US Patent 6,054,430: Scope, Claim Anatomy, and US Landscape

US Patent 6,054,430 is a US-origin patent that claims a process to generate Copolymer-1 (and an intermediate) with a defined molecular-weight distribution. The invention’s legal hook is the bounded MW window (2 to 20 kDa) captured as “over 75% molar fraction”, coupled to a two-step deprotection workflow: (i) HBr cleavage to produce a trifluoroacetyl copolymer-1, then (ii) aqueous piperidine treatment to yield copolymer-1. Dependent claims narrow the time and temperature of the HBr step.

What exactly does the patent claim? (Independent claim 1)

Claim 1 reads as a process claim with three connected elements:

1) Product definition via a distribution metric

It requires Copolymer-1 “having over 75% of its molar fraction within”:

About 2 kDa to about 20 kDa

This is not a simple average MW limitation. The claim is drafted as a distribution requirement, measured as molar fraction inside the MW window.

Practical scope impact: A competitor does not need to match a single MW. It must match the fractional distribution. That can be decisive for infringement because it moves the dispute into analytical characterization (e.g., gel permeation/size exclusion or other fractionation methods) rather than only bulk MW.

2) Intermediate and conversion steps

The claimed process has two conversion steps:

Step A:
“reacting protected copolymer-1 with hydrobromic acid to form trifluoroacetyl copolymer-1”
where the intermediate also has the same distribution requirement:

intermediate: “having over 75% of its molar fraction within … about 2 kDa to about 20 kDa”

Step B:
“treating said trifluoroacetyl copolymer-1 with aqueous piperidine to form copolymer-1”
again retaining the same distribution requirement.

3) Process control by “test reaction predetermined”

Claim 1 introduces a process-control concept:

reaction with HBr occurs for a time and temperature predetermined by test reaction.

Legal scope impact: This language is broad in that it does not lock the time or temperature, but it still demands a methodology constraint. A defendant can argue non-infringement if they use different test criteria, different process control targets, or if the resulting distribution fails the “over 75%” threshold.

How do dependent claims narrow scope (Claims 2-3 and 5-6)?

Dependent claims 2 and 3: HBr conditions

Claim 2: HBr reaction about 10 to 50 hours at about 20 to 28°C
Claim 3: HBr reaction about 17 hours at about 26°C

These convert the “predetermined by test reaction” concept into fixed points or ranges.

Infringement effect: A process that uses HBr outside these bounds would still potentially fall under claim 1 (if “predetermined by test reaction” is met) but would miss claims 2 or 3.

Dependent claims 5 and 6: Intermediate trifluoroacetyl conditions

Claim 5: trifluoroacetyl copolymer-1 produced by HBr reaction about 10 to 50 hours at about 20 to 28°C
Claim 6: HBr reaction about 17 hours at about 26°C

These are essentially mirror limitations tied to claim 4’s intermediate product-by-process framing.

What does claim 4 add? (Intermediate “produced by” claim)

Claim 4 claims a product defined as:

“Trifluoroacetyl copolymer-1 having over 75% of its molar fraction within about 2 kDa to about 20 kDa”
and it is “produced by a process comprising” the HBr reaction step “for a time and at a temperature predetermined by test reaction.”

Key difference from claim 1: Claim 4 does not require the aqueous piperidine treatment. It locks the intermediate product and uses product-by-process language tied to how it is produced.

Landscape implication: If a third party makes the intermediate but does not convert it to final copolymer-1, claim 4 can still be asserted, depending on how clearly “produced by” can be proven and whether the MW distribution matches.

Claim coverage in functional blocks (what must be present for infringement)

A clean infringement map for US 6,054,430 breaks into four technical gates:

Starting material: “protected copolymer-1”
HBr deprotection step: HBr to form trifluoroacetyl copolymer-1
Aqueous piperidine step (for claim 1 only): trifluoroacetyl to copolymer-1
MW distribution requirement: all relevant copolymer materials must have >75% molar fraction within ~2-20 kDa

If any one gate fails, infringement risk drops substantially for that claim.

What is the likely competitive “design-around” space?

Given the claim architecture, the strongest design-around vectors are:

Change the MW distribution so the copolymer does not meet “over 75% molar fraction within 2-20 kDa.”
Use a different deprotection system than HBr, or avoid creating the specifically labeled intermediate sequence leading to the trifluoroacetyl copolymer-1 under these conditions.
Avoid aqueous piperidine conversion (claim 1) or avoid formation of the specified intermediate distribution (claim 4).
Shift HBr time/temperature outside dependent ranges (10-50 hours; 20-28°C; or 17 hours at 26°C). Even if claim 1 might still apply under “predetermined by test reaction,” narrowing time and temperature can reduce the credibility of equivalence arguments depending on how the “predetermined” test is documented and defended.

The MW-distribution requirement is the most measurable and thus the most litigated likely axis. It also creates potential leverage for both claim construction and expert analysis.

Patent landscape: what can be inferred from the claim structure

1) Positioning within broader Copolymer-1 IP

Copolymer-1 processes with defined MW bands and specific chemical steps are characteristic of a patent family where the IP perimeter is carved around:

a defined MW fraction specification for therapeutic or formulation performance, and
defined chemistry steps for preparing and converting protected forms.

