List of Excipients in Branded Drug OPANA

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
STAT Rx USA LLC	OPANA	oxymorphone hydrochloride	16590-765	D&C RED NO. 30
STAT Rx USA LLC	OPANA	oxymorphone hydrochloride	16590-765	LACTOSE MONOHYDRATE
STAT Rx USA LLC	OPANA	oxymorphone hydrochloride	16590-765	MAGNESIUM STEARATE
STAT Rx USA LLC	OPANA	oxymorphone hydrochloride	16590-765	STARCH, CORN

Last updated: August 22, 2026

Opana’s commercial value now lies in oxymorphone formulation technology, generic supply, abuse-deterrent excipients, and controlled-release platforms rather than in the discontinued branded product. The strongest opportunity is a differentiated extended-release or abuse-deterrent oxymorphone product supported by a 505(b)(2) or ANDA strategy, but regulatory and market risks are high because the FDA required withdrawal of Opana ER after concluding that its reformulation did not adequately reduce opioid abuse and may have increased injection-related risks.

Opana Excipient Strategy and Commercial Opportunities for Oxymorphone

What is Opana and why does its excipient strategy matter?

Opana is the former Endo Pharmaceuticals brand for oxymorphone hydrochloride, a semisynthetic opioid analgesic. The product was marketed in immediate-release tablets and as Opana ER, an extended-release formulation.

The excipient strategy matters for three reasons:

1. Oxymorphone has a narrow commercial market and requires reliable dose uniformity.
2. Extended-release delivery depends on matrix-forming polymers and manufacturing controls.
3. Any abuse-deterrent claim requires formulation-specific evidence, not merely the inclusion of a particular excipient.

Opana ER was withdrawn from the U.S. market in 2017 after the FDA determined that the product’s benefits no longer outweighed its risks. The FDA’s action was linked to postmarketing evidence involving abuse by injection and transmission of HIV and hepatitis C among people who injected the product. [1]

The commercial opportunity has therefore shifted from branded Opana sales to platform technologies that can deliver controlled release, improve tamper resistance, or enable differentiated generic and 505(b)(2) products.

Which excipients were used in Opana formulations?

Public labeling identifies different excipient systems for immediate-release and extended-release oxymorphone products. Exact composition varies by dosage strength, coating system, and formulation version.

Immediate-release Opana

Immediate-release tablets used conventional solid oral excipients, including combinations of:

• Lactose or other diluents
• Microcrystalline cellulose
• Pregelatinized starch
• Crospovidone or related disintegrants
• Magnesium stearate
• Film-coating materials
• Pharmaceutical pigments or opacifiers

The formulation objective was rapid tablet disintegration and predictable oxymorphone release. Immediate-release products generally offer limited formulation differentiation because the excipient system is conventional and readily replicated.

Commercially relevant excipient functions include:

Function	Typical excipient category	Commercial objective
Dilution	Lactose, microcrystalline cellulose	Dose uniformity and tablet weight
Disintegration	Starch, crospovidone	Rapid release after administration
Lubrication	Magnesium stearate	Tablet manufacturability
Film coating	Hypromellose-based systems	Identification, swallowability, moisture control
Color control	Iron oxides, titanium dioxide or equivalent pigments	Product differentiation and visual identification

Opana ER

Opana ER used a hydrophilic and polymer-based controlled-release system. The reformulated version incorporated proprietary abuse-deterrent technology associated with Endo’s INTAC platform.

Relevant excipient categories in an extended-release opioid matrix include:

• High-viscosity hydrophilic polymers
• Polyethylene oxide or related matrix-forming polymers
• Hypromellose
• Cellulosic binders
• Lubricants and glidants
• Film-coating materials
• pH-modifying or release-controlling excipients

These materials regulate water penetration, polymer hydration, gel formation, diffusion, and erosion. The commercial value is created by the interaction between polymer grade, particle size, compression force, tablet porosity, coating, and manufacturing conditions.

A generic applicant cannot assume that substituting one polymer for another will preserve the reference product’s release profile. For modified-release products, excipient grade and process parameters can materially affect dissolution, food effect, dose dumping, and pharmacokinetics.

