A Study to Learn About the Study Medicine Called CTB+AVP in Healthy Adult People.

The purpose of this clinical trial is to learn about the pharmacokinetics, safety and tolerability of various single- and multiple-doses of CTB+AVP in healthy adult participants. CTB+AVP is a study medicine that is being developed to treat people with complicated urinary tract infections. This study is seeking healthy adult male and female participants, 18-60 years of age, with a body weight \> 50 kg and a BMI of 17.5 to 30.5 kg/m2. Participants in Part-1 of the study will receive increasing single doses of CTB and/or AVP. Participants in Part-2 will receive increasing multiple doses of CTB+AVP three times a day for 7 days. The study team will monitor how each participant is doing with the study treatments via close monitoring in an in-patient setting. Experiences of people receiving CTB+AVP will be compared to those of people who do not. This will help determine if CTB+AVP is safe and well-tolerated at each dose of the study medicine. Participants will take part in this study for a maximum of 12 weeks for Part-1 (up to 4 weeks for screening, up to 3 weeks of taking study medicine and up to 5 weeks for safety follow-up visit) and for a maximum of 10 weeks for Part-2 (up to 4 weeks for screening, up to 1 week of taking study medicine and up to 5 weeks for safety follow-up visit). During the duration of the study, blood samples for study medicine levels, and various measures for monitoring safety such as blood samples for clinical laboratory measurements, electrocardiograms and vital sign measurements will be taken.