US Patent 7,674,800 (United States) : What the claims cover, how broad they are, and where the patent fence sits

US Drug Patent 7,674,800 claims a process to make oxycodone salts substantially free of 14-hydroxycodeinone, where the process drives an acid-catalyzed dehydration of an 8α,14-dihydroxy-7,8-dihydrocodeinone component to 14-hydroxycodeinone, then removes or reduces that impurity to a low parts-per-million (ppm) specification.

What is the core invention in US 7,674,800?

Claim 1 is the independent claim and defines the invention’s essential sequence:

Start material state: prepare a mixture of:
- oxycodone free base
- solvent
- acid
- where the free base contains an 8α,14-dihydroxy-7,8-dihydrocodeinone component
In-situ formation of impurity under acid catalysis (acid dehydration):
- incubate under conditions “suitable” to convert the free base to an oxycodone salt
- where the conditions promote acid-catalyzed dehydration
- specifically converting the 8α,14-dihydroxy-7,8-dihydrocodeinone component to 14-hydroxycodeinone
Preferential removal:
- preferentially remove 14-hydroxycodeinone from the formed oxycodone salt

The claims do not require a specific solvent identity at the independent level. The dehydration is positioned as an outcome of the salt-forming conditions under acid. Removal is treated as a separate downstream purification step.

Claim 1: key structural elements

Element	Claim 1 language (functional paraphrase)	Claim coverage impact
Feed	oxycodone free base containing 8α,14-dihydroxy-7,8-dihydrocodeinone	Narrows to routes where this specific dihydroxy intermediate is present in the free base
Acid conversion	incubate with solvent + acid to convert free base to salt	Allows flexibility in solvent, acid identity is constrained later by dependent claims
Dehydration mechanism	acid catalyzed dehydration converts that intermediate to 14-hydroxycodeinone	Creates a mechanistic “hook” that ties impurity generation to process conditions
Purification	preferentially remove 14-hydroxycodeinone from the salt	Breadth depends on dependent claims (chromatography, hydrogenation, gels, etc.)

How broad are the claim categories? (Independent claim set and dependent fallbacks)

US 7,674,800 is claim-dense and uses two main tracks:

Process track: claims to a method of making oxycodone salts meeting impurity thresholds
Product track: claims to the resulting salt/composition (oxycodone hydrochloride and impurity ppm ranges)

Independent claims (high-level)

The specification you provided shows two independent structures:

Claim 1: process to prepare oxycodone salt substantially free of 14-hydroxycodeinone using dehydration then preferential removal
Claim 57: a parallel independent process claim that reduces 14-hydroxycodeinone to <25 ppm

Claim 30 and 76 are product “prepared according to” claims tied back to the processes.

What does the claim scope require on dehydration and impurity formation?

The dehydration requirement is central and appears repeatedly, not just once.

Essential impurity formation requirement

The oxycodone free base “having an 8α,14-dihydroxy-7,8-dihydrocodeinone component”
Under acid incubation, the process promotes conversion of that component to:
- 14-hydroxycodeinone

This means a manufacturing route that never forms 14-hydroxycodeinone during salt formation is not clearly within the same mechanistic framework, even if the final impurity level is low.

Mechanism in claim language

Claim 1 uses: “acid catalyzed dehydration consisting of conversion … to 14-hydroxycodeinone.”

Claim 57 uses the broader wording: “acid catalyzed dehydration whereby … is converted to 14-hydroxycodeinone.”

This is not phrased as “optional” impurity formation; it is tied to the conversion step.

What are the purification/removal embodiments (the big decision points for infringement risk)?

Claim 1 itself says “preferentially removing” without limiting technique. Dependent claims then supply multiple methods that can each function as independent infringement “routes” if used in the same overall sequence.

Enumerated purification techniques in the dependent claims

Dependent claims	Purification method	What is being “selectively removed”
Claim 7	Chromatographic separation	14-hydroxycodeinone is reduced by chromatographic separation
Claims 23-25 and 57/66-69 (repeated coverage)	Hydrogenation of the salt, converting 14-hydroxycodeinone to the salt form consistent with reduction	14-hydroxycodeinone is reduced by hydrogenation
Claims 26-29 and 70-72 (repeated coverage)	Substance preferentially removes 14-hydroxycodeinone, substance can be a gel, with pass-through or slurry	Preferential removal by an adsorption or binding medium

The design is consistent: even if a competitor avoids chromatography, they may still land inside if they do hydrogenation or use an analogous preferential-removal medium.

What process parameters are claimed (temperature, pH, acid equivalents, hydrogenation time)?

The dependent claims define multiple numeric “gates” that can narrow or capture specific commercial operating windows.

Acid strength and pH gates

Claim 3: pH about 2.5 or less
Claim 4: pH about 1.8 or less
Claim 5: pH about 1.5 or less
Claim 6: pH about 1 or less

These create an increasingly narrow ladder. If a process uses a pH higher than 2.5, it avoids at least those dependent-ladder limitations (but may still infringe claim 1 if claim 1 does not require the pH numeric range).

