A Study of Intramuscular Sebacoyl Dinalbuphine Ester for Post-Hemorrhoidectomy Pain Management

Inclusion Criteria: * Male or female \>= 20 years of age at Screening * Scheduled to electively undergo 2 or 3-column excisional hemorrhoidectomy * American Society of Anesthesiology Physical Class 1 - 3 * Adequate clinical lab values (values of potential clinical concern are detailed in Appendix) or, if abnormal, deemed not clinically significant per the Investigator. * Ability and willingness to provide informed consent, adhere to the study visit schedule and complete all study assessments and language specific questionnaires Exclusion Criteria: * Body weight less than 40 kg. * Concurrent fissurectomy. * Subject is pregnant or breastfeeding. Women of childbearing potential must have a negative urine pregnancy test at Baseline. * Women of childbearing potential disagree to use an acceptable method of contraception (e.g., hormonal contraceptives, IUD, barrier device or abstinence) throughout the study. * History of hypersensitivity or allergy to amide-type local anesthetics, opioid, or any ingredient of the medications administered in this study. * Subject has a resting respiratory rate less than 8 per minute and blood oxygen saturation less than 90 mmHg. * Use of any NSAIDs, selective COX-2 inhibitors, opioid, acetaminophen, selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA), gabapentin, or pregabalin within three days of surgery. * Chronic use of opioid medications for more than 14 days in the last 3 months, or non-opioid pain medications more than 5 times per week before screening visit. * Use of any long-acting opioid medication within 3 days of surgery or any opioid medication within 24 hours of surgery. * Current painful physical condition or concurrent surgery requires analgesic treatment in the postoperative period. * Contraindication to epinephrine or any of the pain-control agents planned for postoperative use. * Administration of an investigational drug within the longer of 30 days or 5 elimination half-lives of such investigational drug prior to study drug administration. * Any psychiatric disorder, psychological, medical, or laboratory condition that may interfere with study assessments or compliance. * Significant medical conditions or laboratory results that may indicate an increased vulnerability to study drugs and procedures, and thus expose the subject to an unreasonable risk as a result of participating in this clinical trial. * Any clinically significant event or condition may be uncovered during surgery. * History of abuse illicit drugs, prescription medicines or alcohol within the past 2 years. * Known history of anti-HIV antibody positive * Failure to pass drug and alcohol screen.