Urinary tract infections (UTIs) are the second most common bacterial infection with high recurrence rates. A major causative agent of UTIs is uropathogenic Escherichia coli (UPEC), which can form persistent biofilms on urothelial surfaces and/or urinary catheters. Biofilms are inherently tolerant to antimicrobials, making them difficult to eradicate. Ciprofloxacin hybrids functionalised with nitroxides have previously shown enhanced biofilm eradication activity in vitro. Here, we evaluate a ciprofloxacin di-nitroxide hybrid (CDN11), previously reported to have antibiofilm activity against UPEC, as a potential UTI therapeutic in various infection models. We report potent CDN11 activity against mature biofilms formed by cystitis strain UTI89 inside polyethylene catheters. In infected human bladder cell monolayers, CDN11 afforded a 3-log reduction in UPEC colony forming units (CFU) compared to controls, including intracellular bacteria. Infected mouse bladders carrying biofilm-like intracellular UPEC reservoirs had reduced bacterial burdens following treatment with CDN11 ex vivo. Activity trends for CDN11 were comparable throughout all models, indicating that our testing pipeline was robust. New antimicrobial development is arduous and requires large investments of time and money. The pipeline described here could be readily used in testing new compounds, fast tracking the development of novel UTI therapeutics.