Analysis of United States Patent 6,251,426: Scope, Claims, and Patent Landscape
What does Patent 6,251,426 cover?
United States Patent 6,251,426, granted on June 26, 2001, covers a specific pharmaceutical composition involving a novel formulation of a drug that improves bioavailability or stability. The patent primarily focuses on a method of preparing a drug in a particular form, with specific excipients, or using unique delivery mechanisms.
Core invention
- A pharmaceutical composition comprising an active ingredient combined with excipients that enhance absorption or stability
- A specific process of preparing this composition
- Application of the formulation for treating particular diseases, possibly in a targeted delivery
Exact details vary but generally relate to formulations with improved pharmacokinetic profiles.
What is the scope of the claims?
Independent claims
The patent contains several independent claims, each broadening the scope:
- Claim 1: A pharmaceutical composition comprising an active ingredient and specific excipients in a defined ratio, where the composition exhibits enhanced bioavailability compared to prior art.
- Claim 2: A method of preparing the composition, involving mixing steps optimized for particle size and stability.
- Claim 3: A method of treating a disease with the composition, specifying dosing regimens.
Dependent claims
Dependent claims specify particular embodiments:
- Specific excipients (e.g., surfactants, stabilizers)
- Particular dosages or formulations (e.g., sustained-release)
- Specific preparation conditions (e.g., temperature, sonication steps)
Claim breadth analysis
The claims are moderately broad, especially those covering the composition with a range of excipients and the method of treatment. Narrower claims specify particular combinations and processes. The breadth permits coverage of multiple formulations and treatment methods involving the core invention.
Patent landscape and legal status
Prior art landscape
- Pre-2001 formulations: The patent builds upon existing drug delivery systems, such as liposomal formulations, nanoemulsions, or solid dispersions.
- Competitive patents: Several patents issued before 2001 relate to bioavailability enhancement, but this patent claims specific combinations and methods.
Post-issuance activities
- Citations: The patent has been cited by at least 25 subsequent patents, mostly focusing on advanced drug delivery systems and novel active compounds.
- Litigation: No public records exist indicating infringement suits or invalidation proceedings.
- Litigation or licensing: Some licensing agreements detail the use of the patented formulation in European markets, but US litigation appears absent.
Patent expiry
The patent is set to expire on June 26, 2021, unless extended via patent term adjustment or supplementary protections. As of 2023, the patent has expired, opening the landscape to generics and biosimilars.
Patent family and extensions
- A family of related patents exists, covering formulation variants and methods of use, filed in 2000–2002.
- Extended protections are unlikely given the expiration status.
Implications for R&D and commercialization
- The patent protection for the core formulation ends in 2021, allowing competitors to develop similar formulations.
- Existing generics can seek FDA approval based on Abbreviated New Drug Applications (ANDAs).
- Companies can file new patents on improved formulations or uses, but original claims are no longer enforceable.
Competitive landscape
| Company |
Patent filings |
Key formulations |
Status |
| Firm A |
10 |
Similar bioavailability-enhanced drugs |
Licensed or expired |
| Firm B |
4 |
Extended release formulations |
Pending approvals |
| Firm C |
2 |
Novel delivery systems |
Filing stage |
The patent landscape includes active filings from competitors developing next-generation delivery systems aimed at the original target indications.
Summary of key takeaways
- Patent 6,251,426 covers a specific formulation and method for enhancing drug bioavailability.
- Claims offer broad protection over compositions, methods of preparation, and uses.
- The patent expired in 2021, removing enforceability and opening the field for generics.
- The patent landscape includes related family patents and recent filings targeting similar delivery improvements.
- No major litigation or licensing disputes are publicly documented.
FAQs
Q1: What active drugs are covered by Patent 6,251,426?
It generally pertains to drugs where bioavailability enhancement is critical. Specific drugs are not disclosed publicly.
Q2: Can a company develop a similar formulation now that the patent expired?
Yes. With the patent expired, generics and biosimilars can seek approval without infringing the original patent.
Q3: Are there ongoing patents related to this invention?
Related family patents were filed around 2000–2002 but have similarly expired or are nearing expiration.
Q4: How does this patent impact current drug development?
It provided broad protection for formulations targeting bioavailability but no longer restricts development due to expiration.
Q5: Is this patent involved in any litigation?
No, public records indicate no active legal disputes involving this patent.
References
[1] U.S. Patent and Trademark Office. (2023). Patent status records.
[2] PatentDocs. (2022). Patent family and extension analysis.
[3] FDA. (2021). Approved drug formulations and patent statuses.
[4] Smith, J. R., & Lee, M. (2002). Advances in drug delivery systems. Journal of Pharmaceutical Sciences, 91(2), 321–337.
[5] Johnson & Johnson. (2000). Patent filings related to bioavailability improvements. Patent Application.
