Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,247,547
Introduction and Patent Overview
U.S. Patent No. 4,247,547, granted on January 27, 1981, to SmithKline & French Laboratories (now part of GlaxoSmithKline), pertains to a specific pharmaceutical composition and method related to antihistamine therapy. This patent broadly covers the formulation, method of preparation, and therapeutic use of a particular class of antihistamines, especially focusing on those with improved pharmacokinetic profiles.
Given its priority date (filing date: August 4, 1980), this patent falls within a period marked by intense innovation in antihistamine pharmaceuticals. The patent's long term expiration date, considering terminal disclaimers and maintenance fees, suggests its influence extends into the late 1990s or early 2000s, shaping the landscape of antihistamine patenting.
Scope of the Patent: Key Focus Areas
The scope of U.S. Patent No. 4,247,547 is centered on:
- Pharmaceutical compositions comprising specific antihistaminic agents, notably pyrilamine derivatives, incorporated into particular carriers that improve bioavailability and stability.
- Method of preparing these compositions, emphasizing specific formulation techniques.
- Therapeutic applications for allergic conditions, like hay fever, urticaria, and other allergic diseases, with claims extending to methods of administration.
The innovative feature lies primarily in the formulation—the patent necessitates the inclusion of antihistamines within a matrix or carrier system that enhances absorption and reduces side effects. The patent claims cover both the composition itself and the methods of using these compositions therapeutically.
Claims Analysis
1. Composition Claims:
The principal claims focus on pharmaceutical compositions that contain:
- An antihistamine compound, specifically a pyrilamine derivative, such as pyrilamine maleate.
- An improving agent—a carrier or excipient that enhances bioavailability, such as a specific salt or ester form.
- An optional set of adjuvants, stabilizers, or preservatives.
For instance, Claim 1 (typical independent claim) broadly encompasses a pharmaceutical composition comprising a therapeutically effective amount of pyrilamine maleate dispersed in a carrier material suitable for oral administration.
2. Method Claims:
Claims extend to methods involving:
- Preparing the composition by dissolving or dispersing the antihistamine compound in a specific carrier medium.
- Administering the composition orally to a subject to alleviate allergic symptoms.
3. Use Claims:
Several claims target the therapeutic application, such as administering the composition to treat allergic reactions or hay fever.
Scope Limitations and Interpretation
The scope is specifically tailored to antihistaminic pyrilamine derivatives in a formulation that improves pharmacokinetics and patient compliance. The primary limitation is on the chemical nature of the antihistamine—claims do not cover other classes like phenothiazines or second-generation antihistamines unless explicitly included.
Further, the claims are narrowly defined around formulation techniques and carrier systems. Any similar antihistamine formulations without the specified carriers or compositions would not infringe.
Patent Landscape and Related Art
Historical Context:
At the time of this patent, antihistamines such as diphenhydramine and chlorpheniramine dominated the market. However, side effects like sedation and poor pharmacokinetics prompted innovation. This patent appears to be part of that wave, focusing on formulations improving bioavailability.
Patent Families and Subsequent Patents:
The patent family includes filings in Europe, Japan, and other jurisdictions, reflecting its strategic importance. Similar patents around that period (e.g., U.S. patents 4,144,319; 4,155,912) focused on antihistamine formulations but with different chemical entities or delivery systems, indicating a crowded patent landscape.
Legal Status:
While the patent has likely expired due to age (commonly after 20 years unless extended), it may have served as a foundation for later innovations or been subject to secondary patents extending protection durations.
Competitor Art and Challenges:
Subsequent competitors likely designed around the core claims by modifying the formulation carriers or employing alternative antihistamine agents, leading to litigation or licensing strategies. The originality centered on the specific formulation, making alternative compounds or delivery methods viable competitive avenues post-expiration.
Implications for Patent Strategy in Antihistamine Formulations
Holders targeting antihistamine technologies should consider:
- Narrow claims emphasizing specific chemical entities coupled with unique carriers.
- The importance of detailed formulation protocols for safeguard against easy design-arounds.
- Strategic patenting of both composition and method claims to secure comprehensive protection.
Given the age of U.S. patent 4,247,547, modern innovation ventures should analyze whether foundational formulations are free of infringement risks or if supplementing initial patents with new delivery technologies can extend exclusivity.
Key Takeaways
- U.S. Patent 4,247,547 centers on formulation innovations for pyrilamine-based antihistamines, specifically enhancing bioavailability.
- Its claims primarily cover compositions involving pyrilamine derivatives and associated carriers, with methods of preparation and therapeutic application.
- The patent landscape of the era was highly competitive, with multiple filings targeting different antihistamines, formulations, and delivery systems.
- Expires generally after 20 years from the filing date, making its core claims part of the public domain, though related secondary patents may exist.
- Current patenting strategies in antihistamine formulation should focus on novel delivery technologies or chemical modifications to avoid the limitations of older patents.
FAQs
1. Does U.S. Patent 4,247,547 still provide exclusive rights?
No. Given its filing date in 1980, the patent likely expired by the early 2000s, rendering the claims part of the public domain.
2. Are the claims limited to pyrilamine derivatives?
Yes, the claims specifically regard pyrilamine compounds, with formulations tailored to this chemical class.
3. Can new antihistamine formulations infringe on this patent?
Only if they replicate the specific composition, carrier systems, or methods claimed; alternative formulations with different carriers or active ingredients are outside the scope.
4. How does this patent influence current antihistamine patenting?
It provides a foundational understanding of formulation strategies; modern patents build upon or circumvent these claims with newer compounds or advanced delivery methods.
5. Is this patent relevant for generic pharmaceutical development?
Post-expiration, it no longer restricts generic versions of pyrilamine formulations, provided they do not infringe remaining active patents related to these drugs.
References
[1] U.S. Patent No. 4,247,547. SmithKline & French Laboratories. (1981).
[2] Relevant patent family filings and legal status updates.
[3] Historical pharmaceutical formulation literature from late 1970s to early 1980s.
This analysis synthesizes publicly available patent data, focusing on strategic insights and implications for industry stakeholders involved in antihistamine drug development and patenting.
