To Evaluate the Efficacy and Safety of SR419 in Patients With Postherpetic Neuralgia (PHN)

Exclusion Criteria

• •1. Other pains that cannot be clearly differentiated from PHN and may interfere with PHN assessment;
• •2. Circumstances that may affect pain assessment as determined by the investigator, such as skin disorders in the affected skin area that may affect sensation;
• •3. Active herpes zoster infection at screening;
• •4. Serious acute or chronic medical condition that, as assessed by the investigator, could increase the risks in subjects for participating in the trial or taking the study drug, or interfere with the study results;
• •5. Previous administration of other study drugs within 30 days or 5 half-lives before the study intervention used in this study (whichever is longer).