United States RE30577 Patent Analysis: Scope, Claim Coverage, and US Patent Landscape for Ether Salts

RE30577 is a US reissue patent (reissue “RE” series) whose claim set is narrowly framed around (i) ethers of a defined structural formula (“ether of claim 1” and “An ether having the formula ##STR34##”) and (ii) pharmaceutically acceptable acid addition salts, with claim-by-claim dependent coverage tied to specific amine substituents (A), alkyl substituent on the ether (R), and aromatic groups (Ar, Ar1), plus only two explicit salt types (hydrochloride and fumarate) in the dependent claim layer you provided.

Because the full underlying “claim 1” structure is not included in the text you supplied, the analysis below focuses on what can be concluded directly from the dependent claims and the existence/scope signal embedded in RE30577’s claim architecture: breadth is driven by whether “claim 1” has a broad Markush or open substitution ranges, while RE30577 itself narrows salts and enumerates specific substituent combinations through dependent claims.

Immediate scope answer (from the claims provided)

Core subject matter: an ether compound described by a formula referenced as ##STR34##, and its pharmaceutically acceptable acid addition salts.
Salt scope: hydrochloride and acid fumarate are explicitly covered; dependent claims also list combinations matching specific ether variants.
Variant scope (through dependent claims 2–6): multiple substitutions are explicitly claimed for the ether scaffold, including:
- A = pyrrolidino, R = isobutyl, Ar = phenyl, Ar1 = phenyl (hydrochloride)
- A = pyrrolidino, R = isobutyl, Ar = phenyl, Ar1 = 2-pyridyl (fumarate)
- A = diethylamino, R = isobutyl, Ar = phenyl, Ar1 = phenyl (fumarate)
- A = morpholino, R = isobutyl, Ar = phenyl, Ar1 = phenyl (fumarate)
- A = piperidyl, R = benzyl, Ar = phenyl, Ar1 = phenyl (hydrochloride)

What is the claim scope of US patent RE30577 (ether salts), and how broad are the substitution options?

What the independent coverage implies (claims 7–8)

Claim 7: “An ether having the formula ##STR34## and pharmaceutically acceptable acid addition salts thereof.”
- This is an independent “formula to salts” claim. It typically covers the ether in essentially the specific formula definition used in the patent, with salts captured by “pharmaceutically acceptable acid addition salts.”
Claim 8: “wherein the acid addition salt is the hydrochloride or the acid fumarate.”
- This is an independent salt-type limitation layer (hydrochloride or fumarate) tied to claim 7.

Dependent claims 2–6 show how specific salts are paired with specific variants

Your excerpt indicates a dependency from a broader “ether of claim 1.” The dependent claim list indicates:

For A = pyrrolidino / R = isobutyl / Ar = phenyl / Ar1 = phenyl, the claimed salt is hydrochloride (claim 2).
For A = pyrrolidino / R = isobutyl / Ar = phenyl / Ar1 = 2-pyridyl, the claimed salt is acid fumarate (claim 3).
For A = diethylamino / R = isobutyl / Ar = phenyl / Ar1 = phenyl, the claimed salt is acid fumarate (claim 4).
For A = morpholino / R = isobutyl / Ar = phenyl / Ar1 = phenyl, the claimed salt is acid fumarate (claim 5).
For A = piperidyl / R = benzyl / Ar = phenyl / Ar1 = phenyl, the claimed salt is hydrochloride (claim 6).

How broad is “pharmaceutically acceptable acid addition salts” in claim 7?

Claim 7 uses a functional acceptability phrase that usually captures salts with a typical set of pharma acids (e.g., HCl, fumaric, maleic, citric, etc.) if they are “pharmaceutically acceptable” and supported by the specification.
Claim 8 then narrows explicitly to hydrochloride and acid fumarate.
Practically, for freedom-to-operate analysis, the broadness comes from:
1. whether the formula ##STR34## is itself narrow or Markush;
2. whether the specification enables other acid salts beyond HCl and fumarate;
3. whether prosecution history estoppel exists from the reissue (not provided here).