What excipient strategy is best for a new Opana-related product?

The most defensible strategy is a tiered platform rather than a direct copy of the historical Opana formulation.

Strategy 1: Conventional immediate-release tablet

A conventional immediate-release oxymorphone tablet has the lowest technical barrier. The formulation can use well-established excipients and standard direct-compression or wet-granulation processes.

Commercial advantages include:

• Lower development cost
• Familiar regulatory pathway
• Broad availability of compendial excipients
• Lower manufacturing complexity
• Reduced need for specialized abuse-deterrence testing

The disadvantages are substantial. Immediate-release opioids face intense regulatory scrutiny, limited prescribing growth, restricted promotional flexibility, and competition from other analgesics. The product also has limited formulation-based differentiation.

Strategy 2: Generic extended-release tablet

An extended-release product offers stronger differentiation but requires tighter control of:

• Dissolution across multiple media and agitation conditions
• Alcohol-induced dose dumping
• Fed and fasted pharmacokinetics
• Tablet crushing and particle manipulation
• Batch-to-batch polymer variability
• Manufacturing scale-up
• Stability under heat and humidity

A generic extended-release product normally needs to demonstrate pharmaceutical equivalence and bioequivalence under the applicable FDA pathway. The reference product’s inactive ingredients may be duplicated, modified, or replaced, but any difference must not affect safety, performance, or regulatory equivalence.

Strategy 3: Abuse-deterrent formulation

An abuse-deterrent formulation can use excipients that make the dosage form difficult to crush, dissolve, extract, or inject. Candidate technologies include:

• High-molecular-weight polyethylene oxide matrices
• High-viscosity hydrophilic polymers
• Gelling agents
• Ion-exchange resins
• Thermoplastic or hardening excipient systems
• Sequestration agents
• Multiphase tablets
• Coatings that resist mechanical and solvent manipulation

The FDA evaluates abuse deterrence by route and manipulation method. The agency distinguishes laboratory-based Category 1 studies, pharmacokinetic studies, human abuse-potential studies, and postmarketing outcomes. No formulation can be described as abuse-proof. [2]

The commercial risk is especially high for oxymorphone because the prior Opana ER reformulation was itself intended to deter abuse but was withdrawn after the FDA concluded that the product did not meet the broader public-health standard. [1]

What patents protected Opana and its controlled-release technology?

Opana’s historical patent position included patents covering oxymorphone formulations, controlled-release dosage forms, and abuse-deterrent technology. The core small-molecule composition-of-matter protection for oxymorphone was not the primary barrier by the time Opana ER was commercialized.

Public patent records associated with Opana-related technology include:

Patent	General subject matter	Commercial relevance
U.S. Patent No. 5,662,933	Oxymorphone oral dosage forms and formulations	Historical formulation protection; generally expired
U.S. Patent No. 8,337,886	Abuse-resistant or abuse-deterrent controlled-release opioid dosage form	Relevant to the INTAC-type platform and formulation design
Related continuation and formulation patents	Controlled release, tamper resistance, and dosage-form architecture	Scope depends on claim language, prosecution history, and expiration

Patent analysis must separate three layers:

1. Oxymorphone active-ingredient patents.
2. Extended-release formulation patents.
3. Abuse-deterrent manufacturing and dosage-form patents.

Expired composition or basic formulation patents do not eliminate risk from later patents covering polymer combinations, tablet architecture, manufacturing processes, or specific abuse-deterrence performance.

When did Opana lose exclusivity and what is its FDA status?

Opana no longer has an active branded commercial position in the United States.

Event	Date	Significance
Opana ER approved	2006	FDA approval of extended-release oxymorphone
Reformulated Opana ER approved	2011	Introduction of an abuse-deterrent formulation
FDA requested withdrawal	June 2017	Agency concluded benefit-risk balance was unfavorable
Endo withdrawal completed	2017	Opana ER removed from the U.S. market
FDA final action	2017	First instance in which FDA requested opioid withdrawal for abuse-related public-health reasons

The original Opana ER product was not withdrawn because it failed to meet manufacturing specifications. The FDA’s action concerned population-level abuse and public-health consequences. [1]

The immediate-release brand also does not represent a meaningful current commercial franchise. Any present opportunity would depend on generic or reformulated development rather than revival of the original brand.

