Inclusion Criteria:

Mild-to-moderate hypertension defined as a baseline mean seated DBP of greater than or equal to 95 mm Hg and less than or equal to 109 mm Hg and a baseline 24-hour ABPM mean DBP of greater than or equal to 85 mm Hg.

Exclusion Criteria:

1. Pre-menopausal women (last menstruation =1 year prior to signing informed consent) who:

   • are not surgically sterile;
   • are nursing,
   • are of child-bearing potential and are NOT practicing acceptable methods of birth control, or do NOT plan to continue practicing an acceptable method throughout the study. Acceptable methods of birth control include IUD, oral, implantable or injectable contraceptives. No exceptions will be made.
2. Night shift workers who routinely sleep during the daytime and whose work hours include midnight to 4:00 A.M.
3. Mean sitting SBP =180 mm Hg or mean sitting DBP =110 mm Hg during any visit of the placebo run-in period.
4. Known or suspected secondary hypertension (i.e., pheochromocytoma).

5. Hepatic and/or renal dysfunction as defined by the following laboratory parameters:

   • SGPT (ALT) or SGOT (AST) >2 times the upper limit of normal range,
   • Serum creatinine >2.3 mg/dL (or >203 µmol/l).
6. Bilateral renal artery stenosis, renal artery stenosis in a solitary kidney, post-renal transplant patients or patients with only one kidney.
7. Clinically relevant sodium depletion, hypokalaemia or hyperkalaemia.
8. Uncorrected volume depletion.
9. Primary aldosteronism.
10. Hereditary fructose intolerance.
11. Biliary obstructive disorders.
12. Congestive heart failure (NYHA functional class CHF III-IV).
13. Unstable angina within the past three months prior to signing the informed consent form.
14. Stroke within the past six months prior to signing the informed consent form.
15. Myocardial infarction or cardiac surgery within the past three months prior to signing the informed consent form.
16. PTCA (percutaneous transluminal coronary revascularization) within the past three months prior to signing the informed consent form.
17. Sustained ventricular tachycardia, atrial fibrillation, atrial flutter or other clinically relevant cardiac arrhythmias as determined by the investigator.
18. Hypertrophic obstructive cardiomyopathy, aortic stenosis, hemodynamically relevant stenosis of the aortic or mitral valve.
19. Patients with insulin-dependent diabetes mellitus whose diabetes has not been stable and controlled for at least the past three months as defined by an HbA1C =10%.
20. Patients who have previously experienced symptoms characteristic of angioedema during treatment with ACE inhibitors or angiotensin II receptor antagonists.
21. History of drug or alcohol dependency within 6 months prior to signing the informed consent form.
22. Chronic administration of any medications known to affect blood pressure, except medication allowed by the protocol.
23. Any investigational therapy within one month of signing the informed consent form.
24. Known hypersensitivity to any component of the formulations.
25. Any clinical condition which, in the opinion of the investigator would not allow safe completion of the protocol and safe administration of trial medication.
26. Inability to comply with the protocol.