What exact ether structures (A, R, Ar, Ar1) are covered under RE30577 dependent claims 2–6?

Dependent claim coverage table (based on your claim text)

Dependent claim	A	R	Ar	Ar1	Salt explicitly claimed
2	pyrrolidino	isobutyl	phenyl	phenyl	hydrochloride
3	pyrrolidino	isobutyl	phenyl	2-pyridyl	acid fumarate
4	diethylamino	isobutyl	phenyl	phenyl	acid fumarate
5	morpholino	isobutyl	phenyl	phenyl	acid fumarate
6	piperidyl	benzyl	phenyl	phenyl	hydrochloride

Substitution pattern takeaways for claim interpretation

A group scope is at least plural and enumerated: pyrrolidino, diethylamino, morpholino, piperidyl.
R group scope is at least two types: isobutyl and benzyl.
Aromatic substitution is largely anchored:
- Most variants use Ar = phenyl.
- Ar1 = phenyl dominates; the only explicitly different Ar1 is 2-pyridyl in claim 3.

This pattern suggests claim drafting aimed to cover multiple basic amine ether analogs and their salt forms, with at least one heteroaryl (2-pyridyl) substitution carved out.

Which salt forms are protected by RE30577, and how does claim 8 limit the salt types?

Direct salt list from claims provided

Hydrochloride is explicitly claimed:
- In dependent claims 2 and 6
- As a permitted salt in claim 8
Acid fumarate is explicitly claimed:
- In dependent claims 3, 4, and 5
- As a permitted salt in claim 8

Practical protection map: generic or salt-change risk

If a competitor markets:

the same ether base (as defined by ##STR34##) but as:
- HCl: directly within claim 8 and within at least some dependent claims.
- fumarate: directly within claim 8 and within at least some dependent claims.
a different salt (e.g., maleate, citrate): claim 7’s “pharmaceutically acceptable acid addition salts” creates risk, but the strength depends on whether other salts are supported/enabled and whether claim 8 was used to secure narrower coverage.

How many patent claims in RE30577 cover the ether salts, and what does the claim architecture indicate about enforceable coverage?

From the excerpt you provided:

You have dependent claims 2–6 focused on enumerated substituent sets and specific salts.
You have claim 7 for an ether formula plus “pharmaceutically acceptable acid addition salts.”
You have claim 8 restricting acid salts to hydrochloride or acid fumarate.

Claim architecture signal

The independent “formula + salts” claim (claim 7) suggests enforcement could proceed on:
1. presence of the accused ether matching the ##STR34## formula; and
2. whether the product salt is an “acid addition salt” and “pharmaceutically acceptable.”
The independent “salt-type” claim (claim 8) gives an enforcement hook that does not require proving acceptability of other salts beyond HCl/fumarate.

What patent landscape surrounds US RE30577: reissue implications, typical competing estates, and likely blocking positions?

Reissue (“RE”) impact on landscape

A reissue patent often indicates at least one of:

a prior patent’s claims were corrected or broadened/narrowed through reissue practice;
patent term and priority remain tethered to the original non-reissue filing history (not provided here);
the reissue can consolidate claim scope into a refined set.

Landscape patterns for ether hydrochloride / fumarate protection

For basic amine ethers with salt-specific coverage, common nearby IP includes:

compound (free base) claims on the ether itself (or broader analog ranges);
salt claims (HCl, fumarate, maleate, etc.);
method-of-use claims (therapeutic indication, dosage regimen);
process/manufacturing claims for the ether or for preparing particular salts.

Given only the claim excerpt, you have direct visibility on salt and ether formula coverage. The broader landscape (methods, manufacturing, non-salt claims) cannot be enumerated accurately without the full patent record.

When does RE30577 lose exclusivity, and what does reissue do to expiration timing?

No expiration dates, priority dates, or underlying non-reissue patent number are present in your excerpt. Without those, a legally actionable exclusivity/timing schedule cannot be produced.

What generic entry risks exist for hydrochloride and fumarate versions covered by RE30577?