What is the Orange Book status of Opana?

The Orange Book historically listed Opana and Opana ER reference products with associated patent and exclusivity information. Because the products have been discontinued, current commercial relevance depends on whether the reference listed drug remains eligible for ANDA referencing and whether the FDA identifies a currently marketed reference product.

Important distinctions include:

• A drug can remain listed in FDA records after commercial discontinuation.
• Discontinued status does not automatically eliminate all patent or regulatory barriers.
• An ANDA applicant must evaluate reference-product eligibility, withdrawal status, product-specific guidance, and any applicable FDA determinations.
• A 505(b)(2) applicant may face different reliance and exclusivity issues from an ANDA applicant.

For an oxymorphone product, the regulatory strategy should be selected after reviewing the current FDA Orange Book listing, discontinued-drug status, product-specific guidance, and any applicable patents or exclusivity records. [3]

Are Paragraph IV challenges relevant to Opana?

Paragraph IV risk is more relevant to any remaining listed patents or later-developed oxymorphone formulations than to the original basic Opana patents.

A generic applicant could use a Paragraph IV certification against an unexpired listed patent if the applicant contends that:

• The patent is invalid.
• The patent is unenforceable.
• The proposed product does not infringe.

Potential dispute areas include:

• Polymer composition
• Abuse-deterrent matrix structure
• Release-rate parameters
• Tablet hardness and porosity
• Manufacturing steps
• Use of the product in specific pain conditions

A Paragraph IV filing could trigger patent litigation and a statutory 30-month stay if the relevant conditions are satisfied. That mechanism is less commercially important for expired historical patents but could matter if later patents remain listed or if a new 505(b)(2) product creates a separate patent estate.

What formulation patents are most valuable for oxymorphone?

The highest-value claims are likely to cover measurable technical performance rather than broad excipient selection.

High-value patent claim categories

• Specific polymer molecular-weight ranges
• Defined polymer-to-drug ratios
• Controlled-release profiles across multiple dissolution conditions
• Resistance to crushing or grinding
• Reduced extraction in aqueous, alcoholic, or organic solvents
• Gel strength after hydration
• Sequestered antagonist systems
• Multilayer or multiparticulate dosage forms
• Manufacturing methods that create tamper-resistant hardness or porosity
• Food-effect reduction
• Dose-dumping prevention

A patent that claims only a common excipient, such as hypromellose or magnesium stearate, is generally weaker than one that claims a narrow formulation architecture with demonstrated performance.

Manufacturing and trade-secret barriers

Commercial protection may also arise from non-patent know-how:

• Polymer hydration control
• Granulation endpoint
• Compression-force windows
• Coating thickness
• Moisture conditioning
• Scale-up parameters
• In-process hardness testing
• Dissolution-control methods

These controls can create a practical barrier even when a patent estate is narrow. They are difficult to evaluate through public documents and may remain protected as trade secrets.

Which companies are positioned to challenge or replace Opana?

The competitive field is broader than branded opioid manufacturers. Relevant participants include:

• Generic pharmaceutical companies with controlled-release tablet capabilities
• Specialty opioid developers
• Abuse-deterrent technology licensors
• Excipient manufacturers
• Contract development and manufacturing organizations
• Companies developing non-opioid pain therapies

The strongest potential partners are companies with:

1. FDA experience in modified-release ANDAs or 505(b)(2) applications.
2. In-house dissolution and abuse-deterrence testing.
3. Access to high-viscosity polymer supply.
4. Experience with Schedule II distribution controls.
5. Commercial infrastructure for restricted opioid products.

Excipient suppliers can capture value through formulation partnerships, technical services, and preferred-grade supply agreements. A supplier with a validated polymer grade and established regulatory documentation may have greater leverage than a commodity excipient supplier.

