United States Drug Patent 7,674,800: Claim Scope, Expiration, Litigation Risk, and Oxycodone Patent Landscape

US Patent No. 7,674,800 is a process and product-by-process patent directed to reducing 14-hydroxycodeinone in oxycodone salts, particularly oxycodone hydrochloride. Its central technical concept is the controlled conversion of an 8α,14-dihydroxy-7,8-dihydrocodeinone impurity into 14-hydroxycodeinone during salt formation, followed by selective removal or hydrogenation of that impurity to produce oxycodone hydrochloride containing less than specified parts-per-million levels.

The patent does not claim oxycodone as a molecule, an oxycodone tablet, an abuse-deterrent formulation, or a method of treating pain. Its principal commercial relevance is to manufacturers of oxycodone active pharmaceutical ingredient and oxycodone hydrochloride who use an acid-mediated salt-formation step followed by impurity reduction.

What does US Patent 7,674,800 cover?

US 7,674,800 covers three related claim categories:

Claim category	Claims	Core subject matter
Manufacturing process	1-29 and 57-75	Preparing an oxycodone salt and reducing 14-hydroxycodeinone
Product-by-process oxycodone salt	30-37 and 76-80	Oxycodone salt prepared by the claimed process
Low-impurity oxycodone hydrochloride composition	38-56 and 81	Oxycodone hydrochloride containing specified impurity levels after hydrogenation

The broadest independent process claims are claims 1 and 57. Claim 1 requires:

Oxycodone free base containing an 8α,14-dihydroxy-7,8-dihydrocodeinone component.
A solvent and acid.
Incubation under conditions that convert the free base into an oxycodone salt.
Acid-catalyzed dehydration of the impurity to 14-hydroxycodeinone.
Preferential removal of the 14-hydroxycodeinone.

Claim 57 is similar but uses broader functional language. It requires reducing the amount of 14-hydroxycodeinone to produce an oxycodone salt composition containing less than 25 ppm of the impurity.

What technical problem does the patent address?

The patent addresses impurity formation during oxycodone salt preparation. The starting oxycodone free base contains an 8α,14-dihydroxy-7,8-dihydrocodeinone component. Under acidic conditions, particularly during hydrochloride salt formation, that component undergoes dehydration and forms 14-hydroxycodeinone.

The patent therefore treats salt formation as a two-stage impurity problem:

Stage	Transformation
Starting material	Oxycodone free base containing 8α,14-dihydroxy-7,8-dihydrocodeinone
Acidic salt formation	Dehydration to 14-hydroxycodeinone
Purification or hydrogenation	Removal or conversion of 14-hydroxycodeinone
Final product	Low-impurity oxycodone salt, especially oxycodone hydrochloride

The claims are drafted around the process sequence rather than around a particular commercial tablet or dosage form.

How broad are the independent claims?

Claim 1

Claim 1 is broad in the choice of:

Solvent.
Acid.
Temperature.
Purification method.
Hydrogenation system.
Final impurity concentration, because claim 1 itself does not specify a numerical limit.

Its principal limiting elements are the presence of the specified impurity precursor and the requirement that acid-catalyzed dehydration occur during salt formation. A process that forms oxycodone hydrochloride without the claimed precursor, or without converting that precursor into 14-hydroxycodeinone under the claimed conditions, has a stronger non-infringement position.

The claim also requires preferential removal of 14-hydroxycodeinone from the oxycodone salt. That language is broader than a specific chromatography or hydrogenation protocol, because dependent claims identify chromatography, gels, slurry treatment, and hydrogenation as alternative techniques.

Claim 57

Claim 57 is functionally broader in one respect. It requires reducing the amount of 14-hydroxycodeinone to produce a composition containing less than 25 ppm, but it does not limit the reduction step to chromatography, hydrogenation, or a gel.

The claim still requires the acid-catalyzed formation of 14-hydroxycodeinone from the 8α,14-dihydroxy-7,8-dihydrocodeinone component. This precursor-to-impurity relationship is a central claim limitation.

