Quantum chemical (MNDo)caleulations have beenused toelucidate the molecular
properties and structure - activity relationships of dihydropyridine (DHP) type
calcium antagonists. There is a good corielation between the net atomic charges on
various atoms of the 4 - phenyl ring of dihydropyridines and pharmacological activity.
.Also, activity decreases with increasing free rotation of the phenyl ring. These results
indicate that the binding of the 4 - phenyl ring to a rigid part of the receptor plays an
important part in the activity of DHP calcium antagonists