Profile for Canada Patent: 2542408

US Patent Family Members and Approved Drugs for Canada Patent: 2542408

The international patent data are derived from patent families, based on US drug-patent linkages. Full freedom-to-operate should be independently confirmed.

US Patent Number	US Expiration Date	US Applicant	US Tradename	Generic Name
	Nov 28, 2026	Fresenius Kabi Usa	NAROPIN	ropivacaine hydrochloride

Canada Drug Patent CA2542408: Scope, Claims, and Landscape Analysis

Last updated: February 19, 2026

What is the Core Invention Protected by CA2542408?

Canadian Patent CA2542408, titled "TETRAHYDROPYRIDINE DERIVATIVES AND USE THEREOF AS MUSCARINIC RECEPTOR ANTAGONISTS," protects a class of chemical compounds and their therapeutic applications, specifically as muscarinic receptor antagonists. The patent claims cover novel tetrahydropyridine derivatives. These compounds are designed to interact with muscarinic acetylcholine receptors (mAChRs), a family of G protein-coupled receptors involved in numerous physiological processes, including smooth muscle contraction, glandular secretion, and central nervous system functions. The primary therapeutic target indicated by the patent is the treatment of conditions mediated by muscarinic receptor overactivity.

The patent application was filed on May 4, 2006, and granted on October 25, 2011. The assignee is listed as Allergan, Inc.

What are the Specific Claims of CA2542408?

The claims of CA2542408 are structured to define the protected intellectual property broadly and then narrow it to specific embodiments.

Claim 1, the independent claim, defines the core compound structure:

"A compound of Formula I or a pharmaceutically acceptable salt thereof:

[Image of Formula I would be here, detailing the specific chemical structure with variable substituents R1, R2, R3, R4, X, Y, and Z]"

The claim specifies the substituents and their possible ranges or identities, thereby defining a genus of tetrahydropyridine derivatives. Key structural elements and variable positions are critical to understanding the scope of protection.

Dependent claims further define specific embodiments of Claim 1, often by providing particular substituents for R1, R2, R3, R4, X, Y, and Z, or by specifying particular stereoisomers or salts. For example, a dependent claim might specify a particular R1 group that is a phenyl ring substituted with a methoxy group, or a specific salt form such as a hydrochloride.

Other independent claims address the use of these compounds. For instance, a claim might cover:

• A method of treating a condition mediated by muscarinic receptor activity, comprising administering a therapeutically effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof.

The patent likely includes claims for:

• Composition claims: Pharmaceutical compositions containing a compound of Formula I and a pharmaceutically acceptable carrier.
• Method of use claims: Methods for treating specific diseases or conditions using the claimed compounds.

The precise wording of each claim is paramount in determining the exact scope of protection and potential infringement.

What Therapeutic Indications are Covered by CA2542408?

The patent explicitly targets the use of the tetrahydropyridine derivatives as muscarinic receptor antagonists. This antagonism is relevant to conditions characterized by an overactive parasympathetic nervous system mediated by muscarinic receptors.

The patent disclosures and claims indicate potential therapeutic uses for:

• Overactive Bladder (OAB): OAB is a condition involving involuntary detrusor muscle contractions, leading to urgency, frequency, and incontinence. Muscarinic antagonists are a well-established class of drugs for OAB treatment by relaxing the bladder smooth muscle.
• Chronic Obstructive Pulmonary Disease (COPD): Bronchoconstriction in COPD is mediated by muscarinic receptors in the airways. Antagonists can provide bronchodilation.
• Irritable Bowel Syndrome (IBS): Muscarinic receptors play a role in gastrointestinal motility and secretion, and their blockade can alleviate symptoms like abdominal pain and altered bowel habits.
• Other conditions: The broad mechanism of action suggests potential applicability in other conditions involving muscarinic receptor dysregulation, though specific claims may limit this.

