Details for Patent: 6,780,877

Summary for Patent: 6,780,877

Title:	Acid addition salt of optically active piperidine compound and process for preparing the same
Abstract:	The present invention is to provide a benzenesulfonic acid salt and a benzoic acid salt of (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid represented by the formula (I):wherein * represents an asymmetric carbon, which are excellent in antihistaminic activity and anti-allergic activity, and a process for producing the same.
Inventor(s):	Jun-ichiro Kita, Hiroshi Fujiwara, Shinji Takamura
Assignee:	Ube Corp , Tanabe Pharma Corp
Application Number:	US09/949,809
Patent Claim Types: see list of patent claims	Composition; Compound; Process;

United States Patent 6,780,877 Scope, Claims, and Landscape for (S)-Optically Active Piperidine Benzenesulfonate Salts

United States Patent 6,780,877 is a salt-focused composition and process patent. Its claim set centers on (i) a specific benzenesulfonic acid salt form of an (S)-configured optically active piperidine compound defined by formula (I), (ii) a salt-formation process that converts the corresponding (S)-piperidine compound to the benzenesulfonate using benzenesulfonic acid, and (iii) a pharmaceutical composition containing that specific benzenesulfonate salt as the active ingredient. The practical IP risk profile is therefore highest for products marketed in the United States that use the benzenesulfonate salt form of the identified (S)-piperidine API.

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What does U.S. Patent 6,780,877 claim: benzenesulfonate salt of an (S)-optically active piperidine compound?

Claim 1: salt product-by-structure scope

Claim 1 is directed to: “A benzenesulfonic acid salt of an optically active piperidine compound represented by the formula (I)… wherein * represents an asymmetric carbon, which has an absolute configuration of (S).”

Scope drivers

• Salt identity: the specific counterion is benzenesulfonic acid (benzenesulfonate).
• Stereochemistry: the molecule has an asymmetric carbon with absolute configuration (S).
• Structural tethering: the optically active piperidine compound is limited to the compound “represented by formula (I)” as defined in the patent specification.
• Excludes:
  • other sulfonate salts (e.g., toluenesulfonate, methanesulfonate) unless they also qualify as “benzenesulfonic acid salt.”
  • other stereoisomers or racemates unless the absolute configuration matches (S) as required by claim language.

Functional reach

• Claim 1 is a classic “API salt” claim. It is not confined to a dosage form, but it does not cover non-salt free base forms or salt forms other than benzenesulfonate.

What the asymmetric carbon language means in claim practice

The patent ties protection to the presence of an asymmetric carbon with absolute configuration (S). In litigation and infringement analysis, this typically becomes a question of:

• whether the marketed material contains the (S)-enantiomer (not a mixture),
• whether the marketed compound’s stereochemical identity matches the formula (I) as interpreted by the patent’s definition in the specification and drawings.

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How broad is the patent to cover other salt forms, stereoisomers, and crystal forms?

Salt-form substitutions

Claim 1 requires a benzenesulfonic acid salt. If a competitor switches to:

• a different sulfonate counterion, or
• a non-sulfonate counterion (e.g., HCl, maleate, fumarate), it typically avoids claim 1. Claim 3 also follows the same salt constraint for the composition.

Stereochemical substitutions

Because the claim is explicit about absolute configuration (S), a competitor selling a different enantiomer or mixture does not fall within the literal wording of claim 1. If a product contains a mixture that includes the (S)-enantiomer, infringement can become dependent on whether the “absolute configuration” requirement can be read as satisfied by admixture or whether it demands a single absolute configuration. Patent practice usually treats enantiomer-specific claims as requiring the specified stereochemical state in the product.

Polymorphs and crystal engineering

The provided claim set does not add explicit limitations to polymorphic form, hydrate/solvate state, particle size, or specific solid-state characteristics. If the benzenesulfonate salt is used, claim 1 can reach multiple physical forms, assuming the stereochemistry and salt identity are present.

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What is the process claim 2 actually covering: converting the (S)-piperidine to a benzenesulfonate?

Claim 2: salt-forming process

Claim 2 recites a process for preparing the optically active piperidine compound according to claim 1, where the (S)-configured piperidine (formula (I)) is subjected to a salt-forming reaction with benzenesulfonic acid.

Scope drivers

• Input requirement: an optically active piperidine compound of formula (I) with absolute configuration (S).
• Operation: “salt forming reaction with benzenesulfonic acid.”
• Output: the salt corresponding to claim 1.

Why this matters Process claims create a second enforcement vector:

• not only for finished dosage forms (composition claim 3),
• but also for manufacturing steps that create the benzenesulfonate salt.

