Inclusion criteria:

• Newly diagnosed as essential hypertension or not treated in the past 2 weeks(If the subject took medication in the past 2 weeks, a wash-out period of at least 2 weeks will be completed prior to performing screening (week -2) assessments)
• Mean seated SBP at screen visit = 130mmHg (as measured by a mercury sphygmomanometer)
• Type 2 diabetes (American Diabetes Association criteria 2004) and HbA1C <11%
• Agree to practice acceptable contraceptive measures during the study, and for 30 days after the last dose of study medication is taken if the subject a female of child-bearing potential
• Provide written informed consent

Exclusion criteria:

• Mean seated SBP of > 180 mmHg
• Known or suspected secondary hypertension
• Anemia defined by haemoglobin concentration < 10.0 g/dL
• Hemoglobinopathy or peripheral vascular disease
• Clinically significant renal or hepatic disease (i.e., subjects with serum creatinine = 2.0 mg/dL; Alanine aminotransferase, Aspartate aminotransferase, total bilirubin, or alkaline phosphatase > 2.5 times the upper limit of the normal reference range)
• Unstable or severe angina, coronary insufficiency, or any congestive heart failure requiring pharmacologic treatment
• Chronic disease requiring intermittent or chronic treatment with oral, intravenous, or intra-articular corticosteroids (i.e. only use of topical, inhaled or nasal corticosteroids is permissible)
• Female who is lactating, pregnant, or planning to become pregnant
• clinically significant abnormality identified at screening which in the judgement of the investigator makes the subject unsuitable for inclusion in the study (e.g. physical examination, laboratory tests, or electrocardiogram etc.)
• Acute or chronic metabolic acidosis or a history of diabetic ketoacidosis