Temperature gates

Claim 2: heated to about 75°C
Claim 8: step (b) carried out at about 20°C
Claim 9: step (b) carried out between 40°C and 85°C

The dependent claims cover both cool and hot conditions, which reduces the chance that a competitor can step outside by selecting one typical temperature window.

Acid equivalents

Claim 13: acid amount greater than 1 molar equivalent vs oxycodone
Claim 15: for hydrochloric acid, greater than 1 molar equivalent
Claim 16-18: for hydrochloric acid, greater than about:
- 1.2 equivalents (Claim 16)
- 1.4 equivalents (Claim 17)
- 1.5 equivalents (Claim 18)

Again, these are dependent gates. The independent claim does not require hydrochloric acid or specific equivalents in the excerpt you provided.

Hydrogenation exposure

Hydrogenation appears in dependent claims as a critical reduction step, with multiple time windows.

Claim 10-12: at least about 4 hours, at least about 5 hours, and about 21 hours
Claim 25: between about 10 minutes and 36 hours
Claims 50-54: hydrogenation until impurity falls into specific ppm bands (see below)

This is a strong coverage area because it captures both short and long hydrogenation process philosophies.

What impurity specifications define the “substantially free” boundary?

The claims pin the target impurity to explicit ppm thresholds.

Lower-bound ppm thresholds in the product claims

A series of dependent product claims establish ceilings:

Claim 19-22: <25 ppm; <15 ppm; <10 ppm; <5 ppm
Claims 32-35: same ppm ceilings for oxycodone hydrochloride product claims
Claim 46: <15 ppm
Claim 73-75: <25 ppm; <10 ppm; <5 ppm
Claim 80: between 0.5 ppm and 25 ppm
Claim 55 and Claim 81: lower limit bands for 14-hydroxycodeinone:
- Claim 55: lower limit of 0.25, 0.5, 1, 2, or 5 ppm
- Claim 81: lower limit of 2 ppm or 5 ppm

Direct depiction of the “decrease by hydrogenation” design in Claim 38

Claim 38 includes a process history with an explicit “starting impurity high then reducing” structure:

Preparing oxycodone hydrochloride
Start with conditions where dehydration yields >100 ppm 14-hydroxycodeinone
Then hydrogenating until <25 ppm

This claim provides a clear infringement target for processes that: 1) intentionally drive dehydration under strong acid conditions, and 2) rely on hydrogenation as the reduction step.

How the claim set handles oxycodone salt identity (hydrochloride) and composition scope

Oxycodone salt and composition claims

Claim 30: oxycodone salt prepared according to Claim 1
Claim 31: oxycodone salt according to Claim 30 where salt is oxycodone hydrochloride
Claims 32-35: hydrochloride impurity ceilings
Claim 56: suitable for commercial oxycodone product
Claim 38-54, 46-55: more detailed composition/process-history claims focused on oxycodone hydrochloride and hydrogenation specifics
Claims 57-81: parallel process and product claims again tied to <25 ppm and specific lower/upper impurity bands

The presence of multiple “oxycodone hydrochloride” dependents means the strongest product coverage is for HCl salt, but process coverage could still apply outside HCl if claim 1 is asserted.

Is the claim scope driven more by starting impurity content or by the process steps?

It is step-driven, but the feed impurity content is still required.

Step-driven: acid dehydration conversion of the specific 8α,14-dihydroxy-7,8-dihydrocodeinone component to 14-hydroxycodeinone, then preferential removal.
Feed-linked: the free base must contain the 8α,14-dihydroxy-7,8-dihydrocodeinone component.

This matters because a competitor could try to argue that their free base does not contain that component, which would undermine the mechanistic basis for conversion to 14-hydroxycodeinone “as claimed.”

Patent landscape: what this patent likely blocks in the US market

Based on the structure of claims, the patent most directly blocks US manufacture of oxycodone salts that both: 1) form 14-hydroxycodeinone via acid-catalyzed dehydration during salt formation, and 2) then reduce it to low ppm via chromatography, hydrogenation, or preferential adsorption/removal.

Landscape map of “likely design-around space” (mechanistic vs operational)

Design axis	How US 7,674,800 frames it	Practical effect on infringement risk
Acid conditions	pH ≤ 2.5 (and tighter in dependents), acid equivalents >1, often HCl	Avoiding dehydration under these conditions can be a design-around, but final impurity control still must be low
Dehydration pathway	specifically tied to 8α,14-dihydroxy-7,8-dihydrocodeinone converting to 14-hydroxycodeinone	Routes that avoid this conversion or lack this component are the cleanest escape
Purification chemistry	hydrogenation, chromatography, preferential gel/adsorbent removal	Using other impurity-reduction methods can escape dependent claims, but claim 1’s broad “preferentially removing” keeps pressure
Impurity spec	<25 ppm (and lower bands) plus optional lower-limit ranges	If product specs land above thresholds, risk drops; if they land inside, risk increases

What is the claim fence around hydrogenation?

