Study on the Safety, Tolerability, and Pharmacokinetics of PA9159 Nasal Spray in Healthy Adult Subjects

Inclusion Criteria: * Male and female subjects aged 18 to 65 years (including upper and lower limits); * Male body weight ≥ 50 kg, female weight ≥ 45 kg, body mass index (BMI) between 19 and 26 kg/m2 (including cut-off values); * Voluntary participation and signing of informed consent. Exclusion Criteria: * Those who cannot properly use a nasal spray, cannot tolerate nasal administration, or fail nasal spray administration training; * Those with special dietary requirements who cannot adhere to a standard diet; * Those with a history of serious diseases affecting the respiratory, cardiovascular, digestive, endocrine, hematologic, immune, or nervous systems, or currently suffering from diseases of the aforementioned systems; * A history of recurrent (defined as more than once) or disseminated shingles, glaucoma, cataracts, or ocular infectious diseases; * Allergic to the investigational drug or any component of the investigational drug, or having an allergic constitution (referring to being allergic to two or more foods, drugs, or environmental substances); * Vital signs during the screening period, physical examination, nasal examination, laboratory tests (complete blood count, blood biochemistry, urinalysis, coagulation function), serum cortisol, chest X-ray, abdominal ultrasound, 12-lead electrocardiogram, and other abnormalities judged by the investigator to be clinically significant; * Those who test positive for hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab), syphilis treponemal antibody (Syphilis TP), or HIV (HIV Ag/Ab); * Exclude individuals who have frequently consumed alcohol in the past three months, defined as drinking more than 14 units of alcohol per week (1 unit = 360 mL of beer with 5% alcohol, 45 mL of spirits with 40% alcohol, or 150 mL of wine with 12% alcohol), or those who tested positive on baseline breath alcohol tests, or those unable to stop alcohol intake during the study period; * Those with a smoking history of more than 10 years, or who smoke more than 5 cigarettes per day in the 3 months prior to screening, or who cannot stop using any tobacco products during the trial, or who test positive for nicotine at baseline; * Individuals with a history of drug abuse or drug use in the past two years, or those who tested positive for drug use in baseline urine screening; * Individuals who have taken any medication (prescription drugs, over-the-counter drugs, Chinese herbal medicine, vaccines) or health supplements within the 2 weeks prior to screening or during the screening period; * Exclude individuals who have used preparations containing corticosteroids or any drugs affecting CYP3A4 enzyme activity within the 30 days prior to screening or during the screening period; * Participants who have consumed beverages or foods containing grapefruit, dragon fruit, mango, pomelo, pomegranate, papaya, or star fruit within 14 days prior to screening and during the screening period, or who do not agree to stop consuming the above foods during the trial; * Anyone who consumes any foods or beverages rich in caffeine or methylxanthines (such as coffee, tea, cola, chocolate, seafood, cocoa, animal liver, etc.) within 48 hours prior to the first use of the investigational drug, or who does not agree to stop consuming the above foods during the trial; * Individuals who have donated blood or experienced significant blood loss (≥400 mL) within the 90 days prior to screening, or who have used blood products or received a transfusion; * Participants who have taken part in other clinical studies and used study products within the 90 days prior to screening; * Individuals who have previously undergone respiratory system surgery, have had major surgery within the three months prior to screening (as determined by the investigator based on past medical history), have experienced major trauma, or plan to undergo surgery during the study period; * Difficulty with venous blood collection, or a known history of fainting at the sight of needles or blood; * Women who test positive for pregnancy or are breastfeeding; * Researchers believe there are other situations in which participation in the trial is not suitable, or the subject cannot participate in the trial due to personal reasons.