Clinical Study Design~- In this clinical study, Part 1 is conducted as a preliminary study on 10 subjects at a single center, and based on the results of Part 1, the sponsor and the principal investigator determine whether to proceed with Part 2. With Part 2 as the multicenter main study conducted on the remaining 70 subjects, 80 subjects in total have been planned for Part 1 and Part 2.~Interim analysis~- The interim analysis is conducted when the study on 10 subjects at a Part 1 single center has been completed; the analysis is made on all endpoints planned for this clinical study.~Clinical study methods - During screening, subjects who have voluntarily signed the Informed Consent Form are tested for eligibility to this clinical study.~After a wash-out period of at least two weeks, subjects who satisfy the inclusion/exclusion criteria are randomly assigned to two groups (S-amlodipine group, Amlodipine group). Thereafter, the subjects are enrolled and orally administered with the investigational product once a day for 12 weeks, during which they receive a total of five visits for tests conducted for assessment of efficacy and safety.~(In case of confirmed eligibility without administration of contraindications, the wash-out period may be omitted and Visits 1 and 2 may be paid on the same day)
As a third-generation dihydropyridine calcium channel blocker (CCB), Amlodipine is mainly used in a single therapy or combined therapy for hypertension or angina.~Edema, one of the most common side effects of dihydropyridine CCB formulations, may lead to drug control or discontinuation of drugs.~This clinical study intends to assess the safety and efficacy of S-amlodipine, which is assessed to be superior to Amlodipine in the aspects of antihypertensive effect and side effects, in edema of patients with essential hypertension.