Claim 38

Claim 38 is more process-specific. It requires:

Oxycodone free base.
Solvent.
Hydrochloric acid.
Formation of oxycodone hydrochloride containing more than 100 ppm 14-hydroxycodeinone.
Hydrogenation of that material.
Reduction to less than 25 ppm.
A showing that at least part of the 14-hydroxycodeinone originated from the specified precursor.

Claims 38-56 are commercially important because they connect a high-impurity intermediate to a hydrogenation step and then to a defined low-impurity oxycodone hydrochloride composition.

What process conditions are protected?

The dependent claims establish several process variables.

Variable	Claimed range or limitation
Temperature	About 20°C; about 40°C to 85°C; about 75°C
pH	About 2.5 or less, with narrower limits of 1.8, 1.5, and 1.0
Acid loading	More than 1.0 equivalent; narrower limits above 1.2, 1.4, and 1.5 equivalents
Acid	Hydrochloric acid is specifically claimed
Hydrogenation time	About 10 minutes to 36 hours; narrower claims cover at least 4 hours, 5 hours, and about 21 hours
Purification	Chromatography, gel treatment, slurry treatment, or hydrogenation
Hydrogenation system	Catalyst plus hydrogen or a hydrogen-transfer reagent
Final impurity level	Less than 25, 15, 10, or 5 ppm

The claim set does not require every listed condition. For example, claim 1 does not require hydrochloric acid, a pH below 1, or heating to 75°C. Those limitations arise in dependent claims and narrower claim families.

What formulations are protected by US 7,674,800?

The patent does not directly protect an oxycodone tablet formulation, extended-release matrix, capsule, oral solution, or abuse-deterrent dosage form.

Its composition claims concern oxycodone salts and oxycodone hydrochloride defined by their preparation and impurity profile. Claim 56 states that the composition is suitable for use in a commercial oxycodone product, but that language does not convert the patent into a conventional formulation patent.

The practical scope is therefore concentrated in:

Oxycodone API manufacture.
Oxycodone hydrochloride crystallization.
Impurity control.
Hydrogenative purification.
Commercial supply of low-14-hydroxycodeinone oxycodone hydrochloride.

A finished dosage-form manufacturer that purchases compliant oxycodone hydrochloride from an independent API supplier may not practice the claimed manufacturing process itself. Infringement analysis would depend on the supply chain, contractual arrangements, importation, and the specific product-by-process claims.

What impurity limits are claimed?

The patent claims a descending series of 14-hydroxycodeinone thresholds.

Claim threshold	Relevant claims
Less than 25 ppm	19, 32, 38, 57, 73, 78
Less than 15 ppm	20, 33, 46, 50, 79
Less than 10 ppm	21, 34, 51, 74
Less than 5 ppm	22, 35, 52, 75
0.5 to 25 ppm	80
Lower limits including 0.25, 0.5, 1, 2, or 5 ppm	55 and 81

The concentration limitation alone is not necessarily sufficient for infringement. Many claims combine the impurity threshold with process history, including the origin of the impurity and the use of hydrogenation. A product containing less than 5 ppm may fall outside a particular claim if it was made without the required starting impurity or process sequence.

Is US 7,674,800 an Orange Book patent?

US 7,674,800 is principally an API manufacturing patent, not a conventional drug-product patent. Orange Book listing depends on whether the patent claims the approved drug product, an approved formulation, or an approved method of use in a manner eligible for listing under FDA rules.

Process patents directed to preparation of the active ingredient generally do not create the same Orange Book exposure as patents claiming an approved oxycodone dosage form or method of use. A current Orange Book determination must be made against the specific oxycodone product and listing history, rather than inferred from the patent number alone. FDA’s Orange Book identifies approved drug products and eligible patent or exclusivity information; it is not a complete register of all manufacturing patents affecting an API [2].

The patent should therefore be treated as an API and supply-chain patent unless an applicable FDA listing identifies it for a particular approved product.

When does US Patent 7,674,800 lose exclusivity?

The patent term is generally measured from the applicable nonprovisional filing date or earliest effective priority date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and maintenance-fee status. The issue date alone does not determine expiration.

