This study will determine the effect of single and repeat administration of darapladib, a novel, selective, orally active inhibitor of lipoprotein associated phospholipase A2 (Lp-PLA2) currently under clinical development on the pharmacokinetics of a single oral dose of midazolam, a cytochrome P450 3A4 (CYP3A4) probe substrate. This study will investigate the inductive and inhibitory effect of darapladib on CYP3A4 metabolic pathway.