United States Patent 4,724,232: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,724,232, titled "Treatment of human viral infections," is a significant patent that has played a crucial role in the treatment of viral infections, particularly in the context of AIDS. This patent, granted in 1988, revolves around the use of the compound 3'-azido-3'-deoxythymidine (AZT) for therapeutic purposes.
Background
In the late 1980s, the AIDS epidemic was at its peak, and there was an urgent need for effective treatments. The discovery and development of AZT marked a pivotal moment in the fight against HIV/AIDS. This patent documents the methods and formulations for using AZT to treat individuals infected with the AIDS virus or those carrying antibodies to the virus.
Scope of the Patent
Therapeutic Use
The patent primarily focuses on the therapeutic use of 3'-azido-3'-deoxythymidine (AZT) for treating humans infected with the AIDS virus or those who have antibodies to the virus. AZT is described as an antiviral agent that inhibits the replication of the HIV virus[1][2].
Formulations and Administration
The patent details various formulations of AZT suitable for different modes of administration, including oral, rectal, nasal, topical, vaginal, and parenteral (subcutaneous, intramuscular, intravenous, and intradermal) routes. These formulations can be presented in unit dosage forms such as tablets and sustained-release capsules[1].
Claims
Key Claims
The patent includes 24 claims that outline the specific uses, formulations, and methods of preparation for AZT. Here are some of the key claims:
- Claim 1: A method of treating a human having acquired immunodeficiency syndrome (AIDS) or infected with the AIDS virus, comprising administering an effective amount of 3'-azido-3'-deoxythymidine.
- Claim 5: A pharmaceutical composition comprising 3'-azido-3'-deoxythymidine and a carrier, where the carrier is compatible with the active ingredient and not deleterious to the recipient.
- Claim 10: A method of preparing the di- and triphosphate of 3'-azido-3'-deoxythymidine, involving a four-step sequence starting from the ammonium salt of the 5'-monophosphate[1].
Patent Landscape
Prior Art and Related Patents
The patent landscape surrounding US 4,724,232 involves several related patents and prior art. For instance, other patents have also focused on the synthesis and therapeutic applications of AZT and similar compounds. The patent cites prior art related to the synthesis of nucleotides and their use in antiviral therapies[1].
International Patent Filings
The invention described in US 4,724,232 has been the subject of international patent filings. Similar patents have been filed in other countries, reflecting the global interest in this therapeutic approach. This is evident from the patent family data available through services like the Global Dossier, which provides access to related applications filed at participating IP Offices[4].
Preparation and Formulation Methods
Synthesis of AZT Phosphates
The patent provides detailed methods for preparing the di- and triphosphate forms of AZT. This involves a four-step sequence starting from the ammonium salt of the 5'-monophosphate. The process includes the use of resin columns and specific chemical treatments to achieve the desired phosphate forms[1].
Use of Carriers and Excipients
The formulations described in the patent include the use of acceptable carriers and excipients that are compatible with AZT and do not harm the recipient. The methods for preparing these formulations involve bringing the active ingredient into association with liquid or solid carriers and shaping the product into suitable dosage forms[1].
Clinical Significance
Impact on AIDS Treatment
The approval and use of AZT as described in this patent marked a significant milestone in the treatment of AIDS. AZT was the first FDA-approved drug for the treatment of HIV/AIDS, providing a crucial therapeutic option for patients at a time when the disease was highly fatal.
Long-term Effects and Subsequent Developments
While AZT was a groundbreaking treatment, its long-term use has been associated with various side effects and the development of resistance. This has led to the development of combination therapies and newer antiretroviral drugs. Despite these advancements, the principles outlined in this patent remain foundational in the field of antiviral therapy[1].
Economic and Legal Aspects
Patent Expiration and Generic Versions
The patent for AZT has expired, allowing for the production of generic versions. This has made the drug more accessible and affordable for patients worldwide. The expiration of the patent also highlights the importance of patent term management and the impact of generic competition on the pharmaceutical market.
Global Access and Intellectual Property
The global access to AZT and other antiretroviral drugs has been a subject of significant debate, particularly in the context of intellectual property rights and public health. Organizations like UNAIDS and WHO have worked to ensure that these drugs are available in developing countries, often through negotiated pricing and licensing agreements[5].
Key Takeaways
- Therapeutic Use: The patent focuses on the use of AZT for treating AIDS and related viral infections.
- Formulations and Administration: Various formulations and administration routes are described.
- Claims: The patent includes 24 claims detailing the methods, formulations, and preparation of AZT.
- Patent Landscape: The patent is part of a broader landscape involving international filings and related patents.
- Clinical Significance: AZT was the first FDA-approved drug for HIV/AIDS, marking a significant milestone in treatment.
- Economic and Legal Aspects: The patent's expiration has led to generic versions, impacting accessibility and affordability.
FAQs
What is the main compound described in US Patent 4,724,232?
The main compound described is 3'-azido-3'-deoxythymidine (AZT), an antiviral agent used to treat AIDS.
How is AZT administered according to the patent?
AZT can be administered through various routes, including oral, rectal, nasal, topical, vaginal, and parenteral (subcutaneous, intramuscular, intravenous, and intradermal) routes.
What are the key claims of the patent?
The patent includes claims related to the method of treating AIDS, pharmaceutical compositions, and methods of preparing AZT phosphates.
Has the patent for AZT expired?
Yes, the patent for AZT has expired, allowing for the production of generic versions.
What was the impact of AZT on AIDS treatment?
AZT was the first FDA-approved drug for HIV/AIDS, providing a crucial therapeutic option and marking a significant milestone in the treatment of the disease.
Sources
- US Patent 4,724,232 - Treatment of human viral infections - Google Patents
- NZ Patent 276286A - Substituted pyrimidine thio- or oxy... - Google Patents
- Patent Claims Research Dataset - USPTO
- Search for patents - USPTO
- Additional notes on government role in the... - CPTech.Org