Hydrogenation is the most operationally specific capture: it is called out across multiple dependents and composition claims.

Hydrogenation hooks

Hydrogenation reagents can be:
- a hydrogenation catalyst and either:
- hydrogen or hydrogen transfer reagent (Claim 24)
Hydrogen donor examples (Claim 48):
- hydrogen gas, formic acid, indoline, cyclohexene, sodium borohydride, tetrahydroquinoline, 2,5-dihydrofuran, phosphoric acid

Hydrogenation conditions

Reflux (Claim 40)
Alcohol solvent selection (Claim 42):
- methanol, ethanol, or isopropanol
Recovery/crystallization (Claims 43-44)

This is valuable because it blocks multiple plausible industrial hydrogenation embodiments.

What do the “chromatographic separation” and “gel” dependents do to the fence?

They broaden the purification methods beyond hydrogenation.

Chromatography (Claim 7, Claim 66): captures process variants where impurity is separated without chemistry conversion.
Gel/adsorbent preferential removal (Claims 26-29, 70-72): captures purification media-based removal.

If a competitor uses a preferential adsorption medium, the patent can attach even without hydrogenation chemistry, as long as:

the sequence includes acid dehydration conversion of the specific component to 14-hydroxycodeinone, and
the medium preferentially removes 14-hydroxycodeinone relative to oxycodone salt.

How claim 38 changes the infringement picture

Claim 38 includes an explicit “start high impurity” structure:

In producing oxycodone hydrochloride:
- the acid-catalyzed dehydration conditions produce >100 ppm 14-hydroxycodeinone
Hydrogenation converts that to:
- <25 ppm (and in dependents to <15, <10, <5)

This is important because it makes the method history measurable and ties the reduction step directly to impurity trajectory. If a competitor’s process never produces >100 ppm at the intermediate stage, claim 38’s particular structure may not read, even if they reach <25 ppm in final product.

Where US 7,674,800 likely sits relative to other oxycodone impurity patents

Your prompt asks for a landscape analysis of claims and the patent landscape, but it does not include:

the patent bibliographic record (assignee, priority dates, related prosecution history),
forward citations,
family members,
continuation filings,
or any other patent numbers for US 7,674,800.

Without those, no complete, accurate US landscape mapping (other than the claim-internal landscape described above) can be produced.

Key claim takeaways for enforcement and freedom-to-operate

Mechanistic sequence is required: acid dehydration during salt formation converts a specific dihydroxy component to 14-hydroxycodeinone, followed by preferential removal.
Purification is multi-modal: claims cover chromatography, hydrogenation, and preferential gel/medium removal.
Numeric boundaries are extensive:
- pH down to ≤1,
- temperature windows from 20°C to 85°C,
- hydrogenation time from 10 minutes to 36 hours,
- impurity spec ceilings down to <5 ppm.
Oxycodone hydrochloride is a primary target in the product claims and detailed composition claims.
Intermediate impurity trajectory is a captured feature in Claim 38 (dehydration yields >100 ppm, then hydrogenation reduces to low ppm).

Key Takeaways

US 7,674,800 claims an acid-catalyzed dehydration step during oxycodone salt formation that converts an 8α,14-dihydroxy-7,8-dihydrocodeinone component to 14-hydroxycodeinone, followed by preferential removal to reach <25 ppm (and often much lower) in the final salt.
The patent’s enforcement leverage comes from three purification pillars embedded across dependent claims: chromatography, hydrogenation, and preferential removal via substances such as gels.
The claim set is operationally specific via pH, acid equivalents, temperature, hydrogenation time, and impurity ppm ranges, with strong coverage around oxycodone hydrochloride.
A meaningful design-around must address the mechanistic feed-to-impurity conversion (presence/formation of 14-hydroxycodeinone during salt formation) or use a purification route outside the claimed “preferential removal” embodiments while also meeting the low ppm specifications.

FAQs

What impurity does US 7,674,800 control?
14-hydroxycodeinone, with final specifications such as <25 ppm, <15 ppm, <10 ppm, and <5 ppm.
What must the oxycodone free base contain for claim 1?
An 8α,14-dihydroxy-7,8-dihydrocodeinone component that is converted under acid dehydration to 14-hydroxycodeinone.
Is hydrogenation required to infringe?
Not for all claims. Hydrogenation is covered in multiple dependents and a detailed composition history (e.g., Claim 38), but the broader claim set also includes chromatography and preferential removal using media such as gels.
What pH range is explicitly claimed?
Dependent claims cover pH ≤2.5, and also tighter limits down to pH ≤1.
Does the patent focus on oxycodone hydrochloride specifically?
The strongest product and composition dependents are for oxycodone hydrochloride, including solvent/reflux/hydrogen donor specifics, though claim 1 is written around “an acid” in the excerpt you provided.

References (APA)

No external sources were provided in the prompt; no citations can be generated from the information supplied.

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
Austria	E501150	⤷ 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