A Multicenter, Randomized, Open-labeled, Cross-over, Active-controlled, Phase IV Clinical Trial to Evaluate the Preference of Formulation and the Efficacy and Safety of Renamezin and Kremezin in Pre-dialysis Patients With Chronic Renal Failure

Inclusion Criteria: * pre-dialysis patients with chronic renal failure stage * patient for holding the stable state in serum creatinine 2.0mg/dl - 5.0mg/dl of MDRD GFR 15-60ml/min/1.73m2 for 3 months before screening * patients haven't experienced dose spherical carbon adsorbent for 3months before screening * patients who were no noticeable change for 4weeks before screening and are expected to change is not needed during therapy in the therapy of chronic renal failure(type of blood pressure medication and dose -related, diet therapy) * patients spontaneously written consent to participate in this clinical trial Exclusion Criteria: * patients with passes through the digestive tract disorders * patients with uncontrolled constipation symptoms * kidney transplant patients * patients who are taking immunosuppressive drugs * patients suffering from digestive tract ulcers and esophageal varices * patients with uncontrolled hypertension * patients hospitalized with cardiovascular disease within 3 months of the screening * patients with current infections * patients who do not fulfill therapies of chronic renal failure (taking medicine and diet) as appropriate * patients with hepatic impairment (2.5 times greater than the upper limit of normal levels of AST, ALT) * uncontrolled diabetes (HbA1c \> 10 % or a fasting glucose \> 180mg / dL) * patients with malignant tumors (However, if you do not relapse within five years after completion of therapy can be registered) * pregnant women, nursing mothers * those who do not agree to a contraceptive method allowed for the possibility of pregnancy in women * patients participating in another clinical trial in addition to the current clinical trial * subjects with dependency on drugs or alcohol * subjects who took any other investigational drugs within 30 days before participating this clinical trial study * patients expected to starting the dialysis within three months * other patients deemed unsuitable tester