Trial to Evaluate Efficacy and Safety of Combination of Diacerein and Celecoxib Administered in Patients With Knee OA

Inclusion Criteria: 1. Subjects who voluntarily consented, after listening enough explanation for this study and investigational product. 2. Adult over 50 years of age. 3. At least one of the knee pain VAS score is 40mm or more. 4. Meets the ACR(American College of Rheumatology) criteria for diagnosis. (1) Confirmation of osteophytes on radiographic inspection. (2) One or more of the following three items. ① Age\> 50 years ② Morning stiffness \<30 minutes ③ Crepitus 5. Patients who require medication for more than 12 weeks due to osteoarthritis symptoms. 6. Those who are able to follow the requirements of this clinical trial, such as being able to trace during the clinical trial period and to read and write the VAS questionnaire. 7. Those who weigh more than 40kg Exclusion Criteria: 1. Secondary knee osteoarthritis 2. Other inflammatory Knee Osteoarthritis (e.g. gout, rheumatoid arthritis, etc.) 3. Patients presenting with gastroesophageal reflux disease, peptic ulcer. 4. Helicobacter infected patients who have not been treated for eradication (recruitment if negative in re-examination after treatment). 5. Short bowel syndrome that can cause inflammatory bowel disease (ulcerative colitis, Crohn's disease) and drug absorption disorder. 6. Intestinal obstruction syndrome 7. Unexplained abdominal pain 8. ALT(Alanine aminotransferase) level of liver function test exceeded 5 times of reference range 9. Total bilirubin level exceeded 2 mg / dL 10. Serum albumin level less than 2 g / dL 11. Ascites 12. Hepatic encephalopathy 13. Hepatitis B, hepatitis C (excluding healthy carriers) or HIV positive 14. MDRD(Modification of Diet in Renal Disease) Estimated Glomerular filtration rate less than 60 mL / m2 15. Patients with hyperkalemia (over 5.5 meq / L) 16. history of asthma, acute rhinitis, nasal polyps, angioedema, urticaria or allergic reactions to aspirin or other non-steroidal anti-inflammatory drugs(including COX-2 inhibitors). 17. Malignant tumors other than basal cell or squamous cell carcinoma of the skin, CIN(Cervical Intraepitherial Neoplasia) and CIS(Carcinoma in situ) of the cervix, and intraepithelial carcinoma of other areas Within 5 years of consent date. 18. Medical history of hypersensitivity to the components of the investigational products. (The components of test drug 1 and 2, including the Rhein-based drug) 19. Patients with an allergic reaction to sulfonamide. 20. Patients with galactose intolerance, lapp lactase deficiency or glucose-galactose malabsorption. 21. Subjects who have not reached the prescribed period after receiving contraindicated medication or treatment before participation in this clinical trial. 22. Patients receiving contraindicated medication. 23. Alcohol and other drug abuse cases based on 6 months before screening. 24. Pregnant women or nursing mothers who are not willing to stop breastfeeding. 25. Female who do not fall into one or more of the following categories(In other words, only the following female can participate:) * (1) Menopause (non-therapy-induced amenorrhea of more than 12 months) Female * (2) Female infertility due to surgery (no ovaries and / or uterus) * (3) If you have sexual intercourse with only one male partner who has been confirmed to have no semen after fertilization. * (4) Female subjects who agreed to abstinence during the clinical trial period. * If the subject is assured of an abstinence throughout the trial period.(e.g. clergy) * However, intermittent abstinence (eg, contraception using ovulation period, symptothermal) or coitus interrupts is not a case of consent for abstinence. * (5) For women of childbearing age, the following methods or methods of contraception use the effective method of contraception to be used during the period of this clinical trial: * Oral contraceptive * The contraceptive patch * Intra uterine device (IUD) * contraceptive implant * contraceptive injection * intrauterine hormonal apparatus * Tubal ligation and infertility surgery 26. If 30 days have not elapsed after the date of signing of the previous clinical trial or currently participating in other clinical trials. 27. Patients who are scheduled for surgery during the clinical trial period or who have difficulties in completing the protocol during this clinical trial due to other reasons. 28. In addition to the above, other diseases that the investigator judges to be inappropriate.