A manufacturer who buys the benzenesulfonate salt from a third party can still face process exposure if they perform a salt-forming reaction with benzenesulfonic acid in the United States (or where the process is used). Conversely, if a competitor sources a benzenesulfonate from a supplier and does not perform the salt-forming reaction, direct infringement of a salt-formation process may be harder to establish, depending on the patent claim elements, induced/contributory theories, and the location of activity.

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What does claim 3 cover: pharmaceutical composition using this exact benzenesulfonate salt?

Claim 3: composition claim tied to the specific API

Claim 3 covers a pharmaceutical composition comprising “a benzenesulfonic acid salt of (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid” as the effective ingredient.

Scope drivers

• Active ingredient specificity: the claim names the API and requires the benzenesulfonic acid salt of that (S)-butanoic acid piperidine structure.
• Dosage form and formulation breadth: the claim, as provided, does not limit to a particular dosage form (tablet, capsule, liquid), excipient class, or release profile. It is a standard “composition includes X active ingredient” structure.
• Excludes:
  • the free acid / free base without the benzenesulfonate counterion,
  • other counterion salts,
  • other stereoisomers.

Enforcement posture For drug products, claim 3 is the most direct. If a generic or branded competitor markets a formulation whose active ingredient is the claimed benzenesulfonate salt, claim 3 can be asserted without proving how it was made.

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What is the compound identity embedded in the claims, and how does it anchor infringement?

Claim 3 provides the clearest chemical anchor:
(S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid in the form of its benzenesulfonic acid salt.

That identity means:

• infringement analysis can focus on whether the marketed API is the benzenesulfonate of this (S)-configured structure, rather than arguing broad “formula (I)” interpretation alone.
• the formula (I) scope in claim 1 should align with the named compound in claim 3, reducing ambiguity on what the formula (I) covers.

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How strong is the patent estate for this API salt: product, composition, and manufacturing coverage?

Claim coverage map

Claim	Category	Key limitations	Best use in enforcement
1	Product (salt)	benzenesulfonic acid salt + formula (I) + absolute configuration (S)	Target API salt use and any product where the salt is the active ingredient
2	Process	salt formation using benzenesulfonic acid on (S)-piperidine	Target manufacturing steps that create the benzenesulfonate
3	Composition	benzenesulfonic acid salt of named (S)-API in a pharmaceutical composition	Target finished dosage forms and “generic drug” products with same active ingredient

Strength characteristics

• Tight counterion limitation: benzenesulfonate is a narrow salt definition, which can be strong if competitors cannot design around by changing counterions.
• Stereochemical limitation: requires (S), another narrowing element.
• No extra solid-state qualifiers in the provided claims: can improve practical coverage across polymorphs and particle sizes so long as the salt and stereochemistry match.

Weakness characteristics

• Design-around path exists via other salts: if a competitor can switch to a different counterion while still meeting bioequivalence or regulatory criteria, they can avoid literal infringement of claim 1 and claim 3. That design-around can materially reduce the monetization upside unless other patents cover alternate salt forms or the free base / core structure.

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What generic entry risks exist if a challenger files an ANDA or 505(j) with a different salt?

Literal infringement risk for ANDA challengers

• If the challenger uses the same benzenesulfonate salt: higher risk for claim 3 (composition) and claim 1 (API salt), plus process risk for claim 2 if manufacturing performs benzenesulfonate salt formation with benzenesulfonic acid.
• If the challenger uses a different salt: avoids claim 1 and claim 3, reducing direct risk. A counterclaim may still attempt doctrine-of-equivalents style arguments, but the explicit “benzenesulfonic acid salt” limitation makes that a steeper climb.

Strategy for challengers

In practice, a challenger will often choose one of:

1. license the benzenesulfonate or use it under authorization; or
2. switch to an alternate salt form, assuming no other patents block that design; or
3. contest validity/enforceability for the salt claims (e.g., obviousness arguments around salt formation for known APIs).

The patent’s narrow counterion requirement is the key variable in this decision tree.

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What does Paragraph IV risk look like for this specific patent?

For Paragraph IV assertions against a listed US patent tied to a branded drug’s active ingredient salt:

• the risk is highest if the challenger’s ANDA product uses the benzenesulfonate;
• the risk is lower if the challenger’s formulation uses a different salt but still achieves comparable exposure.

In litigation, claim construction will focus on:

• the definition of formula (I),
• stereochemical scope of the (S) designation,
• and what exactly counts as a “benzenesulfonic acid salt” of the specified (S)-compound (including salt purity and whether the material contains the required counterion).

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How does this patent estate compare with typical salt-only portfolios?

Typical salt-only estate vs this patent

Salt-only patents commonly:

• claim the salt form,
• claim salts in compositions,
• sometimes claim a preparation method.

