Clinical Research Directory

Inclusion Criteria: * Male or female, aged 18-45 years * Body mass index (BMI): 19-28 kg/m² , with body weight ≥50 kg. * Pulmonary function at screening: 1. Forced expiratory volume in 1 second (FEV₁) measured/predicted \>80% 2. Forced vital capacity (FVC) measured/predicted \>80% 3. All other ventilation and diffusion parameters normal or with no clinical significance. * Participant capability: 1. Ability to communicate effectively with investigators 2. Willingness to comply with study procedures 3. Voluntary participation with acceptance of bronchoalveolar lavage (BAL) 4. Provision of written informed consent. * Reproductive planning: 1. No pregnancy, sperm/egg donation plans from signing informed consent through 28 days after last dose 2. Participant and partner must use protocol-approved contraception. Exclusion Criteria: * Hypersensitivity to cephalosporins or carbapenem antibiotics. * History or current diagnosis of respiratory system diseases. * History or current diagnosis of coagulation disorders. * Clinically significant diseases in cardiovascular, endocrine, neurological, digestive, hematological, metabolic, or psychiatric systems judged by the investigator to interfere with study outcomes. * History of smoking or positive nicotine test during screening. * Prior surgery involving pharynx, trachea/bronchi, or lungs. * Drug abuse history within 1 year prior to screening or positive urine drug screen at screening. * Alcohol intake \>14 units/week on average within 6 months prior to screening. * Participation in other clinical trials with investigational drugs/devices within 3 months prior to screening. * Blood donation/loss ≥400 mL or blood product transfusion within 3 months prior to screening. * Respiratory infections (bacterial/fungal/viral) within 2 weeks prior to screening (e.g., upper/lower respiratory tract infections). * Use of any medication/vaccination within 14 days prior to screening or planned vaccination during the study. * Clinically significant abnormalities in physical examination, 12-lead ECG, or imaging at screening per investigator's judgment. * Pregnancy, lactation, or positive serum pregnancy test at screening.