Inclusion Criteria:

• Normal healthy adult subjects between 20-40 years of age.
• Body weight within 80-120% of ideal body weight. Ideal body weight = (height-80)0.7

• Acceptable medical history and physical examination including:

  • Normal chest X-ray and ECG results within six months prior to Period I dosing.
  • No particular clinical significance in general disease history within two months prior to Period I dosing.

• Acceptable clinical laboratory determinations without significant deviation from normal values within two months prior to Period I dosing, which includes:

  • AST (SGOT)
  • ALT (SGPT)
  • Gama-GT
  • alkaline phosphatase
  • total bilirubin
  • albumin
  • glucose
  • BUN
  • uric acid
  • creatinine
  • total cholesterol
  • triglyceride(TG)
• Acceptable hematology within two months prior to the study, which includes hemoglobin, hematocrit, red blood cells, MCV, MCH, MCHC, white blood cells, differential white blood cells and platelets.
• Acceptable urinalysis within two months prior to the study, which includes pH, blood, glucose and protein.
• Signed the written informed consent to participate in this study.

Exclusion Criteria:

• Recent history of drug or alcohol addiction or abuse.
• A clinically significant disorder involving the cardiovascular, respiratory, renal, gastrointestinal, immunologic, hematologic, endocrine or neurologic system(s) or psychiatric disease (as determined by the clinical investigator).
• History of allergic response(s) to nalbuphine or related drugs.
• History of clinically significant allergies including drug allergies or allergic bronchial asthma.
• Evidence of chronic or acute infectious diseases.
• Any clinically significant illness or surgery during the four weeks prior to Period I dosing (as determined by the clinical investigator).
• Taking any drug known to induce or inhibit hepatic drug metabolism within one month prior to the beginning of the study.
• Receiving any investigational drug within one month prior to Period I dosing.
• Taking any prescription medication or any nonprescription medication within two weeks prior to Period I doing.
• Donating greater than 150 ml of blood within two months prior to Period I dosing or donating plasma (e.g., plasmapheresis) within 14 days prior to Period I dosing. All subjects will be advised not to donate blood for four weeks after completing the study.
• Consumption of caffeine, xanthine-containing products (i.e., coffee, tea, caffeine-containing sodas, colas and chocolate, etc.) and/or alcohol at least 48 hours prior to days on which dosing is scheduled and during the periods when blood samples are being collected.
• Any other medical reason as determined by the clinical investigator.
• Patient is pregnant or breastfeeding. Women of childbearing potential must have a negative urine pregnancy test at Baseline.