What licensing opportunities exist for Opana-related technology?

Licensing opportunities fall into four categories.

Excipient and polymer licensing

A polymer supplier can license:

• Proprietary high-viscosity grades
• Controlled-release matrix systems
• Tamper-resistant excipient blends
• Formulation development packages
• Regulatory support and master-file access

Abuse-deterrence platform licensing

A technology owner may license a complete platform covering:

• Tablet architecture
• Crush resistance
• Solvent resistance
• Extraction resistance
• Manufacturing processes
• Human abuse-potential data

505(b)(2) product licensing

A developer could license an oxymorphone formulation with differentiated release, dosing, or abuse-deterrent characteristics. The value depends on whether the product offers a clinically meaningful advantage and whether the FDA accepts the proposed reliance pathway.

Manufacturing and supply agreements

Commercial terms may include:

• Exclusive polymer supply
• Dual-source obligations
• Minimum annual volumes
• Price adjustment mechanisms
• Regulatory change controls
• Technology-transfer fees
• Quality agreements
• Geographic field restrictions

For a controlled substance, supply agreements also need chain-of-custody controls, quota planning, diversion monitoring, and secure manufacturing provisions.

How strong is the patent estate for a new Opana formulation?

A new oxymorphone formulation could obtain meaningful protection, but patent strength would depend on claim specificity and clinical differentiation.

Protection layer	Likely strength	Main weakness
Conventional immediate-release excipient blend	Low	Easy design-around
Basic extended-release polymer matrix	Moderate to low	Prior-art density
Specific abuse-deterrent architecture	Moderate to high	Regulatory-performance burden
Manufacturing process	Moderate	Difficult infringement detection
New dosage regimen or indication	Moderate	Requires clinical support
Combination product	Potentially high	Development and safety complexity
Proprietary excipient grade	Trade-secret value	Limited patent exclusivity

The most credible estate would combine formulation claims, process claims, use claims, and know-how. A single broad polymer claim would face significant obviousness and prior-art risk.

What generic launch risks exist for oxymorphone?

The principal risks are regulatory, commercial, and liability-related.

Regulatory risks

• FDA concern over opioid abuse potential
• Difficulty demonstrating equivalent abuse-deterrent performance
• Product-specific requirements for modified release
• Manufacturing deviations affecting dissolution
• Controlled-substance quota constraints
• Labeling limitations

Commercial risks

• Small and declining opioid market
• Restricted insurer coverage
• Low prescriber adoption
• Price compression from generic entry
• Inventory and quota management
• High compliance costs

Litigation risks

• Paragraph IV patent litigation
• Product-liability claims
• Allegations involving diversion or inadequate warnings
• Patent disputes over polymer architecture and manufacturing
• Contract disputes involving controlled-substance supply

A conventional generic may launch at lower development cost but face rapid price erosion. A differentiated abuse-deterrent product may retain better pricing but requires substantially higher clinical, analytical, and regulatory investment.

How does Opana compare with other abuse-deterrent opioids?

Opana ER is a cautionary case for abuse-deterrent development. The product received abuse-deterrent labeling based on laboratory and pharmacokinetic evidence, but the FDA later concluded that postmarket public-health outcomes justified withdrawal. [1]

The comparison is commercially important:

Product type	Formulation barrier	Regulatory burden	Commercial outlook
Conventional immediate-release opioid	Low	Standard opioid controls	Low differentiation
Conventional extended-release opioid	Moderate	Modified-release requirements	Higher technical barrier
Abuse-deterrent extended-release opioid	High	Abuse-deterrence and postmarket scrutiny	Potential pricing premium, high risk
Non-opioid analgesic	Variable	Depends on mechanism	May offer stronger long-term positioning

Abuse-deterrent labeling is not equivalent to elimination of abuse risk. The FDA evaluates whether the product meaningfully reduces abuse by specific routes and whether real-world evidence supports the overall benefit-risk profile. [2]

What is the commercial opportunity for excipient suppliers?

The best opportunities are upstream and platform-based.