Risk framing tied to claim 8 (most direct)

If a generic applicant or licensee prepares a product that is:

the ether matching ##STR34##, and
formulated as hydrochloride or acid fumarate,

then claim 8 is the cleanest infringement path based solely on your provided text.

Risk framing tied to dependent claims 2–6 (variant-specific)

Even if claim 7’s formula coverage is disputed, dependent claims 2–6 provide additional guardrails for enumerated combinations:

HCl risk is concentrated in the pyrrolidino/isobutyl/phenyl/phenyl and piperidyl/benzyl/phenyl/phenyl variants (claims 2 and 6).
Fumarate risk is concentrated across the pyrrolidino/isobutyl/phenyl/2-pyridyl, diethylamino/isobutyl/phenyl/phenyl, and morpholino/isobutyl/phenyl/phenyl variants (claims 3–5).

What formulations are protected by RE30577 (salt vs. free base), and what dosage forms are implicated?

Your excerpt is salt-chemical and formula-chemical only; it does not specify dosage forms (tablet, capsule, solution) or manufacturing methods.

So the protected formulations, as evidenced by the claim text, are:

the ether free base implied by formula ##STR34## (claim 7), and
acid addition salt forms, especially:
- hydrochloride
- acid fumarate (claim 8)

Dosage forms and route-of-administration coverage cannot be derived from the claim excerpt.

What does RE30577’s claim language mean for regulatory filing strategy (ANDA vs. 505(b)(2))?

No FDA regulatory history, Orange Book listings, or reference product association is present in your excerpt.

So the only decision-relevant conclusion available from the text is that regulatory strategy must align with:

the claimed ether structure (##STR34##), and
the claimed salt form (HCl/fumarate in claim 8; broader acid addition salts in claim 7).

Key Takeaways

RE30577 claim coverage you provided is centered on a defined ether formula (##STR34##) and pharmaceutically acceptable acid addition salts (claim 7).
The most enforceable salt-specific coverage is hydrochloride and acid fumarate (claim 8), reinforced by dependent claims 2–6.
Dependent claims enumerate multiple ether variants using A (pyrrolidino, diethylamino, morpholino, piperidyl), R (isobutyl or benzyl), and aromatics (Ar = phenyl; Ar1 = phenyl or 2-pyridyl) with explicit salt selections.
Without the full underlying claim 1 formula, priority data, and full bibliographic record, the landscape cannot be completed (expiration, adjacent patents, Orange Book status, Paragraph IV scenarios).

FAQs

Does RE30577 cover only hydrochloride and fumarate, or other acid salts too?
Claim 7 covers “pharmaceutically acceptable acid addition salts,” while claim 8 explicitly limits to hydrochloride or acid fumarate.
Which ether variants in RE30577 are tied to hydrochloride salts?
The excerpt ties hydrochloride to (i) A = pyrrolidino, R = isobutyl, Ar = phenyl, Ar1 = phenyl and (ii) A = piperidyl, R = benzyl, Ar = phenyl, Ar1 = phenyl.
Which ether variants in RE30577 are tied to acid fumarate salts?
The excerpt ties acid fumarate to (i) A = pyrrolidino, R = isobutyl, Ar = phenyl, Ar1 = 2-pyridyl; (ii) A = diethylamino, R = isobutyl, Ar = phenyl, Ar1 = phenyl; and (iii) A = morpholino, R = isobutyl, Ar = phenyl, Ar1 = phenyl.
Can a generic avoid RE30577 by switching from fumarate to maleate?
Based on the claim excerpt, claim 8 would not cover maleate, but claim 7 may still capture other “pharmaceutically acceptable acid addition salts” if the ether matches the formula.
Is RE30577 limited to specific dosage forms or administration routes?
The provided claims are chemical (ether + salts) and do not specify dosage forms or routes.

References

Provided claim text for US patent RE30577 (claims 2–8 excerpt).

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
France	72.07647	Mar 6, 1972

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Belgium	795735	⤷ Start Trial
Canada	1015360	⤷ Start Trial
Canada	1048027	⤷ Start Trial
Switzerland	556815	⤷ Start Trial
Germany	2310918	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: RE30577

Summary for Patent: RE30577