1-Aminohydantoin hydrochloride is a major metabolite of furantoin in animal tissues. It is covalently bound to tissue proteins, released from tissues under slightly acidic conditions, and can be detected by derivatization with 2-nitrobenzaldehyde to form a nitrophenyl derivative of AHD. It can be used as an assay for the determination of veterinary drug residues in meat and milk.

Finafloxacin, a fluoroquinolone antimicrobial agent from a new 8-cyano subclass, is most effective in slightly acidic environments (pH 5.0-6.0), a condition where other fluoroquinolones typically reduce in activity. It selectively targets bacterial type II topoisomerases, such as DNA gyrase and DNA topoisomerase IV, making it suitable for treating serious bacterial infections particularly in acidic contexts, including urinary tract infections (UTIs) and Helicobacter pylori infections.