This study investigates the safety, tolerability, and PK profile of finafloxacin as a novel fluoroquinolone and a potential therapeutic agent for lower respiratory infections such as bacterial pneumonia. A comparison of the PK profile of finafloxacin in plasma and lung ELF using different bronchoscopic ELF sampling techniques (BMS and BAL) is conducted.

Inclusion Criteria:

1. Able to provide written informed consent;

2. Age ≥18 years and ≤55 years;

3. Male or female healthy volunteer;

4. Body mass index (BMI) ≥18.0 kg/m2 and ≤30.0 kg/m2 and a body weight

   ≥48 kg and ≤100 kg;

5. Women of childbearing potential must have a negative urine pregnancy test confirmed at Screening before study enrollment, must not be breastfeeding, and must use an effective method of contraception for at least 1 month before enrollment and through 3 months following completion of the study:

   • A woman of childbearing potential is defined as any female subject who has experienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or is not postmenopausal (defined as women over the age of 50 who have been amenorrheic for at least 12 consecutive months);
   • Women who are using oral contraceptives, other hormonal contraceptives (vaginal products, skin patches, or implanted or injectable products), or mechanical products such as an intrauterine device or barrier method (diaphragm, condoms, spermicides) to prevent pregnancy, or whose partner is sterile (e.g. vasectomy) should be considered to be of childbearing potential;

6. If a male subject's sexual partner is of childbearing potential, the male subject must acknowledge that they are using an acceptable method of contraception (defined above) from the first dose of study drug until 3 months from last dosing occasion to prevent pregnancy;

7. Expectation, in the judgment of the Investigator, that the subject will complete all study activities; and

8. Willing to comply with all the study activities and procedures throughout the duration of the study.

Exclusion Criteria:

1. Known chronic medical conditions, including any respiratory condition such as asthma or chronic obstructive pulmonary disease, or cardiovascular conditions such as hypertension or coronary artery disease;
2. Prolongation of corrected QT interval (QTcB) at rest, where the mean QTcB interval is >500 msec based on triplicate ECG at Screening;
3. Use of tobacco products within 6 months of Screening;
4. Women who are pregnant or breastfeeding;
5. Receipt of any investigational medication during the last month (30 days or 5 half-lives, whichever is longer) prior to enrollment;
6. Prior exposure to finafloxacin;
7. Use of any concomitant medication (including over-the-counter drugs, vitamins, and antacids) within 7 days prior to study drug administration and during the study (acetaminophen is allowed);
8. Any disorder that may interfere with the evaluation of study drug;
9. Known hypersensitivity to finafloxacin or to any other fluoroquinolone;
10. Donated any blood, plasma, or platelets in the 3 months prior to enrollment or on more than 2 occasions within the 12 months preceding the first dose of study drug;
11. Known history of tendon rupture or tendonitis;
12. A positive urine drug screen or breath alcohol test result at Screening or enrollment;
13. Known to have viral hepatitis, or are positive for the Hepatitis B surface antigen (HBsAg) or Hepatitis C antibody, or are positive for Human Immunodeficiency Virus (HIV) antibodies;
14. Clinically significant abnormal laboratory values at Screening or enrollment;
15. Unable or unwilling, in the judgment of the Investigator, to comply with the protocol;
16. An employee of the Investigator or study site with direct involvement in the proposed study or other studies under the direction of the Investigator or study site, or a family member of the site employee or the Investigator.