Various QSAR studies for chymase inhibitors have also been performed. The QSAR analysis of anhydride-type chymase inhibitors showed that aromatic substituents played an important role in determining the inhibitory potency of the compounds [55] . While, Hayashi and coworkers showed that introduction of various substituents in chloromethyl ketone derivatives resulted in a variation in their activity against human chymase [18] . A 3D QSAR model for the identification of stable chymase inhibitors has also been developed by Yuuki et al. 2003 [56] .