Nicotine transdermal patch original patent expiration?

There isn’t a single “original patent expiration” for the nicotine transdermal patch. The patch is covered by a family of patents over several years, with the core transdermal nicotine delivery patents filed in the early 1980s and granted in the late 1980s to early 1990s. In the US, patent term is either 17 years from grant (older rules) or 20 years from earliest filing (post-1995), plus any term adjustments, so the core patent(s) would have expired in the late 1990s to the early 2000s (plus any extensions).

If you want a precise date, please tell me:
- the country (US, Europe, etc.), and
- the specific patent number or the product name (e.g., NicoDerm/Nicoderm CQ).

I can then look up the exact expiration dates for the main patent family.