US Patent 6,676,967: What Is Actually Claimed and Where the Patent Fence Sits
United States Patent 6,676,967 claims a specific dosing and formulation performance method for intermediate-release oral nicotinic acid to (i) reduce flushing while (ii) effectively treating a lipidemic disorder, and to do so without treatment-limiting hepatotoxicity and without treatment-limiting elevations in uric acid or glucose (or both) that would force discontinuation by the patient. The claim scope is driven less by “use of nicotinic acid” and more by tight dissolution/disintegration-style performance criteria, timing (once-daily evening/night), and dose amount ranges (including a high-strength variant).
What do the independent claims require? (Claim 1 and Claim 16)
Claim 1 (core scope)
Claim 1 is a method of treatment comprising the following required elements (all must be met):
-
Patient condition
- “an individual being treated for a lipidemic disorder”
-
Therapeutic objective
- “reducing flushing”
- “effectively treating the lipidemic disorder”
-
Regimen and route
- “intermediate release nicotinic acid formulation”
- “suitable for oral administration”
- “once-a-day as a single dose”
- orally administer “an effective amount” once per day as a single dose
-
Safety/discontinuation constraint
- the regimen/formulation is used “without causing treatment-limiting hepatotoxicity”
- also “without causing treatment-limiting elevations in uric acid or glucose levels or both”
- and the elevations must not reach a level “which would require use…to be discontinued”
-
Dissolution curve similarity fit factor
- “intermediate release nicotinic acid formulation having a dissolution curve similarity fit factor F2 of at least about 79”
-
In vitro dissolution profile definition
- apparatus: “type I dissolution apparatus (basket) according to U.S. Pharmacopeia XXII”
- medium: “about 37° C. in deionized water”
- rpm: “about 100 rpm”
- release milestones:
- < 15% released after 1 hour
- 15% to 30% after 3 hours
- 30% to 45% after 6 hours
- 40% to 60% after 9 hours
- 50% to 75% after 12 hours
- ≥ 75% after 20 hours
Interpretive point for enforcement: this independent claim is effectively a performance claim. Even if a product contains nicotinic acid and is dosed once daily, it will not meet Claim 1 unless its in vitro dissolution in the specified system matches the milestone windows and it achieves an F2 similarity of at least ~79.
Claim 16 (high-strength and different F2 threshold)
Claim 16 is structurally the same method, but with a materially different formulation gate:
- Same patient condition, objectives, once-daily oral single-dose regimen
- Same safety/discontinuation constraint for:
- hepatotoxicity
- uric acid elevations and/or glucose elevations reaching discontinuation threshold
- Same dissolution window shape:
- <15% at 1 hour
- 15% to 30% at 3 hours
- 30% to 45% at 6 hours
- 40% to 60% at 9 hours
- 50% to 75% at 12 hours
- ≥75% at 20 hours
- Different dissociation gate:
- “intermediate release nicotinic acid formulation containing at least about 1000 mg of nicotinic acid”
- Different F2 gate:
- “dissolution curve similarity fit factor F2 of at least about 44”
Enforcement implication: Claim 16 captures very high strength nicotinic acid intermediates (≥1000 mg) with a looser dissolution-profile similarity threshold (F2 ≥ 44) while keeping the same milestone ranges. Claim 1 is narrower on F2 (≥79) but does not state a ≥1000 mg minimum.
How dependent claims narrow the fence (claims 2-15 and 17-27)
Even broader protection inside the same dissolution “box”
Many dependent claims lock in either “about 100% release at 20 hours,” “tablet,” and specific strength options, or timing (evening/night).
“Approximately 100% release at 20 hours”
- Claim 2: Claim 1 where “approximately 100% of the nicotinic acid is released after about 20 hours in the apparatus.”
- Claim 6: same narrowing relative to Claim 5
- Claim 10: same narrowing relative to Claim 9
- Claim 17: same narrowing relative to Claim 16
- Claim 20/23: same narrowing relative to Claims 19/22
This tightens product conformity at the terminal point without changing earlier milestone ranges.
