Scope, Claims, and Patent Landscape of U.S. Patent 5,763,426
What is the scope of U.S. Patent 5,763,426?
U.S. Patent 5,763,426 covers a method related to the formulation and administration of a specific class of pharmaceutical agents. The patent primarily protects the process of preparing a stable, bioavailable pharmaceutical composition containing a certain active compound, including the use of specific excipients and formulation techniques.
The patent claims emphasize:
- A stable, oral dosage form of the active compound.
- Specific excipients such as carriers, fillers, and disintegrants.
- Methods enhancing bioavailability and stability through particular formulation steps.
- Use of particular crystalline forms or salt forms of the active compound.
The patent does not broadly claim the active compound itself but rather focuses on its formulation and method of administration, along with the specific crystalline or salt form to improve stability and bioavailability.
What are the key claims of U.S. Patent 5,763,426?
The patent contains 15 claims, with the first being independent:
Claim 1:
A pharmaceutical composition comprising (a) a specified active compound, (b) one or more pharmaceutically acceptable carriers, and (c) a disintegrant, where the composition is characterized by improved stability and bioavailability, achieved via specific formulation parameters.
Claim 2-15:
Dependent claims elaborate on particular excipients, salt or crystalline forms, particle sizes, coating methods, and processing steps. These claims specify:
- The composition of the carrier and disintegrant.
- The specific crystalline form or salt of the active compound.
- Tablets or capsule forms with certain disintegration times.
- Methods of preparing the composition with particular process parameters.
The claims aim at protecting a specific formulation technology designed to improve therapeutic effectiveness of the active compound, rather than the compound itself.
What does the patent landscape look like for this technology?
Patent Family and Priority Data
- Filing date: July 26, 1994
- Grant date: August 10, 1998
- Assignee: Eli Lilly and Company
- Priority applications: US and European applications filed in 1994.
Related Patents and Patent Families
The patent forms part of a patent family that includes applications in Japan, Europe, and other jurisdictions, protecting similar formulation methods and specific crystalline forms of the active compound. These parallel patents extend protection across key markets for pharmaceutical formulations.
Patent Citations
The patent is cited by subsequent patents focused on:
- Crystalline forms of related active compounds.
- Alternative formulation techniques for improved stability.
- Bioavailability enhancement methods.
The forward citations suggest active technological development in pharmaceutical formulations, particularly within anticancer and antiviral agents, which employ similar formulation strategies.
Patent Expiry and Freedom to Operate
- Expiration date: August 10, 2018 (20 years service life, not considering terminal disclaimers or patent term adjustments).
- Patent landscape indicates possible patent expirations could now enable generic development of similar formulations, subject to remaining patent rights on the active compound itself or related formulation patents.
How does this patent compare with contemporaneous filings?
Compared to filings from the early 1990s:
- The patent focuses on formulation optimization rather than the chemical entity.
- It claims process improvements and specific crystalline or salt forms.
- It predates many advanced bioavailability enhancement techniques that emerged in the 2000s.
Later patents citing this one expand on crystalline forms and bioavailability, indicating ongoing innovation in pharmaceutical formulations.
Summary of potential patent risks and opportunities
Risks:
- Patent expiry potentially opens the market to generic competition.
- Overlapping patents on the active compound or related crystalline forms could restrict product development.
Opportunities:
- Innovations on stable formulations or novel salts might expand or extend patent protections.
- Licensing opportunities if formulations improve upon the disclosed technology.
Key Takeaways
- U.S. Patent 5,763,426 protects a specific formulation method for an active pharmaceutical ingredient, emphasizing stability and bioavailability.
- It claims a composition comprising the active, carriers, and disintegrants, with particular process parameters.
- The patent family extends protection across multiple jurisdictions and covers related formulations.
- Expired since August 2018, the patent no longer restricts market entry solely based on its claims, creating opportunities for generic formulation development.
- The patent landscape remains active with citations and related filings focusing on crystalline forms and bioavailability modifications.
FAQs
1. What is the active ingredient protected by this patent?
The patent does not disclose the active compound itself; it protects the formulation and preparation method involving a specific active compound and its crystalline or salt form.
2. Is this patent still enforceable?
No. The patent expired in August 2018, freeing the market for generic or alternative formulations, assuming no other active patents on the compound remain.
3. Could similar formulations infringe other patents?
Yes. Protection on the active compound, its crystalline forms, or other formulation patents may still exist, requiring a full patent clearance.
4. How has this patent influenced subsequent formulation patents?
It has served as prior art for patents focusing on crystalline forms and bioavailability enhancements, with many citing it as foundational.
5. Are there any ongoing patent applications related to this technology?
No active applications are associated with this patent family since the expiration, but related innovations in the same class may still be patentable.
References
[1] U.S. Patent No. 5,763,426 (1998).
[2] European Patent Application No. 94401924.7 (1994).
[3] Japan Patent Application No. 1994-612341 (1994).
[4] Carcelen, F. (2015). Pharmaceutical formulation patents: A review. Journal of Patent Law, 23(4), 210–235.
