Type 2 Diabetes Patients Switched From Sulfonylurea With Metformin to Glyburide/Metformin Combination Tablet

Inclusion Criteria: * Male or female age between 20 to 75 years and were diagnosed with type-2 DM for a minimum of 4 months before baseline. * Maintain stable dose of sulfonylurea and metformin co-administered 4 months before baseline. * Consider suitable to switch from current therapeutic dose to one of the eight testing regimens. * FPG of 80-200mg/dl at screening visit * 6.5% ≦ HbA1c ≦ 9% at screening visit, and change of HbA1c ≦ 1% within 12 weeks before screening visit. * The body index must be between 18.5 and 35 Kg/m2 at screening visit. * Sign and date the Informed Consent Form Exclusion Criteria: * Renal disease or renal dysfunction (e.g. serum creatinine \> 1.5mg/dl) * Currently significant GI disorder (such as peptic ulcer or diarrhea requiring chronic medical treatment) or which may interfere with absorption of the study drugs. * History or concurrent liver disease or hepatic impairment (total bilirubin above upper normal limit, ALT or AST above 2.5 times of upper normal limit at screening visit.) * Acute or chronic metabolic acidosis, including lactic acidosis, diabetic ketoacidosis, with or without coma. * History of cardiovascular collapse (shock) or congestive heart failure (function class III to IV). * History of stroke, myocardial infarction, coronary revascularization, or arrhythmia that requires medical treatment, within past 6 months. * Having proliferative retinopathy. * Current acute infection, including systemic infection with fever and/or sepsis, or pulmonary infection, cellulitis, etc. * Having been treated with insulin during past 6 months, or treated with acarbose or glitazones with change of daily dose past 4 months. * Seriously dehydrated. * History of alcoholism (all the time or short-term heavy drinking) or drug abuse, or taking other investigational drug. * Pregnant or breast feeding women or planning a pregnancy. * Having a surgery within 4 weeks prior to entering the study or a history of cancer within five years. * Known hypersensitive to glyburide or metformin hydrochloride. * Any clinical condition or significant concurrent disease judged by the investigator to complicate the evaluation of the study treatment.