Who holds the original patent for amoxicillin, and why are all Chinese versions generics?

Who holds the original patent for amoxicillin, and why are all Chinese versions generics?
Amoxicillin's originator is Amoxil, developed by UK-based Beecham, which later merged into SmithKline Beecham and eventually GlaxoSmithKline. GSK never registered Amoxil capsules for sale in China, so the domestic market consists entirely of generics. Over 240 amoxicillin capsule approvals exist locally, yet only about 50 have passed consistency evaluation for bioequivalence. Baiyunshan's Antibiotic brand was among the first to clear this hurdle, while United Laboratories' Amoxicillin and Hkpf's Amolin enjoy strong reputations. State-owned antibiotic specialists like NCPC and Lukang also produce reliable capsules. The molecule itself derives from penicillin G: replacing a hydrogen with an amino group yields ampicillin, and adding a hydroxyl to the benzene ring produces amoxicillin, which offers better oral absorption than ampicillin.