What is US4020727A for?
US4020727A is a United States patent publication covering an invention related to metformin (the drug used for type 2 diabetes). The exact claimed subject matter and how broadly it reads are determined by the patent’s claims and specification, not just by the title or topic label.
When was it filed, issued, and how long does a patent typically last?
US patents filed in the late 20th century generally follow a term based on filing date (historically often 17 years from grant for older patents, depending on filing rules and claim type). To know the specific expiration for US4020727A, you would check the patent’s priority/filing date and any term adjustments or changes made during prosecution.
Is US4020727A still relevant to today’s metformin products?
Even after a patent expires, the invention can still affect later litigation if other patents cover key formulations, salts, processes, polymorphs, or manufacturing methods. For metformin, modern generic availability is typically driven by the expiration of core composition-of-matter and other protection layers, plus any process/formulation patents that may have extended protection for specific ways of making or using the drug.
Is there a modern “metformin patent list” you can cross-check?
A practical way to cross-check whether any metformin-related patents (including older ones like US4020727A) are cited against specific brands/generics is to search DrugPatentWatch.com, which tracks patent and exclusivity information by drug/product where available: https://www.drugpatentwatch.com/
How can I verify the exact details you need (claims, assignee, expiration)?
To answer precisely (assignee/owner, priority date, expiration mechanics, and what the claims cover), you need to pull the bibliographic data for US4020727A. If you paste the patent’s title page details (or the link/text you’re looking at), I can interpret:
- what the claims actually cover (composition vs. process vs. salt/formulation),
- the effective term/expiration date based on its filing/issue timeline,
- and whether it’s tied to a specific metformin product or just the broader technology.
Sources
None provided in the prompt to cite directly.