A Study to Evaluate the Efficacy and Safety of HR18042 Tablets in the Treatment of Postoperative Pain of Impacted Tooth.

Inclusion criteria

• 18 to 75 years old.
• Subjects must have a plan of extraction of impacted tooth.
• Subjects with moderate to severe pain (VAS score ≥ 50mm).This must be measured within a maximum of 4 hours after the end of extraction of impacted tooth.
• weight at least 45kg,and no more than 100kg.
• If a female is of child-bearing potential, she must be using highly effective methods of contraception throughout the study.
• Willingness to comply with the study procedures and requirements.
• willing and able to provide written informed consent for this study.

Exclusion criteria

• any analgesic medication other than preoperative or intraoperative anaesthetic agents within 12h before taking trial medication medication
• a longacting NSAID within 4 days,or a shortacting NSAID within 1 days prior to dosing.
• any anti-depressive medication, selective serotonin reuptake inhibitors (SSRIs), diet pills et.al. with 30 days of study entry.
• Oral surgical site combined with infection.
• Severe cardiovascular and cerebrovascular diseases.
• Severe gastrointestinal disease.
• had a history of seizures or drug or alcohol abuse.
• uncontrolled hypertension.
• significant abnormal electrocardiogram
• significant abnormal laboratory value.
• Allergic to the study drug and ingredients.
• Pregnancy, lactation or recent Pregnant plan;
• Subjects who participated in a clinical research study involving an experimental drug before 30 days of study entry.
• other conditions unsuitable for participation in the study.