Dosage form narrowing to tablet
- Claim 3 / 7 / 11: Claim 1 derivatives where “formulation is a tablet”
- Claim 18 / 21 / 24: Claim 16 derivatives where “formulation is a tablet”
Tablet strength options
For the Claim 1 family:
- Claim 4: tablet contains nicotinic acid of approximately 375 mg, 500 mg, or 750 mg
- Claims 8, 12 replicate the same strength set tied to other dependent dependents.
For the Claim 16 family:
- The claims you provided do not explicitly list tablet strengths, but Claim 16 requires at least about 1000 mg of nicotinic acid.
Expanded numeric dissolution windows
- Claim 5: Claim 1 where dissolution is specified by tighter ranges:
- at 1 hour: 9.6% to 13.8%
- at 3 hours: 21.2% to 27.8%
- at 6 hours: 35.1% to 44.2%
- at 9 hours: 45.6% to 58.5%
- at 12 hours: 56.2% to 72%
- at 20 hours: ≥75%
- Claim 9: same as Claim 5 but dependent on Claim 1 through the tablet chain
- Claim 13: same structure you provided (through the tablet chain)
- Claim 19 and Claims 22/… in the Claim 16 family repeat the same tighter dissolution windows as above
This means the patent has two dissolution layers:
- a broad milestone band in independent claims (Claim 1/16)
- a tight sub-band in intermediate dependent claims (Claims 5/9/13/19/22 etc.)
Dosing time narrowing (evening/night)
- Claim 13: single dose administered during the “evening or at night”
- Claim 14: between 6 pm and 12 am
- Claim 15: between 8 pm and 10 pm
- Claims 25-27: same for the Claim 16 chain
Practical scope note: timing is an additional method step. A generic product that meets dissolution and dose/safety constraints but is taken outside the evening/night windows will avoid these dependent claims while still potentially implicating the independent claims unless a court construes timing as required for the independent claim (the independent claims do not include time-of-day).
Scope summary: what must a product do to infringe?
Infringement for Claim 1 (method) requires all of the following
- oral intermediate-release nicotinic acid, once daily, single dose
- prevents or avoids treatment-limiting hepatotoxicity
- avoids treatment-limiting uric acid/glucose elevations
- dissolution in USP XXII type I basket at 37°C 100 rpm in deionized water:
- <15% @1h
- 15-30% @3h
- 30-45% @6h
- 40-60% @9h
- 50-75% @12h
- ≥75% @20h
- F2 ≥ ~79
Infringement for Claim 16 requires all of the following
- same method concept and dissolution milestones as above
- contains ≥1000 mg nicotinic acid
- F2 ≥ ~44
- once-daily oral single-dose regimen
- same safety/discontinuation constraints
Tablet and strength dependence
- Tablet-only: Claim 3/7/11/18/21/24
- Specific strengths only appear in your provided text for the Claim 1 family:
- 375 mg / 500 mg / 750 mg (Claims 4/8/12)
Dissolution performance: the patent’s technical “handle”
Key parameters locked by claim language
- apparatus: USP XXII type I basket
- medium: deionized water
- temperature: 37°C
- rotation speed: 100 rpm
- sampling times: ~1h, 3h, 6h, 9h, 12h, 20h
- release acceptance bands:
- broad bands in independent claims
- tighter sub-bands in dependent claims
- profile similarity:
- F2 threshold
- Claim 1: ≥79
- Claim 16: ≥44
Milestone band comparison (independent)
| Time point |
Claim 1 / Claim 16 minimum-maximum release window |
| ~1 h |
<15% |
| ~3 h |
15% to 30% |
| ~6 h |
30% to 45% |
| ~9 h |
40% to 60% |
| ~12 h |
50% to 75% |
| ~20 h |
≥75% |
Tight dissolution window example (dependent claims)
| Time point |
Tight ranges used in Claims 5/9/19/22 (as provided) |
| ~1 h |
9.6% to 13.8% |
| ~3 h |
21.2% to 27.8% |
| ~6 h |
35.1% to 44.2% |
| ~9 h |
45.6% to 58.5% |
| ~12 h |
56.2% to 72% |
| ~20 h |
≥75% |
Patent landscape: what this claim set implies for competitors
Your text provides the claim set, but not the assignee, filing dates, specification content, priority chain, family members, or the exact Orange Book listing(s). Without those, a complete and accurate US landscape mapping (related US patents, continuations, continuation-in-part boundaries, terminal disclaimers, overlaps with known niacin ER products, and whether they were FDA-listed) cannot be produced.
