable clinical demand, acceptable postmarketing risk and a viable reimbursement position.

What generic launch scenarios existed for Opana ER?

The realistic launch scenarios were:

Scenario	Commercial implication
Generic launch before withdrawal	Could create direct competition if patent and regulatory barriers were cleared
Generic launch after withdrawal	Dependent on FDA treatment of the withdrawn reference product
Authorized generic	Unlikely to create a durable market after brand discontinuation
Reformulated successor	Required a new commercial and regulatory strategy
Platform reuse	Most viable path for preserving excipient value

A successor product based on the same oxymorphone ER concept would face substantial clinical, regulatory and market-access barriers. A platform migration into another active ingredient or dosage form would generally offer better commercial prospects.

What geographic coverage applied to the Opana ER strategy?

The core commercial and regulatory value was concentrated in the United States because FDA approval, Orange Book listing, Paragraph IV litigation and abuse-deterrent labeling drove the product’s market position.

International opportunities would depend on:

• National approval of oxymorphone.
• Local controlled-substance rules.
• Patent term and supplementary protection rights.
• Availability of opioid safety data.
• Local requirements for tamper-resistant dosage forms.
• Market size and reimbursement.

The United States had the strongest commercial rationale for abuse-deterrent opioid technology but also the highest regulatory scrutiny.

Key Takeaways

• Opana ER used a controlled-release polymer matrix, with the reformulated version adding physical and chemical abuse-deterrent characteristics.
• The commercial product was withdrawn after FDA concluded that postmarketing injection abuse created an unfavorable benefit-risk balance.
• Excipient value resides in polymer selection, tablet mechanics, dissolution control and manufacturing know-how, not in a simple inactive-ingredient list.
• The main remaining opportunity is licensing the platform for other opioid or non-opioid extended-release products.
• Patent strength is highest when composition claims are tied to measurable abuse-deterrent and release performance.
• Generic entry was constrained by patent claims, bioequivalence requirements, controlled-substance regulation and limited post-withdrawal market demand.
• Opana ER is a weak candidate for commercial revival but remains a relevant case study in excipient-driven lifecycle management.

FAQs About Opana ER Excipient and Commercial Strategy

What polymer technology was associated with Opana ER?

Opana ER relied on hydrophilic matrix technology in which polymer swelling and gel formation moderated oxymorphone release. The reformulated product used additional physical properties to make crushing and manipulation more difficult.

Can a generic manufacturer copy Opana ER’s excipients?

A generic manufacturer can use the same or different inactive ingredients subject to FDA requirements, patent constraints and product-specific bioequivalence standards. Matching excipient names does not necessarily reproduce the reference product’s release or abuse-deterrent performance.

Is Opana ER still sold in the United States?

No. FDA requested withdrawal in 2017, and the product was removed from the U.S. market after the agency determined that its risks outweighed its benefits because of injection abuse concerns. [1][2]

Does Opana ER have biosimilar competition?

No. Opana ER is a chemically synthesized small-molecule drug, not a biologic. Competition would proceed through the generic-drug pathway rather than the biosimilar pathway.

Can Opana ER’s excipient strategy be used in a new drug?

Yes. The formulation principles can be adapted to other extended-release products, but any new product would require its own formulation development, patent analysis, manufacturing validation, bioequivalence program and FDA review.

References

1. U.S. Food and Drug Administration. (2017). FDA requests withdrawal of Opana ER for risks related to abuse. https://www.fda.gov/news-events/press-announcements/fda-requests-withdrawal-opana-er-risks-related-abuse

2. U.S. Food and Drug Administration. (2018). Determination that OPANA ER (oxymorphone hydrochloride) extended-release tablets, 5 mg and 10 mg, were withdrawn from sale for reasons of safety or effectiveness. Federal Register.

3. U.S. Food and Drug Administration. (2020). Abuse-deterrent opioid analgesics: Evaluation and labeling. https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/abuse-deterrent-opioid-analgesics-evaluation-and-labeling

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.

5. Endo Pharmaceuticals Inc. (2011). Opana ER prescribing information. U.S. Food and Drug Administration.