Pharmacological evaluation of S-amlodipine and nimodipine as bronchial smooth muscle relaxants in guinea Pigs: Ex-vivo study

S-amlodipine and Nimodipine, two members of the dihydropyridine calcium channel blocker family, were originally developed to treat cardiovascular disorders, and have shown significant potential in their ability to relax bronchial smooth muscle. Hence, we evaluated the anti-asthmatic potential of L-type calcium channel blocker properties of S-amlodipine and Nimodipine using guinea pig animal models.

Twenty-four healthy adult guinea pigs were divided into four groups, each group comprised 6 guinea pigs used to study acetylcholine and histamine-induced bronchospasm models. Each group of animals received normal saline, salbutamol (10mg/kg, p.o), nimodipine (40mg/kg, p.o), and S-amlodipine (1.5mg/kg, p.o) respectively for 5 days. The anti-asthmatic effect of each guinea pig was evaluated by exposing them to 0.25% histamine aerosol and 10% acetylcholine chloride, and recording the pre-convulsive dyspnea time.

The S-amlodipine demonstrated superior efficacy by significantly increasing pre-convulsive dyspnea time (PCD) compared to nimodipine in both models of bronchoconstriction. S-amlodipine and Nimodipine exhibited significant bronchial smooth muscle relaxant activity compared to the control group, although they did not perform as effectively as the salbutamol drug.

The results of our study showed that S-amlodipine and Nimodipine exhibit notable bronchial smooth muscle relaxant activity compared to the control group. However, they do not match the effectiveness of the salbutamol drug.