Bioequivalence assessment of ambroxol tablet after a single oral dose administration to healthy male volunteers.

A bioequivalence study of the ambroxol hydrochloride tablets was conducted. Twenty-four healthy male Korean volunteers received each medicine at the ambroxol hydrochloride dose of 30 mg in a 2 x 2 cross-over study. There was a 1-week washout period between the doses. Plasma concentrations of ambroxol were monitored by a high-performance liquid chromatography (HPLC) for over a period of 24h after the administration. AUC(t) (the area under the plasma concentration-time curve from time 0 to last sampling time, 24h) was calculated by the linear-log trapezoidal rule method. C(max) (maximum plasma drug concentration) and T(max) (time to reach C(max)) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC(t) and C(max), and untransformed T(max). The geometric mean of AUC(t) was 495.8 ng ml(-1)h(-1) (test medication) and 468.3 ng ml(-1)h(-1) (reference medication). C(max) of 61.5 and 57.3 ng ml(-1) were achieved for the test and the reference medication, respectively. The point estimates and 90% confidence intervals for AUC(t) (parametric) and C(max) (parametric) were, in point estimate (90% confidence interval), 1.058 (0.989-1.134) and 1.073 (1.007-1.142), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value of T(max) was 0.229 (0.015-0.444). These results indicate that the two medications of ambroxol hydrochloride are bioequivalent and, thus, may be prescribed interchangeably.

Determination of ambroxol in human plasma using LC-MS/MS.

A sensitive and selective liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the quantification of ambroxol in human plasma. Domperidone was used as internal standard, with plasma samples extracted using diethyl ether under basic condition. A centrifuged upper layer was then evaporated and reconstituted with 200 microl methanol. The reconstituted samples were injected into a C(18) XTerra MS column (2.1 x 30 mm) with 3.5 microm particle size. The analytical column lasted for at least 600 injections. The mobile phase was composed of 20 mM ammonium acetate in 90% acetonitrile (pH 8.8), with flow rate at 250 microl/min. The mass spectrometer was operated in positive ion mode using turbo electrospray ionization. Nitrogen was used as the nebulizer, curtain, collision, and auxiliary gases. Using MS/MS with multiple reaction monitoring (MRM) mode, ambroxol was detected without severe interferences from plasma matrix. Ambroxol produced a protonated precursor ion ([M+H](+)) at m/z 379 and a corresponding product ion at m/z 264. And internal standard (domperidone) produced a protonated precursor ion ([M+H](+)) at m/z 426 and a corresponding product ion at m/z 174. Detection of ambroxol in human plasma was accurate and precise, with quantification limit at 0.2 ng/ml. This method has been successfully applied to a study of ambroxol in human specimens.