Steady-state bioavailability and pharmacokinetics of ambroxol and clenbuterol administered alone and combined in a new oral formulation.

Ambroxol and clenbuterol are two drugs with potential pharmacological synergy. The objective of this study was to compare the apparent bioavailabilities at steady-state of these two compounds administered alone or in combination (CHF-023). Nine healthy male volunteers participated in the study. They received 30 mg of ambroxol alone (one Fluibron tablet), or 20 micrograms of clenbuterol alone (one Spiropent tablet), or 30 mg of ambroxol plus 20 micrograms of clenbuterol in combination (one CHF-023 tablet), every 12 hours for 7 days on three separate occasions. Ambroxol and clenbuterol concentrations were measured in plasma by appropriate GC/MS methods. Pharmacokinetic parameters were calculated by non-compartmental methods and submitted to statistical comparisons. Compartmental analysis was also performed on data provided by CHF-023 treatment. It was concluded that apparent bioavailabilities of ambroxol and clenbuterol are almost identical in Fluibron and CHF-023 tablets, and in Spiropent and CHF-023 tablets, respectively, with no statistically significant differences between pharmacokinetic parameters calculated for these two drugs during different treatments, except for peak concentration of ambroxol.