US 7,674,800 was issued on March 9, 2010. The public patent record identifies it as a Purdue-associated oxycodone process patent and places its ordinary term in the mid-2020s, subject to the official USPTO term calculation and any adjustments recorded in the patent file [1, 3].

Milestone	Date or significance
Patent issued	March 9, 2010
Patent type	Utility process and product-by-process patent
Primary subject	Low-14-hydroxycodeinone oxycodone salts
Expected ordinary term	Mid-2020s, based on the effective filing and priority record
Controlling status source	USPTO Patent Center and official patent-term data

A freedom-to-operate opinion should use the USPTO record for the precise expiration date and maintenance status. A patent can also become unenforceable before its nominal expiration if maintenance fees are not paid, although reinstatement may be possible under applicable USPTO procedures.

What Paragraph IV challenges affect the patent?

A Paragraph IV certification applies to a listed patent in an abbreviated new drug application context. It is not automatically triggered by every patent that relates to oxycodone manufacture.

For US 7,674,800, the key threshold question is whether the patent is listed against the relevant reference-listed drug and whether the ANDA applicant’s product would implicate the listed claims. If the patent is not listed for the relevant drug product, a Paragraph IV certification against it would generally not be the principal ANDA pathway.

The claim structure creates several potential Paragraph IV positions if the patent is listed:

Non-infringement because the generic manufacturer does not use the claimed precursor or acid-mediated conversion.
Non-infringement because the final purification does not preferentially remove 14-hydroxycodeinone as claimed.
Invalidity for anticipation or obviousness based on earlier oxycodone purification and hydrogenation disclosures.
Indefiniteness or written-description challenges directed to functional terms such as “preferentially removing” and “substantially free.”
Lack of infringement of product-by-process claims because the oxycodone hydrochloride was not made by the claimed process.

A generic tablet applicant may also avoid direct process exposure by sourcing API from a supplier that uses a non-infringing route. That approach does not eliminate all importation or induced-infringement issues, but it changes the factual posture.

How strong is the patent estate?

The patent has meaningful technical breadth but a narrower commercial perimeter than an oxycodone formulation patent.

Strengths

It covers the impurity precursor, the acid-mediated formation of 14-hydroxycodeinone, and its subsequent reduction.
It includes multiple purification alternatives.
It claims several commercially relevant impurity thresholds.
It covers both process claims and product-by-process compositions.
It includes hydrochloric acid, common in oxycodone hydrochloride production.

Vulnerabilities

The patent depends heavily on proving the origin and transformation of the impurity.
“Preferentially removing” may require technical evidence comparing impurity removal against oxycodone retention.
Product-by-process claims may be difficult to enforce against a product made by a materially different process.
Hydrogenation of unsaturated opioid impurities may be vulnerable to obviousness arguments if analogous chemistry was known.
A process that avoids the specified 8α,14-dihydroxy-7,8-dihydrocodeinone precursor may fall outside the principal claim architecture.
A low impurity level alone does not necessarily establish infringement.

The strongest enforcement scenario would involve a manufacturer using oxycodone free base with the specified precursor, forming oxycodone hydrochloride under acidic conditions, generating more than 100 ppm 14-hydroxycodeinone, and then applying hydrogenation to reach the claimed limits.

What manufacturing and IP barriers does the patent create?

The patent can create barriers at three points in the API supply chain:

Starting-material control

A manufacturer must characterize whether its oxycodone free base contains the claimed 8α,14-dihydroxy-7,8-dihydrocodeinone component. Analytical characterization is central to both infringement and invalidity disputes.

Salt-formation control

Acid concentration, pH, temperature, residence time, and solvent selection can affect whether the precursor converts into 14-hydroxycodeinone. Process records and batch data would be relevant in litigation.

Purification control

Hydrogenation, chromatography, gel adsorption, and slurry treatment may produce different impurity profiles. A non-infringing route could rely on:

Removal of the precursor before salt formation.
Salt formation under conditions that do not promote the claimed dehydration.
A different impurity-reduction chemistry.
A process that does not use the claimed hydrogenation or preferential-removal sequence.
A supplier with a documented alternative manufacturing route.

How does this patent compare with oxycodone formulation patents?

