Inclusion Criteria:
1. Healthy subjects aged 18 years or older (inclusive), both male and female.
2. Male body weight ≥ 50 kg, female body weight ≥ 45 kg, and body mass index (BMI) between 19.0-26.0 kg/m² (inclusive).
3. Subjects who voluntarily sign the informed consent form, fully understand the study content, procedures, and possible adverse reactions, and are able to complete the study in accordance with the protocol requirements.
4. Normal, intact skin on the bilateral anterior thighs without damage.
5. Able to maintain good communication with the investigator and comply with all clinical trial requirements.
6. Subjects are generally in good health, or based on the investigator's clinical judgment and comprehensive consideration of the drug's characteristics, it is determined that the subject's medical history does not preclude participation in this clinical study.
Exclusion Criteria:
1. Smokers or alcohol drinkers (consuming more than 14 units of alcohol per week within 1 month prior to enrollment: 1 unit = 285 mL of beer with approximately 3.5% alcohol, or 25 mL of spirits with approximately 40% alcohol, or 100 mL of wine with approximately 10% alcohol; smoking an average of ≥ 5 cigarettes per day within 3 months prior to the first dose) and/or inability to abstain from smoking and alcohol during the trial period; or a positive alcohol breath test.
2. Use of any prescription drug (e.g., antihypertensives), any over-the-counter drug, vitamin, herbal supplement, or drug that alters liver enzyme activity within 4 weeks prior to the first dose, or use of products affecting metabolism such as grapefruit or grapefruit-containing products within 2 weeks prior to the first dose; or refusal to refrain from consuming products containing alcohol, chocolate, caffeine, poppy seeds, or xanthine-rich products from 24 hours prior to the first dose until the end of the trial.
3. Significant changes in dietary habits (e.g., dieting, binge eating) or strenuous exercise within 2 weeks prior to the first dose.
4. Special dietary requirements that prevent adherence to the unified diet.
5. Use of any drug with a long half-life that may affect this study, or participation as a subject in any drug or medical device clinical trial within 3 months prior to the first dose.
6. Blood donation or blood loss ≥ 400 mL within 3 months prior to the first dose.
7. History of food or drug allergy, or allergic constitution.
8. Any clinically significant abnormalities in physical examination, vital signs, 12-lead electrocardiogram (ECG), posteroanterior chest X-ray, or clinical laboratory test results at screening.
9. History or presence of chronic or serious diseases of the hematologic, circulatory, digestive, urinary, respiratory, nervous, immune, or endocrine systems; mental abnormalities; metabolic disorders; or any other condition that may affect the study results.
10. Positive test results for any of the following: human immunodeficiency virus (HIV) antibody, hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, or Treponema pallidum antibody (TPPA).
11. History of drug abuse or drug dependence.
12. Birthmarks, scars, tattoos, or open wounds at the administration site (bilateral anterior thighs).
13. History of allergy to amide local anesthetics or any excipient of the investigational drug.
14. History of methemoglobinemia or atopic dermatitis.
15. History of glucose-6-phosphate dehydrogenase (G6PD) deficiency (i.e., favism).
16. History of needle phobia, blood phobia, or intolerance to venipuncture, or known severe bleeding tendency.
17. Pregnant or lactating women; female subjects who had unprotected sexual intercourse within 2 weeks prior to screening; female subjects with a positive pregnancy test; subjects (or their partners) planning for fertility or sperm/egg donation during the entire trial period and within 3 months after the last dose; unwillingness to use one or more contraceptive measures during the trial and within 3 months after the last dose.
18. Poor compliance or subjects deemed unsuitable for enrollment by the investigator.
