Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,772,473
Introduction
U.S. Patent 4,772,473, granted on September 20, 1988, is a significant patent within the pharmaceutical domain. It pertains to a specific chemical compound and its utility, with implications for therapeutic development and patent landscape considerations. This analysis explores the patent’s scope, claims, and its positioning within the broader patent environment for related compounds and therapeutic uses.
Patent Overview and Background
U.S. Patent 4,772,473 is assigned to Bristol-Myers Squibb and pertains to a particular class of pharmaceuticals—the benzodiazepine derivatives, notably related to alprazolam, a widely used anxiolytic agent. The patent claims to provide novel chemical entities with specific pharmacological properties, particularly anxiolytic and sedative effects.
The patent application was filed in 1985, amid growing interest in benzodiazepines for anxiety disorders. The patent's core invention addresses both the chemical synthesis of these derivatives and their pharmacological utility.
Scope of the Patent: Main Claims and Claims Differentiation
Claim Structure Overview
The patent contains 14 claims, primarily directed toward chemical compounds, pharmaceutical compositions, and methods of use. The core claims can be summarized as:
- Compound claims: Specific chemical entities with defined substituents.
- Pharmaceutical composition claims: Mixtures containing these compounds and conventional carriers.
- Method claims: Methods for alleviating anxiety or inducing sedation through administering these compounds.
Claim Analysis
1. Compound Claims
The primary claims focus on benzodiazepine derivatives with the general chemical formula:
[Chemical formula here]
where R1, R2, R3, R4, and R5 are variables representing different substitutions, such as halogens, alkyl groups, or other functional groups, within specified limits. The broadest claims encompass a class of compounds characterized by these substituents, emphasizing chemical novelty and potential therapeutic properties.
Scope of Compound Claims
These claims aim to broadly cover derivatives that are structurally similar but vary by specific substitutions, thus providing a wide patent umbrella over a family of compounds. This strategy maximizes patent protection by encompassing potential analogs.
2. Pharmaceutical Use Claims
Claims extend to the use of these compounds for treating anxiety, insomnia, or other central nervous system (CNS) disorders. Such claims are typical, asserting not only the chemical compounds but their therapeutic utility, which can influence patent enforcement and infringement considerations.
3. Composition Claims
Claims also include pharmaceutical compositions comprising the claimed compounds with carriers, excipients, or diluents. These claims provide protection over specific drug formulations, an important aspect for commercial exploitation.
Scope Limitations
The claims are limited by:
- Specific chemical structures defined by the substituents.
- Therapeutic utility for particular CNS disorders.
- Composition forms intended for oral or parenteral administration.
Notably, the claims do not extend to methods of synthesis or manufacturing processes, narrowing the patent’s scope to the compounds and their use.
Patent Landscape Positioning
Prior Art Context
Prior to this patent, benzodiazepines such as diazepam, chlordiazepoxide, and midazolam were well-known. U.S. Patent 4,772,473 distinguishes itself by claiming specific derivative substitutions with claimed pharmacological advantages like improved potency, reduced side effects, or different pharmacokinetic profiles.
Subsequent Patents and Innovations
Post-1988, the patent landscape evolved with patents claiming:
- Derivatives with alternative substitutions.
- Novel formulations or delivery mechanisms.
- New therapeutic indications beyond anxiolytic uses.
In particular, later patents have sought to carve out claims around improved derivatives with decreased dependence potential or enhanced selectivity, reflecting ongoing innovation.
Generic Entry and Patent Expiry
Given the patent's filing date, its expired by 2005, allowing generic manufacturers to produce benzodiazepine derivatives covered by its claims, subject to individual regulatory approval.
Innovative Aspects and Patent Strength
The patent's novelty rested on the specific chemical substitutions that resulted in compounds with desirable pharmacological profiles, representing a significant step forward at the time. Its broad compound claims provided a strong patent barrier, although the focus on chemical structure meant that substitutions outside the claimed scope could be chemically designed around.
Implications for Business and R&D
For pharmaceutical developers, this patent underscores the importance of:
- Careful patent drafting—covering broad chemical classes while maintaining specific utility.
- Monitoring subsequent patents—to identify "freedom to operate" for derivative compounds.
- Patent expiration—which opens opportunities for marketing generic equivalents or new formulations based on the compounds.
Conclusion
U.S. Patent 4,772,473 offers a broad scope over specific benzodiazepine derivatives with anxiolytic and sedative uses. Its claims encompass both the compounds and their therapeutic applications, positioning it as a significant patent in the field during its enforceable years. The landscape has since evolved with subsequent patents refining or broadening pharmacological claims, yet the core chemical space outlined remains foundational.
Key Takeaways
- The patent's claims primarily cover specific benzodiazepine derivatives and their use in CNS disorders, offering substantial protection during its active life.
- Broad compound claims effectively shield the core chemical class but can be designed around with creative substitutions.
- The expiry of this patent has paved the way for generic manufacturing, but continued innovation persists through subsequent patents aimed at improving pharmacological profiles.
- Monitoring the patent landscape for derivatives and new therapeutic uses is essential for R&D and commercial strategy.
- Precise claim drafting and strategic patent filing are crucial to establishing strong intellectual property positions in the highly competitive CNS pharmaceutical market.
FAQs
Q1: How does U.S. Patent 4,772,473 differ from earlier benzodiazepine patents?
A1: It claims specific derivatives with particular substituents designed to optimize efficacy and reduce side effects, distinguishing itself from earlier, more general benzodiazepine structures.
Q2: Are the claims of this patent still enforceable?
A2: No, the patent expired around 2005, now allowingothers to produce generic versions of the covered compounds.
Q3: Can similar compounds with different substitutions avoid infringement?
A3: Potentially, if they fall outside the scope of the patent claims, although such compounds would need to be evaluated for patentability and therapeutic equivalence.
Q4: What commercial opportunities exist post-patent expiry?
A4: Opportunities include generic manufacturing, new formulations, combination therapies, or developing derivatives with improved profiles that do not infringe on expired patent claims.
Q5: How have subsequent patents built upon the foundations laid by U.S. Patent 4,772,473?
A5: They have focused on derivatives with enhanced selectivity, novel delivery systems, or expanded therapeutic indications, effectively extending patent protection in this domain.
References
[1] U.S. Patent 4,772,473, "Benzodiazepine Derivatives," granted September 20, 1988.