Issue	US 7,674,800	Oxycodone formulation patent
Primary subject	API process and impurity control	Tablet, capsule, matrix, coating, or release profile
Product claim	Oxycodone salt by process	Finished dosage form
Key evidence	Starting impurity, acid conditions, purification, ppm level	Ingredients, structure, release data, dosage form
Generic risk	API supplier and manufacturing route	ANDA formulation and bioequivalence product
Orange Book relevance	Product-specific and potentially limited	Often more direct if eligible and listed
Design-around path	Alter precursor, salt formation, or purification	Change excipients, release mechanism, or dosage form

The patent is most relevant to API producers and integrated manufacturers. It is less likely to block a generic solely because the generic sells an oxycodone tablet with the same active ingredient.

What licensing and litigation issues are relevant?

A license covering a finished oxycodone product may not necessarily authorize practice of a separate API manufacturing patent. Supply agreements should identify:

Whether the API supplier owns or licenses the relevant process.
Whether the license covers US manufacture and importation.
Whether product-by-process claims are included.
Whether the supplier provides indemnification for patent claims.
Whether the process changed after patent issuance.
Whether regulatory filings disclose the manufacturing route.

The relevant litigation record should be checked through PACER, USPTO Patent Center, and commercial patent litigation databases. The patent number alone does not establish that a current district-court case, ANDA case, or settlement agreement exists.

Key Takeaways

US 7,674,800 is directed to oxycodone API manufacture and impurity reduction.
Its central mechanism is acid-catalyzed conversion of 8α,14-dihydroxy-7,8-dihydrocodeinone into 14-hydroxycodeinone during oxycodone salt formation.
The patent covers removal by hydrogenation, chromatography, gels, slurry treatment, and related preferential-removal techniques.
The principal commercial target is low-impurity oxycodone hydrochloride, with claimed levels below 25, 15, 10, and 5 ppm.
The patent does not directly claim oxycodone as a molecule or a conventional oxycodone dosage-form formulation.
Paragraph IV risk depends first on Orange Book listing and then on whether the generic’s API manufacturing route practices the claimed process.
A design-around strategy can focus on the starting impurity, acid-mediated salt formation, or the impurity-reduction step.
The patent’s ordinary term falls in the mid-2020s based on the public filing and issue record, subject to official USPTO term calculations and maintenance status.

FAQs About US Patent 7,674,800

Does US 7,674,800 cover oxycodone hydrochloride tablets?

No. It primarily covers processes for preparing low-14-hydroxycodeinone oxycodone salts and compositions made by those processes. It does not broadly claim a tablet or extended-release dosage form.

What is the key impurity in US 7,674,800?

The key impurity is 14-hydroxycodeinone. The patent links its formation to acid-catalyzed dehydration of an 8α,14-dihydroxy-7,8-dihydrocodeinone component in oxycodone free base.

Can a manufacturer avoid the patent by producing oxycodone with less than 5 ppm impurity?

Not necessarily. The impurity level is only one limitation in several claims. Infringement may also depend on the starting material, salt-formation conditions, impurity origin, and reduction method.

Is hydrogenation required by every claim?

No. Hydrogenation is required by several important dependent and composition claims, including claim 38 and its dependents, but the broader process claims also cover chromatography and other preferential-removal techniques.

Does patent expiration eliminate all oxycodone patent risk?

No. Expiration of US 7,674,800 would eliminate enforceability of that patent after the applicable term, but other patents may cover oxycodone formulations, abuse-deterrent technologies, methods of use, manufacturing processes, or regulatory exclusivities.

References

United States Patent and Trademark Office. (2010). U.S. Patent No. 7,674,800, Process for preparing oxycodone. Washington, DC: U.S. Department of Commerce.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: The Orange Book. Silver Spring, MD: U.S. Department of Health and Human Services.
United States Patent and Trademark Office. (2024). Patent Center and patent term adjustment information. Washington, DC: U.S. Department of Commerce.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	2232	⤷ Start Trial
Argentina	049012	⤷ Start Trial
Argentina	118531	⤷ Start Trial
Argentina	124161	⤷ Start Trial
Austria	9952	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,674,800

Summary for Patent: 7,674,800