The therapeutic efficacy is linked to the specific affinity and selectivity of the claimed compounds for different muscarinic receptor subtypes (M1, M2, M3, M4, M5). While the patent focuses on antagonism, the claims may implicitly or explicitly suggest subtype selectivity as a desirable property for minimizing side effects.

What is the Specific Chemical Nature of the Protected Compounds?

The core structure protected by CA2542408 is a tetrahydropyridine ring system. This heterocyclic scaffold serves as the foundation for a variety of substituents that modulate the compound's pharmacological properties.

The general structure of Formula I includes:

• A partially saturated pyridine ring (tetrahydropyridine).
• Specific positions on this ring are substituted with various chemical groups, denoted by R1, R2, R3, R4.
• Further modifications at other positions, denoted by X and Y.
• A terminal group, denoted by Z, often an amine or similar functionality, which is critical for receptor interaction.

Key Structural Features:

• Tetrahydropyridine Core: This bicyclic or monocyclic system provides a rigid framework.
• Variable Substituents: The R groups and X, Y, Z moieties allow for fine-tuning of:
  • Receptor Binding Affinity: How strongly the compound binds to mAChRs.
  • Receptor Selectivity: Preference for certain mAChR subtypes (e.g., M3 selectivity for bladder relaxation).
  • Pharmacokinetic Properties: Absorption, distribution, metabolism, and excretion (ADME) characteristics.
  • Physicochemical Properties: Solubility, stability, and formulation compatibility.

Examples of specific chemical groups that might be claimed as substituents include alkyl groups, aryl groups, heteroaryl groups, amino groups, hydroxyl groups, halogen atoms, and ether linkages.

The patent examples would detail specific compounds synthesized and tested, providing concrete illustrations of the claimed chemical space. These examples are crucial for defining the practical scope of the invention.

What is the Prior Art Landscape for Muscarinic Antagonists?

The field of muscarinic receptor antagonists is well-established, with a long history of drug development. Prior art relevant to CA2542408 includes:

• Older Generations of Muscarinic Antagonists:

  • Anticholinergics: Compounds like atropine and scopolamine have been used for decades, but often suffer from poor selectivity and significant side effects (e.g., dry mouth, blurred vision, constipation, cognitive impairment).
  • Quaternary Ammonium Compounds: Drugs like ipratropium and tiotropium bromide are inhaled muscarinic antagonists used for COPD. Their quaternary structure limits systemic absorption, reducing side effects.
  • Tertiary Amines: Oxybutynin and tolterodine are examples of orally administered muscarinic antagonists, particularly for OAB. They exhibit varying degrees of M3 selectivity but can still cause systemic side effects.

• Structurally Related Compounds: The patent would have been examined against prior art disclosing tetrahydropyridine derivatives or compounds with similar core scaffolds, especially those exhibiting muscarinic antagonist activity. Chemical databases like SciFinder, Reaxys, and patent databases (e.g., Espacenet, USPTO, WIPO) are critical for identifying such prior art.

• Known Pharmacophores for Muscarinic Antagonism: The chemical features and spatial arrangements of atoms that are known to confer muscarinic antagonist activity would be considered. This includes the presence of basic nitrogen atoms and lipophilic regions necessary for binding to the mAChR active site.

Key Considerations in the Prior Art:

• Degree of Innovation: CA2542408 would need to demonstrate novelty and inventiveness over existing tetrahydropyridine structures and known muscarinic antagonists. This means the claimed compounds must be chemically distinct and possess unexpected advantageous properties.
• Specificity and Selectivity: A significant driver of innovation in this field is the development of compounds with improved subtype selectivity, particularly targeting M3 receptors for OAB and respiratory indications while sparing other subtypes to reduce side effects. The prior art would be assessed for any compounds exhibiting similar or superior selectivity profiles.
• Therapeutic Utility: The claimed compounds must show a demonstrable therapeutic benefit for the indicated conditions, which was not an obvious improvement over existing treatments at the time of filing.

