LEXINGTON, Mass.--(BUSINESS WIRE)--Critical Therapeutics, Inc. (Nasdaq: CRTX) today announced the initiation of a Phase I clinical trial to assess the safety and tolerability of an oral single dose of the R(+) isomer of zileuton in healthy subjects. R(+) zileuton combined in equal proportion with its mirror image isomer, S(-) zileuton, comprise racemic zileuton, which is the pharmaceutical ingredient in ZYFLO® (zileuton tablets) and ZYFLO CRTM (zileuton) extended-release tablets.