This is a single center, inpatient, open label pharmacodynamic study to determine the effect of 5 g and 10 g doses of Sodium Zirconium Cyclosilicate (ZS) administered once daily (qd) for 4 days on potassium and sodium excretion in healthy Chinese subjects on a standardized, low sodium and high potassium diet.

This study will be conducted at 1 study centre in Hong Kong. Approximately 22 Subjects will be screened to achieve 20 subjects completing the study. Subjects will be randomized to receive ZS 5 g or 10 g (1:1) once daily (qd) in conjunction with breakfast and will be continued with a standard diet during the ZS treatment period.

Key Inclusion Criteria:

1. Provision of informed consent prior to any study specific procedures
2. Female and/or male healthy Chinese subjects aged between 18 and 55 inclusive who reside in Hong Kong
3. Ability to have repeated blood draws or effective venous catheterization
4. Willing to consume food and beverages using a standardized daily diet containing 40 (± 10%) mEq/day sodium and 128 (± 10%) mEq/day potassium provided by the research site

Key Exclusion Criteria:

1. Participation in another clinical study with an investigational product during the last 3 months
2. Subjects who were receiving concomitant medications including vitamins, dietary supplements and herbal preparations within 2 weeks prior to Study Day 1 of the Diet Run-in Period.
3. Current and/or past history of alcohol abuse within the past year or a positive results (exceed normal range) of breath test for alcohol abuse
4. Current and/or past history of drugs abuse within the past year or a positive drug abuse screen, e. g. methylenedioxymethamphetamine, opiate, barbiturates, benzodiazepines, ketamine, cocaine, amphetamine, methamphetamine, marijuana, and methadone.
5. Plasma donation within 1 month of screening or any blood donation/blood loss >500 mL during the 3 months prior to screening.