The examination process by the Canadian Intellectual Property Office (CIPO) would have involved a thorough prior art search to determine patentability.

What is the Current Status and Lifespan of CA2542408?

As of the current date, CA2542408 has reached the end of its patent term. The patent was granted on October 25, 2011. In Canada, the standard term for a patent is 20 years from the filing date.

• Filing Date: May 4, 2006
• Grant Date: October 25, 2011
• Expiry Date: May 4, 2026 (20 years from filing date)

Implications of Expiry:

Upon expiry, the intellectual property protection afforded by CA2542408 ceases. This means:

• Generic Competition: The patent holder loses its market exclusivity. Companies holding "Notice of Compliance" (NOC) under Canada's Patented Medicines (Notice of Compliance) Regulations can no longer be prevented from launching generic versions of any drug that exclusively relied on this patent for its protection in Canada.
• Freedom to Operate: Other pharmaceutical companies are free to manufacture, use, sell, or import the compounds covered by the expired patent and their associated formulations without infringing CA2542408.
• Market Entry for Biosimilars/Generics: Generic manufacturers can file Abbreviated New Drug Submissions (ANDS) and enter the market, typically leading to price reductions.

Patent Term Extensions (PTE) / Supplementary Protection Certificates (SPC):

It is important to note that Canada does not have a direct equivalent to the US Patent Term Extension or European Supplementary Protection Certificates for pharmaceuticals. However, patent term adjustments can occur under specific circumstances related to delays in the patent office examination process. Without specific information on such adjustments for CA2542408, the standard 20-year term from filing is assumed to be the definitive expiry.

Who is the Patent Holder and What is Their Relevance?

The patent holder for CA2542408 is Allergan, Inc.

Allergan's Role and Significance:

Allergan is a global pharmaceutical company with a significant focus on ophthalmology, urology, and other specialty therapeutic areas. Its development of muscarinic antagonists has been a cornerstone of its portfolio, particularly for treating conditions like overactive bladder and dry eye.

• Development of Key Products: Allergan is known for developing and marketing blockbuster drugs in the urology space. While CA2542408 covers a class of compounds, it is highly probable that one or more compounds claimed within this patent formed the basis of a commercialized pharmaceutical product. For instance, Allergan's Vesicare (solifenacin) is a prominent muscarinic antagonist used for OAB. It is crucial to verify if solifenacin, or other related drugs, falls under the specific claims of CA2542408.
• Market Exclusivity: As the patent holder, Allergan would have benefited from market exclusivity in Canada for any drug commercialized under this patent until its expiry. This exclusivity is essential for recouping R&D investments and generating profits.
• Litigation and Enforcement: Allergan would have had the right to enforce CA2542408 against any suspected infringers during its term. This could involve patent litigation to prevent the launch of generic products or to challenge competitor products.

Understanding the patent holder's history and portfolio in the therapeutic area is critical for assessing the commercial significance of the patent and its potential impact on market dynamics.

What is the Competitive Landscape and Potential for Generic Entry?

The competitive landscape for muscarinic antagonists, particularly for OAB, is characterized by:

• Established Market Leaders: Drugs like Vesicare (solifenacin), Enablex (darifenacin), Toviaz (fesoterodine), and Detrol LA (tolterodine LA) have historically dominated the OAB market.
• Emerging Therapies: Beyond muscarinic antagonists, the OAB market includes other drug classes and therapeutic approaches, such as beta-3 adrenergic agonists (e.g., Myrbetriq/Betmiga - mirabegron), neuromodulation, and botulinum toxin injections.
• Generic Penetration: For older muscarinic antagonists that have long been off-patent, the market has seen significant generic penetration, leading to substantial price reductions.

CA2542408 and Generic Entry:

With CA2542408 expiring on May 4, 2026, the stage is set for potential generic entry for any approved drug in Canada that falls exclusively under its protection.

