This is a single-center, randomized, double-blind, placebo-controlled Phase 1b study to evaluate the safety, tolerability, and pharmacokinetics (PK) of multiple-dose DBM-1152A inhalation solution in healthy Chinese adults. Participants will receive once-daily nebulized inhalation dosing for 7 consecutive days. Three dose levels are planned (1 mg, 2 mg, and 4 mg), with allocation to DBM-1152A or placebo within each cohort in a 4:1 ratio. Safety assessments include treatment-emergent adverse events (TEAEs), clinical laboratory tests, vital signs, physical examinations, 12-lead ECGs, ophthalmic and pupil examinations, and Holter monitoring for exploratory concentration-QTc evaluation.

This study uses a single-center, randomized, double-blind, placebo-controlled, multiple-dose design in healthy Chinese adults. Three dose cohorts are planned: 1 mg, 2 mg, and 4 mg DBM-1152A inhalation solution. In each cohort, approximately 10 participants will be randomized in a 4:1 ratio to receive DBM-1152A or matching placebo. DBM-1152A and placebo will be administered by nebulized inhalation once daily for 7 consecutive days. Dose escalation to the 4 mg cohort will proceed after safety review of the 2 mg cohort following completion of dosing and post-dose safety observation.

Inclusion Criteria:

1. Healthy male or female subjects.
2. Aged 18 to 45 years (inclusive) at screening.
3. Body weight: Male ≥ 50.0 kg, Female ≥ 45.0 kg; Body Mass Index (BMI): 19.0 - 28.0 kg/m² (inclusive).
4. Capable of understanding and providing written informed consent.
5. Able and willing to adhere to the study protocol.

Exclusion Criteria:

1. Clinically significant abnormalities in screening assessments (physical exam, vital signs, labs, chest X-ray, ophthalmology).
2. Pulmonary function: FEV1/FVC < 80% at screening.
3. Positive serology for HBsAg, HCV, HIV, or TP-Ab.
4. Clinically significant 12-lead ECG abnormalities or QTcF > 450 ms (male) / > 470 ms (female).
5. Acute or chronic oral/pharyngeal disease.
6. History or presence of significant chronic diseases of any major organ system.
7. History of specific diseases (glaucoma, constipation, BPH, urinary obstruction, epilepsy, hyperthyroidism, etc.).
8. History of short or long QT syndrome.
9. Respiratory infection within 6 weeks (lower) or 2 weeks (upper) prior to screening.
10. Major surgery within 3 months prior to screening or planned during study.
11. Hypersensitivity to study drug components or related drugs.
12. History or evidence of drug abuse or positive drug screen.
13. Excessive daily intake of tea, coffee, or caffeine (>8 cups) within 3 months prior to screening.
14. Inability to refrain from certain foods/beverages containing caffeine/xanthine/glucose.
15. Excessive alcohol consumption or positive alcohol screen.
16. Smoking ≥5 cigarettes per day within 3 months prior to screening or positive nicotine test.
17. Use of any drugs (including herbs/vitamins) within 30 days prior to screening.
18. Participation in another clinical trial within 3 months prior to screening.
19. Blood donation/loss (>400 mL) within 3 months prior to screening or planned during/after study.
20. Difficulty with venipuncture or intolerance to intravenous access.
21. History of needle or blood phobia.
22. Intolerance to inhaled administration.
23. Pregnancy, lactation, or positive pregnancy test.
24. Unwillingness to use effective contraception during and for 6 months after the study.
25. Special dietary requirements or inability to comply with standardized diet.
26. Poor compliance as judged by the investigator.
27. Any other condition considered unsuitable for participation by the investigator.

This pharmacokinetic study requires controlling for biological sex (assigned at birth) as a variable due to its potential influence on drug metabolism and exposure. Therefore, eligibility is based on sex assigned at birth (recorded as male or female), which will be verified during screening through participant-provided medical history and/or clinical assessment.

We acknowledge and respect all gender identities. Individuals whose biological sex aligns with the study's sex-based criteria are eligible to participate, regardless of their gender identity (e.g., transgender men, transgender women, non-binary, or gender-diverse individuals).

Individual participant data (IPD) will not be shared outside the sponsor organization. Data are not being made publicly available due to participant privacy and confidentiality considerations and because there is no established process for external data sharing for this study.