U.S. 6,780,877 matches that pattern with one important enforcement advantage: it includes both product/composition and a salt-formation process claim. Many competitors can design around a product salt claim by switching counterions but still cannot easily avoid process or composition claims if they must use the same salt for solubility/formulation performance and the broader patent family blocks alternate salts.

What would be needed to fully block design-around

To fully neutralize counterion switching, the broader patent family usually includes one or more of:

• a claim on the free base / acid form independent of salt,
• a claim on alternate salts,
• a method-of-use or formulation performance patent tied to a dosage form that still requires the same API identity,
• or a claim on manufacturing steps beyond simple salt formation.

Those additional layers are not visible in the claim text provided here, so the monetization of 6,780,877 alone is most defensible against competitors who stay with the benzenesulfonate salt.

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What is the likely relationship between claim 1 formula (I) and claim 3’s named API?

Claim 3’s named compound strongly suggests that formula (I) in claim 1 is the same chemical entity as:
(S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid.

That relationship matters because:

• claim 1 should not be read as covering a broader class of piperidine derivatives beyond the named API,
• it should instead track a single API scaffold with a controlled stereochemical parameter.

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Patent landscape checklist for U.S. 6,780,877 (what to map, claim-by-claim)

Because the claims provided narrow the scope to one salt form and one stereoisomer, a landscape exercise should prioritize these dimensions:

1) Family members in the U.S.

• Patent numbers in the same priority family with:
  • free base / free acid claims,
  • alternate salt claims,
  • stereoisomer-specific claims (other than (S)),
  • crystalline form claims (if any),
  • or broader synthetic route claims that are not limited to salt formation with benzenesulfonic acid.

2) Orange Book listing linkage

• Determine which approved NDA/ANDA products list 6,780,877 in the Orange Book.
• Map whether the listed active ingredient is explicitly the benzenesulfonate salt or another form.

3) Litigation and settlements

• Identify whether the patent has been asserted in:
  • district court actions (infringement),
  • ANDA Paragraph IV litigations (automatic stays),
  • or ITC actions.
• Determine whether any settlement includes:
  • a launch date,
  • a design-around covenant (alternate salt),
  • or a license to use the benzenesulfonate.

4) Design-around feasibility

• For competitors, evaluate:
  • whether alternate counterions maintain the same PK/solubility profile,
  • whether formulation differences trigger other patent protections,
  • whether the chosen alternate salt avoids not only 6,780,877 but the rest of the estate.

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When does U.S. 6,780,877 lose exclusivity? What does patent term and extensions depend on?

No dates are provided in the input. Without the patent’s filing date, priority date, issuance date, and any terminal disclaimer or PTA data, exclusivity timing cannot be computed accurately from the claim text alone. The claim scope analysis above is complete, but the exclusivity timeline is not determinable from the information given.

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Key Takeaways

• U.S. 6,780,877 is primarily a benzenesulfonate salt patent with stereochemical and structural constraints: it covers the benzenesulfonic acid salt of an (S)-configured piperidine compound defined by formula (I).
• Claim 1 is the core product-by-structure salt claim.
• Claim 2 adds a salt-formation process limited to using benzenesulfonic acid to form the benzenesulfonate salt from the (S)-piperidine compound.
• Claim 3 is a pharmaceutical composition claim that names the active ingredient as the benzenesulfonate salt of (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid.
• The main design-around lever is switching to a different counterion salt, which can avoid the “benzenesulfonic acid salt” limitation if no other patents cover alternate salt forms or the underlying (S)-API regardless of salt.

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FAQs

1) Does U.S. 6,780,877 cover the free base or free acid of the piperidine compound?

No. The provided claims require a benzenesulfonic acid salt.

2) Can an ANDA avoid this patent by using a different salt like HCl or maleate?

If the challenger’s active ingredient is not the benzenesulfonate, it can avoid the literal scope of claims 1 and 3, subject to other patents in the estate.

3) Does claim 2 cover crystallization steps after the salt is formed?

The provided claim language focuses on the salt-forming reaction with benzenesulfonic acid. Post-formation crystallization is not explicitly recited in the claim text provided.

4) What stereochemistry is required for infringement?

The claims require absolute configuration (S) for the asymmetric carbon in the optically active piperidine compound.

5) Does claim 3 restrict the dosage form?

As provided, claim 3 is not limited to a specific dosage form; it broadly covers a pharmaceutical composition containing the specified benzenesulfonate salt.

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References

1. United States Patent 6,780,877 (claims provided in prompt).

Drugs Protected by US Patent 6,780,877

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 6,780,877

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	8-347851	Dec 26, 1996
Japan	8-347853	Dec 26, 1996
Japan	8-347895	Dec 26, 1996

International Family Members for US Patent 6,780,877

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	217872
Australia	7890698
Canada	2275987
China	1098262
China	1231478
China	1242013
China	1446812