This is a randomized, phase 1, single-blind, placebo controlled, single-dose, study designed to evaluate the safety, tolerability, and pharmacokinetic properties of orally administered SP-333 tablets. The study will include 7 groups of 8 subjects each (6 active, 2 placebo) given a single oral dose of of SP-333 tablets or placebo. Following outpatient screening from approximately 5 to 42 days before dosing, each subject will enter the Clinical Pharmacology Unit (CPU) and will be housed from at least 48 hours, before dosing until 48 hours after dosing. Subjects will be given single dose of the study drug on the day of dosing and remain in the CPU for at least 48 hours. Subjects will return to the CPU on Days 8±1 and 15±1 for safety follow up. Safety Committee Meetings will be conducted to review safety, tolerability, and available Pharmacokinetic data from the current and previous treatment group(s), prior to dosing subsequent treatment groups. Subjects in a given treatment group are considered completers once they have completed the Day 15±1 day Follow up Visit.