What can be concluded from the claim language alone
This patent’s competitive impact clusters into two technical infringement risks for competitors:
-
Performance-to-spec risk
- A competitor can design around typical “intermediate-release” language, but the claim’s dissolution windows and F2 thresholds create a spec-driven infringement surface.
- If the product’s dissolution curve similarity and release milestones match the specified in vitro profile, method claims are vulnerable even if the competitor labels a different “intermediate” technology.
-
Method-of-use risk
- The method includes a clinical safety framing (no discontinuation due to hepatotoxicity and uric acid/glucose elevation).
- Competitors cannot easily “label around” this if the product’s real-world or clinical evidence demonstrates the safety profile meets the “treatment-limiting” boundary used in the claim.
Design-around directions implied by the claim set
- Lower or alter dissolution timing such that any one milestone band is missed (for example, shifting release outside 40-60% at 9 hours).
- Reduce dissolution curve similarity (F2) below the threshold (≥79 for Claim 1 and ≥44 for Claim 16).
- Use a different dose strength that avoids the tablet strength-dependent claims in the Claim 1 family (375/500/750 mg), while also avoiding the ≥1000 mg gate in Claim 16.
- Avoid the dependent “evening/night” timing restrictions (6 pm to 12 am or 8 pm to 10 pm) if the strategy is to evade dependent claims while still evaluating independent-claim exposure.
Key takeaways
- US 6,676,967 is a spec-driven method patent for once-daily intermediate-release oral nicotinic acid that must both reduce flushing and avoid discontinuation-limiting hepatotoxicity and uric acid/glucose elevations.
- F2 threshold and USP dissolution milestones are the central scope determinants:
- Claim 1 requires F2 ≥ ~79 plus the dissolution milestone windows.
- Claim 16 requires ≥1000 mg nicotinic acid plus the same milestone windows but only F2 ≥ ~44.
- Dependent claims narrow further by tablet-only, specific tablet strengths (375/500/750 mg) for the Claim 1 chain, tight dissolution sub-ranges, and time-of-dose (evening/night).
- The enforceable boundary sits at the intersection of patient outcome framing (no discontinuation) and in vitro dissolution performance under USP XXII basket conditions.
FAQs
1) Does the patent cover any intermediate-release nicotinic acid product?
No. It is limited to oral once-daily single-dose nicotinic acid formulations that meet specified dissolution milestone windows under USP XXII type I basket conditions and satisfy F2 thresholds (Claim 1: ≥79; Claim 16: ≥44).
2) What makes Claim 16 materially different from Claim 1?
Claim 16 adds a formulation-content gate of at least about 1000 mg nicotinic acid and uses a lower F2 threshold (≥44) while retaining the same milestone windows.
3) Are the dissolution requirements the same across dependent and independent claims?
The independent claims define broad milestone bands; several dependent claims add tighter numeric ranges at each time point and also include “approximately 100%” released at ~20 hours.
4) Is dosing time-of-day part of every claim?
No. The evening/night dosing window appears in dependent claims (for example 6 pm to 12 am; 8 pm to 10 pm). The independent claims you provided do not require a specific time-of-day.
5) Can a competitor avoid the patent by changing dose strength?
It can avoid the strength-dependent dependent claims tied to about 375/500/750 mg, but independent-claim exposure still depends on meeting the dissolution/F2 and method safety constraints.
References (APA)
[1] United States Patent 6,676,967. (Claims text provided in prompt).
