Selective inhibitor of the Rho-associated protein kinase p160ROCK. Ki values are 0.14, 26, 25 and >250 µM for p160ROCK, PKC, cAMP-dependent protein kinase and myosin light-chain kinase, respectively. Prevents apoptosis as well as enhance the survival and cloning efficiency of dissociated human embryonic stem cells (hES) without affecting their pluripotency.