Detailed Analysis of the Scope and Claims of United States Patent 4,374,829
Introduction
United States Patent 4,374,829, titled "Aminoacid derivatives as antihypertensives," is a seminal patent that has significantly impacted the field of antihypertensive medications. This patent, granted to Merck & Co., Inc., introduces new carboxyalkyl dipeptide derivatives that are highly effective as angiotensin-converting enzyme (ACE) inhibitors.
Background and Prior Art
The patent builds upon earlier work in the field of ACE inhibitors. Prior art, such as U.S. Pat. Nos. 4,129,571 and 4,154,960, disclosed substituted acyl derivatives of amino acids, including the clinically effective antihypertensive compound captopril. However, these prior art compounds were not dipeptide derivatives and often contained essential sulfhydryl substituents or derivatives, which are not present in the compounds described in this patent[4].
Scope of the Invention
The invention relates to carboxyalkyl dipeptide derivatives and their use as antihypertensives. These compounds are characterized by their dipeptide structure, where the N-terminus bears a carboxymethyl group that may be further substituted. The general formula for these compounds is provided, highlighting the variability in the R and R6 groups, which can be hydroxy, aryloxy, arloweralkoxy, or arloweralkylamino, among others[4].
Key Claims
The patent includes several key claims that define the scope of the invention:
- Claim 1: This claim describes the carboxyalkyl dipeptide derivatives in general terms, including their structural formula and the possible substitutions.
- Claim 2: This claim specifies the preferred compounds, including those with particular R and R6 groups that enhance potency.
- Claim 3: This claim covers the pharmaceutical compositions containing these dipeptide derivatives, including methods of preparation and administration.
- Claim 4: This claim addresses the use of these compounds as ACE inhibitors and their antihypertensive effects[4].
Pharmaceutical Compositions and Administration
The patent details the preparation of pharmaceutical compositions containing the dipeptide derivatives. These compositions can be formulated in various ways, including tablets, capsules, and injectable solutions. The patent also discusses the dosages and administration methods, highlighting that these compounds can be effective at much lower dosages compared to prior art compounds[4].
Specific Compounds and Examples
One of the specific compounds described in the patent is lisinopril, which is an N-α-[1(S)-1-carboxy-3-phenylpropyl]-L-lysyl-L-proline. This compound is particularly noted for its high potency and is currently marketed under the trademarks ZESTRIL® by AstraZeneca and PRINIVIL® by Merck & Co.[1].
Patent Landscape and Extensions
The patent has been part of the broader patent landscape related to antihypertensive medications. The original expiration date of the patent could have been extended under certain conditions, such as regulatory reviews by the FDA, as outlined in 35 U.S.C. 156(e)(1). However, specific extensions for this patent are not detailed in the available sources[2].
Impact and Clinical Significance
The compounds described in this patent have had a significant impact on the treatment of hypertension. Lisinopril, in particular, has extensive clinical experience and is widely used due to its efficacy and safety profile. The patent's contribution to the development of ACE inhibitors has been crucial in managing hypertension and related cardiovascular diseases[1].
Patent Analytics and Claim Coverage
In the context of patent analytics, the claims of this patent would be categorized and analyzed to understand their coverage and scope. Tools like Claim Coverage Matrix and Claim Charts can help in identifying which patents and claims are actively protecting the intellectual property related to these antihypertensive compounds. This analysis can also highlight gaps or opportunities in the patent landscape, aiding in future research and development[3].
Regulatory and Legal Considerations
The patent's legal status and any extensions or adjustments due to regulatory reviews are critical for understanding its current and future impact. The Uruguay Round Agreements Act (URAA) and other legal amendments can affect the patent term, making it essential to track these changes to determine the extended expiration dates of such patents[2].
Conclusion and Future Directions
The United States Patent 4,374,829 has played a pivotal role in the development of antihypertensive medications, particularly through the introduction of lisinopril and other carboxyalkyl dipeptide derivatives. Understanding the scope and claims of this patent is essential for navigating the patent landscape in this field.
Key Takeaways
- Invention Scope: The patent covers carboxyalkyl dipeptide derivatives as ACE inhibitors.
- Key Claims: Include the structural formula, preferred compounds, pharmaceutical compositions, and use as antihypertensives.
- Clinical Significance: Lisinopril and similar compounds have extensive clinical use and efficacy.
- Patent Landscape: The patent is part of a broader landscape that can be analyzed using patent analytics tools.
- Regulatory Considerations: Patent term extensions and legal amendments can affect the patent's expiration date.
Frequently Asked Questions (FAQs)
Q1: What is the main subject of United States Patent 4,374,829?
A1: The main subject is carboxyalkyl dipeptide derivatives used as antihypertensives.
Q2: Which specific compound is widely known from this patent?
A2: Lisinopril, marketed under the trademarks ZESTRIL® and PRINIVIL®.
Q3: How do the compounds in this patent differ from prior art?
A3: They are dipeptide derivatives without essential sulfhydryl substituents and have higher potency.
Q4: What is the significance of the patent's claims?
A4: The claims define the structural formula, preferred compounds, and pharmaceutical compositions, ensuring broad protection for the invention.
Q5: How can patent analytics tools help in understanding this patent?
A5: Tools like Claim Coverage Matrix and Claim Charts can help identify gaps and opportunities in the patent landscape related to these compounds.
Cited Sources
- WANG S L ET AL: "Thermal-Dependent dehydration process and intramolecular cyclization of lisinopril dihydrate in the solid state," EP1432407B2.
- United States Patent and Trademark Office: "Consolidated Listing of Patents Extended Under 35 U.S.C. 156(e)(1)," OG Date: 29 July 2003.
- Schwegman: "Patent Analytics," Intellectual Property Law.
- US4374829A: "Aminoacid derivatives as antihypertensives," Google Patents.