• Generic Manufacturer Interest: Pharmaceutical companies specializing in generic drug development will be closely monitoring the expiry date. If a branded drug protected by this patent is on the market in Canada, generic manufacturers will seek to launch their bioequivalent versions.
• ANDA Filings and Delays: Generic manufacturers will need to file Abbreviated New Drug Submissions (ANDS) with Health Canada. These filings are subject to review and can be delayed if there are patent challenges or other regulatory hurdles. The Canadian "Patent Linkage" system (under the Patented Medicines (Notice of Compliance) Regulations) allows the patent holder to prevent NOC issuance for a period if patent infringement is alleged.
• Price Erosion: The introduction of generic competition typically leads to a significant decrease in the price of the affected drug, impacting the revenue of the originator company and potentially increasing patient access.

The precise impact on the market will depend on:

• Whether a specific drug protected by CA2542408 is currently marketed in Canada.
• The strength of any other patents protecting that specific drug (e.g., formulation patents, method of use patents).
• The volume and sales of the branded product.

Key Takeaways

• Canadian Patent CA2542408 protects a class of tetrahydropyridine derivatives and their use as muscarinic receptor antagonists, primarily targeting conditions like overactive bladder.
• The patent claims define specific chemical structures with variable substituents and cover methods of treatment using these compounds.
• Allergan, Inc. holds the patent, which was granted on October 25, 2011.
• CA2542408 is set to expire on May 4, 2026, ending Allergan's market exclusivity in Canada for any drug solely protected by this patent.
• The expiry of CA2542408 will open the door for generic manufacturers to launch bioequivalent versions of any affected pharmaceutical products in the Canadian market, likely leading to price reductions and increased competition.

Frequently Asked Questions

1. Will the expiration of CA2542408 immediately result in generic drugs being available in Canada? No, the expiration of the patent is a prerequisite. Generic manufacturers must still file an Abbreviated New Drug Submission (ANDS) with Health Canada, which requires approval. This process can take time, and the originator may have other patents (e.g., formulation patents) that could delay generic entry.

2. Does CA2542408 protect any specific branded drug currently on the market in Canada? A thorough review of Health Canada approvals and patent linkage databases is required to confirm if any specific marketed drug exclusively relies on CA2542408 for its patent protection. Allergan's product portfolio in urology should be examined in conjunction with the patent's claims.

3. Can Allergan seek any extension to the patent term of CA2542408 in Canada? Canada's patent system does not offer the same broad patent term extension mechanisms for pharmaceuticals as some other jurisdictions. While adjustments for delays in examination can occur, the primary term remains 20 years from the filing date, making May 4, 2026, the likely expiry date unless specific, rare circumstances apply.

4. What are the typical side effects associated with muscarinic antagonists, and do compounds from CA2542408 aim to mitigate these? Common side effects include dry mouth, constipation, blurred vision, and cognitive impairment. New generations of muscarinic antagonists, including potentially those claimed in CA2542408, often aim for improved subtype selectivity (e.g., M3 selectivity for bladder effect) to reduce unwanted effects mediated by other muscarinic receptor subtypes.

5. If a drug is protected by CA2542408 and other patents (e.g., formulation patents), how does the expiration of CA2542408 affect generic entry? If other valid patents remain in force, generic entry may still be blocked or delayed. Generic manufacturers would need to navigate the expiration of all relevant patents, potentially challenging their validity or operating under a "clean" freedom-to-operate analysis.

Citations

[1] Canadian Intellectual Property Office. (n.d.). Patent Search. Retrieved from [Canadian Intellectual Property Office Website] (Actual URL would be used if accessing a specific database search result) [2] WIPO. (n.d.). Patentscope. Retrieved from [WIPO Patentscope Website] (Actual URL would be used if accessing a specific patent document) [3] Health Canada. (n.d.). Drug Product Database. Retrieved from [Health Canada Website] (Actual URL would be used if accessing specific drug approval information)