AZIONE ANTITOSSE DEGLI ISOMERI LEVO E DESTRO DELL NEPINALONE NEI CONFRONTI DEL RACEMO NELLA CAVIA STIMOLATA CON ACIDO CITRICO

Cough is a defence mechanism for a rapid clearance of airways from mucus or foreign bodies. Cough must not be pharmacologically inhibited except when its defensive activity is reduced and its irritative acxtivity is predominant. Nepinalone chloridrate is a new alchilaminate derivative of β-tetralone which possess a non-opioid antitussive activity. This activity has been investigated in the pharmacological model of cough-induced in guinea pig by critic acid nebulization. Nepinalone is in racemic formulation so that the investigation has been extended to its L- and D-isomers. Administered doses both for racemus and isomers were 2, 4, 8 mg/kg by intraperitoneally injection 45 minutes before starting the challenge. The latency time before the first cough, the n. of coughs during the 3 min. of challenge, the n. of coughs during the 5 min. after challenge were recorded and statistically evaluated by ANOVA and Dunnett's test. Nepinalone racemus exerted a significant antitussive activity and both L- and D-isomers confirmed to possess a significant dose-correlated antitussive effect with better trend of activity for D-isomer, but not statistically significant. Since in the racemus formulation the isomer distribution is almost equal the final effect must be attributed to an algebraic sum of the single effect of the two isomers.