To evaluate the intrapulmonary pharmacokinetics (PK), including epithelial lining fluid (ELF) and alveolar macrophage (AM) concentrations, of SPR206 as well as plasma concentrations of SPR206 in healthy adult volunteers.

Inclusion Criteria:

• Non-smoker for at least 12 months prior to screening for the study
• BMI ≥ 18.5 and ≤ 32 (kg/m2) and weight between 55.0 and 100.0 kg (both inclusive)
• Medically healthy without clinically significant abnormalities as assessed by the Investigator based on screening medical history, physical examination, vital signs, 12-lead ECG, hematology, biochemistry, coagulation, and urinalysis
• Forced expiratory volume in 1 second (FEV1) of at least 80% of predicted value at screening
• Ability and willingness to abstain from alcohol, caffeine, xanthine-containing beverages or food from 48 hours prior to study drug administration until discharge from the clinical unit
• If male, must agree to use a condom and have a non-pregnant female partner of childbearing potential agree to use a highly effective method of contraception
• If female, must be of non-childbearing potential or, if female of childbearing potential, a willingness to abstain from sexual activity or agree to use a high effective method of contraception that could lead to pregnancy
• Other inclusion criteria per protocol

Exclusion Criteria:

• History or presence of significant oncologic, cardiovascular, pulmonary, hepatic, renal, hematological, gastrointestinal, endocrine, immunologic, dermatologic, vascular or neurological disease, including any acute illness or surgery within the past 3 months determined by the Investigator to be clinically relevant

• Recent history (within 6 months) of known or suspected Clostridium difficile infection

• History of seizure disorders

• Positive urine drug, alcohol or cotinine testing at screening or check-in (Day -1)

• Positive testing for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg) or hepatitis C antibodies (HCV Ab)

• Positive testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at screening or prior to first dosing

• Presence of the following symptoms at screening or within 28 days prior to screening or check-in (Day -1):

  1. Fever, chills or sweats (temperature of 38 °C / 100.4 °F or higher)
  2. Difficulty breathing
  3. Cough
  4. Sore throat
  5. New or recent loss of taste or smell
  6. Nausea, vomiting or diarrhea

• Close contact with anyone who tested positive for SARS-CoV-2 infection within 28 days prior to screening or check-in (Day -1)

• Electrocardiogram (ECG) with QTcF interval duration equal or greater than 450 msec for males and 470 msec for females

• Subjects who have any of the following abnormalities on laboratory values at screening or Check-In including:

  1. White blood cell count < 3,000/mm3, hemoglobin < 11g/dL
  2. Absolute neutrophil count ≤ 2,000/mm3, platelet count <120,000/mm3
  3. alanine aminotransferase (ALT) OR aspartate aminotransferase (AST) greater than the upper limit of normal (ULN) for the reference laboratory

• History of substance abuse or alcohol abuse

• Use of prescription medicine & tobacco/nicotine or marijuana-containing products

• A female who is pregnant or breastfeeding

• Other exclusion criteria per protocol