Given this is a US patent and it is claiming both intermediate and final product conversion workflows, the landscape is likely to include:

earlier patents on preparation of protected copolymer-1 and protection/deprotection chemistry,
later patents on controlling molecular-weight fraction distributions for efficacy or tolerability, and
process patents tied to conversion steps (including deprotection chemistry and post-processing conditions).

2) How the claim reads relative to “method” and “product-by-process”

Claim 1 is a classic method of preparation with a final product distribution limitation.
Claim 4 is a product-by-process claim on the intermediate.

This split matters in enforcement strategy:

a party controlling intermediate production can face claim 4 exposure even if final conversion is performed by another unit.
a party controlling final product conversion faces claim 1.

3) Overlap pressure points for future filings

The “over 75% molar fraction in 2-20 kDa” is a narrow characterization standard that other assignees may attempt to avoid by:

using different cutoff thresholds (e.g., 60% or 80%),
shifting the MW window (e.g., 1-15 kDa or 3-25 kDa),
or using different distribution metrics (e.g., weight fraction instead of molar fraction, depending on how claims are interpreted).

Claim language that uses both molar fraction and MW bounds often drives follow-on filings around those measurement choices.

Scope summary table

Claim	Claimed subject	Chemical steps required	MW distribution requirement	Narrowing parameters
1	Process to make copolymer-1	protected copolymer-1 + HBr → trifluoroacetyl intermediate; then + aqueous piperidine	final copolymer-1: >75% molar fraction in ~2-20 kDa (also required for intermediate)	HBr time/temp are predetermined by test reaction (no fixed values in claim 1)
2	Same process as claim 1	same steps	same MW requirement	HBr: ~10-50 hours, ~20-28°C
3	Same process as claim 1	same steps	same MW requirement	HBr: ~17 hours, ~26°C
4	Trifluoroacetyl copolymer-1 intermediate	protected copolymer-1 + HBr → trifluoroacetyl intermediate	intermediate: >75% molar fraction in ~2-20 kDa	HBr time/temp: “predetermined by test reaction”
5	Same as claim 4	same HBr step	same MW requirement	HBr: ~10-50 hours, ~20-28°C
6	Same as claim 4	same HBr step	same MW requirement	HBr: ~17 hours, ~26°C

How strong is claim coverage vs typical competitor process variations?

If a competitor changes only HBr operating conditions

They may avoid claims 2, 3, 5, 6 if outside the dependent ranges.
They may still fall within claim 1/4 if their time/temp are still “predetermined by test reaction” and the MW distribution matches.

If a competitor changes analytical distribution

If they target a different fraction threshold or MW window, they can potentially avoid all claims because “over 75% molar fraction within about 2-20 kDa” is common to all of them.
This is the most plausible high-impact design-around.

If a competitor bypasses the trifluoroacetyl intermediate or avoids piperidine

Claim 1 requires the trifluoroacetyl intermediate plus piperidine conversion.
A process that uses alternative conversion chemistry to reach copolymer-1 without forming the trifluoroacetyl intermediate (or without producing it under claimed distribution conditions) reduces claim 1 risk sharply.
Claim 4 still requires formation of the trifluoroacetyl intermediate under the MW constraint, so bypassing the intermediate reduces exposure.

Key Takeaways

US 6,054,430 is built around MW distribution: the decisive limiter is “over 75% of molar fraction” in the ~2 to ~20 kDa** range.
Claim 1 is a full process: protected copolymer-1 + HBr to the trifluoroacetyl intermediate, then aqueous piperidine to copolymer-1, with the MW distribution requirement applied to both the intermediate and the final product.
Claims 2-3 and 5-6 narrow HBr conditions: 10-50 hours at 20-28°C and specifically 17 hours at 26°C.
Claim 4 targets the intermediate: trifluoroacetyl copolymer-1 produced by an HBr step under “test reaction predetermined” time/temp and the same MW distribution standard.
The likely enforcement and design-around battleground is MW distribution proof (molar fraction in the specified band), plus whether a competitor’s chemistry produces the trifluoroacetyl intermediate and uses aqueous piperidine where required.

FAQs

1) Is US 6,054,430 mainly a composition claim or a process claim?
It is primarily a process patent (claim 1) plus an intermediate product-by-process claim (claim 4).

2) What is the single most important quantitative limitation?
The requirement that the relevant copolymer material has “over 75% of its molar fraction” within about 2 kDa to about 20 kDa.

3) Do dependent claims fully replace the “predetermined by test reaction” limitation?
Dependent claims narrow the HBr step to specified time and temperature ranges or points, but claim 1 still uses the broader “test reaction predetermined” framing.

4) Can a company be exposed if it stops at the trifluoroacetyl intermediate?
Yes. Claim 4 covers trifluoroacetyl copolymer-1 made by the HBr step under the claimed MW distribution.

5) What is the most straightforward design-around approach?
Shift away from the claimed MW distribution (molar fraction inside ~2-20 kDa above the 75% threshold) or avoid the claimed chemistry sequence (HBr to the specified intermediate and, for claim 1, conversion with aqueous piperidine).

References (APA)

[1] US Patent 6,054,430. (n.d.). Claims text as provided in user prompt.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0762888	⤷ Start Trial	90987	Luxembourg	⤷ Start Trial
European Patent Office	0762888	⤷ Start Trial	C300096	Netherlands	⤷ Start Trial
European Patent Office	0762888	⤷ Start Trial	C300251	Netherlands	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,054,430

Summary for Patent: 6,054,430