Effects of unsymmetrical ester substituted 1,4-dihydropyridine derivatives and their optical isomers on contraction of smooth muscle.

The optical isomers of two nifedipine-like 1,4-dihydropyridine derivates have been synthesised and tested in vitro. The (-)-isomer (S-configuration of both compounds) was more potent than the racemate, which in turn was more potent than the (+)-isomer (R-configuration). The S-configuration isomers are approximately ten times more potent that nifedipine, and may represent the optimal structure and configuration for binding to and inhibiting calcium channels.