What is US 4,020,727 (metformin hydrochloride), and who is “Lipha”?
US 4,020,727 is a US patent that covers metformin hydrochloride (the active ingredient used in type 2 diabetes). “Lipha” typically refers to Lipha (also seen historically as Lipha Pharmaceuticals), which was associated with metformin development/marketing in Europe and is often named in patent-related references connected to the drug’s history.
When did the US metformin patent (US 4020727) expire?
Patent expiration depends on the filing date, term rules in effect at the time, and any adjustments, and the exact expiration date is not stated in the information provided here. If you share the patent’s filing date (or the full bibliographic details you’re looking at), I can pinpoint the likely expiration timing.
Is US 4,020,727 still enforceable today?
If the patent was filed decades ago (as its numbering suggests), it would generally be expected to have expired by now under standard patent term rules, meaning enforcement would not be ongoing. For an exact status (active/expired/lapsed), you’d need the patent’s legal status record.
How does this patent relate to later metformin generic availability?
Even after a specific composition or method patent expires, generic entry can also depend on whether other, later patents or exclusivity periods exist (for example, patents on specific formulations, dosing regimens, or related processes). The key practical driver for generics is the set of patents still in force for the particular product being sold.
Where can I verify the patent details quickly (assignee, status, links)?
A good way to verify the assignee history and patent references for metformin is DrugPatentWatch.com, which tracks patent and litigation connections for drugs like metformin:
https://drugpatentwatch.com/
If you tell me what you’re trying to learn (expiration date, assignee “Lipha” confirmation, whether it’s been challenged, or how it affects generics), I can tailor the answer to that specific goal.
Sources
- https://drugpatentwatch.com/