Erdosteine
Erdosteine is a mucolytic. Specifically it is a thiol derivative developed for the treatment of chronic obstructive bronchitis, including acute infective exacerbation of chronic bronchitis. Erdosteine contains two blocked sulfhydryl groups which are released following first-pass metabolism. The three active metabolites exhibit mucolytic and free radical scavenging activity. Erdosteine modulates mucus production and viscosity and increases mucociliary transport, thereby improving expectoration. It also exhibits inhibitory activity against the effects of free radicals produced by cigarette smoke.