Near-term opportunities

• Supply of high-viscosity release-controlling polymers
• Direct-compression excipient systems for opioid tablets
• Technical support for dissolution matching
• Custom coating and color systems
• Stability-enhancing excipient packages
• Analytical support for extractables and leachables

Higher-value opportunities

• Co-developed abuse-deterrent matrices
• Proprietary polymer grades
• Formulation patents jointly owned with a drug developer
• Regulatory master files
• Exclusive supply arrangements
• Platform licensing across multiple opioid products

The supplier’s strongest negotiating position comes from a formulation that depends on a narrowly specified excipient grade and manufacturing process. Commodity excipients have limited pricing power unless they are tied to regulatory equivalence, validated performance, or dual-source restrictions.

What geographic markets remain relevant?

The United States is the most difficult market because of opioid controls, FDA scrutiny, litigation exposure, and the history of Opana ER withdrawal.

Other markets may present opportunities for oxymorphone products, but market access depends on:

• National opioid scheduling
• Local controlled-substance quotas
• Reference-product status
• Reimbursement
• Local patent rights
• Abuse-deterrence expectations
• Import and distribution controls

A formulation patent may have value in one jurisdiction and no remaining protection in another. International patent strategy should focus on countries with meaningful opioid use, local manufacturing capability, and enforceable pharmaceutical patent systems.

Key Takeaways

• Opana is no longer a viable U.S. branded commercial franchise.
• The main opportunity is oxymorphone formulation technology, not brand revival.
• Immediate-release products offer lower development complexity but limited differentiation.
• Extended-release and abuse-deterrent products offer stronger IP potential but face substantial regulatory risk.
• The Opana ER withdrawal makes postmarket abuse outcomes central to any commercial strategy.
• High-value excipient opportunities involve proprietary polymer grades, validated matrix systems, and technical partnerships.
• Formulation patents should be supported by process claims, use claims, and manufacturing know-how.
• A generic or 505(b)(2) launch must address Orange Book status, reference-product eligibility, Paragraph IV risk, controlled-substance quotas, and opioid-specific FDA scrutiny.
• The strongest commercial model is a platform that can be reused across multiple modified-release or abuse-deterrent products.

FAQs

Can a company still develop a generic version of Opana?

Potentially, but the regulatory pathway depends on the current FDA reference-product status, market availability, formulation type, and applicable patents. Immediate-release and extended-release oxymorphone require different development strategies.

Which excipient is most important in an Opana ER-type formulation?

The release-controlling polymer system is generally the most important excipient component. Polymer molecular weight, viscosity, concentration, particle size, and compression behavior can materially affect release and tamper resistance.

Does an abuse-deterrent excipient guarantee FDA approval?

No. FDA review considers the complete formulation, laboratory manipulation studies, pharmacokinetics, abuse-potential data where applicable, manufacturing controls, labeling, and postmarket evidence.

Could a new oxymorphone formulation qualify for 505(b)(2) exclusivity?

A 505(b)(2) application may be possible if the product relies partly on FDA findings for an approved drug while incorporating a new formulation, route, dosage regimen, or other change. Any exclusivity would depend on the approved innovation and FDA determination.

Are Opana excipients themselves patentable?

A conventional excipient is rarely patentable in isolation. Patent value is more likely to arise from a specific excipient combination, defined formulation performance, dosage-form architecture, or manufacturing process.

References

1. U.S. Food and Drug Administration. (2017). FDA requests removal of Opana ER for risks related to abuse. https://www.fda.gov
2. U.S. Food and Drug Administration. (2015). Abuse-deterrent opioids: Evaluation and labeling. https://www.fda.gov
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov
4. U.S. Food and Drug Administration. (2011). Opana ER prescribing information. Endo Pharmaceuticals.
5. U.S. Patent and Trademark Office. (2012). U.S. Patent No. 8,337,886, abuse-resistant controlled-release opioid dosage form. Washington, DC.
6. U.S. Patent and Trademark Office. (1987). U.S. Patent No. 5,662,933, oxymorphone oral dosage forms and formulations. Washington, DC.