Journal of Pharmaceutical Investigation Vol. 41, No. 5, 309-315 (2011) 309 Bioequivalence Assessment of Acephyll ® Capsule to Surfolase ® Capsule (Acebrophylline HCl 100 mg) by Liquid Chromatography Tandem Mass Spectrometry Kyung-Don Nam 1 , Ji-Hyung Seo 1,2 , Sung-Vin Yim 2 and Kyung-Tae Lee 1,2† 1 College of Pharmacy and 2 College of Medicine, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul, 130-701, Korea (Received July 8, 2011·Revised October 8, 2011·Accepted October 13, 2011) ABSTRACT − A sensitive and specific liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/ MS) was developed for the analysis of ambroxol (active moiety of acebrophylline). After acetonitrile precipitation of pro- teins from plasma samples, ambroxol and the domperidone (internal standard, IS) were eluted on a C18 column. The iso- cratic mobile phase was consisted of 10 mM ammonium acetate and methanol (10 : 90, v/v), with flow rate at 0.2 mL/min. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction mon- itoring mode to monitor the m/z 379.2→264.0 and the m/z 426.2→175.1 transitions for ambroxol and the IS, respectively. Twenty four healthy Korean male subjects received two capsules (100 mg × 2) of either the test or the reference formulation of acebrophylline HCl in a 2 × 2 crossover study, this was followed by a 1week washout period between either formulation. AUC 0-t (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. C max (maximum plasma drug concentration) and T max (time to reach C max ) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were acceptable range of log 0.8 to log 1.25 (e.g., log 0.8964 - log 0.9910 for AUC 0-t log 0.8690 - log 1.0750 for C max ). The major parameters, AUC 0-t and C max met the criteria of Korea Food and Drug Administration for bioequivalence indicating that Acephyll ® capsule (test) is bioequivalent to Surfolase ® capsule (ref- erence). Key words − Liquid chromatography/tandem mass spectrometry; Ambroxol; Bioequivalence; Acephyll ® capsule, Surfolase ® capsule Acebrophylline, 1,2,3,6-tetrahydro-1,3-dimethyl-2,6-dioxo-7H- Purine-7-acetic acid with trans-4-[[(2-amino-3,5-dibromophe- nyl)methyl]amino]cyclohexanol, is an airway mucus regulator with anti-inflammatory action. The drug’s approach involves several points of attack in obstructive airway disease. The mol- ecule contains ambroxol, pharmacologically active moiety of acebrophylline, which facilitates various steps in the biosyn- thesis of pulmonary surfactant, and theophylline-7-acetic acid whose carrier function raises blood levels of ambroxol, thus rapidly and intensely stimulating surfactant production. The resulting reduction in the viscosity and adhesivity of the mucus greatly improves ciliary clearance. On a clinical level, ace- brophylline is therapeutically effective in patients with acute or chronic bronchitis, chronic obstructive or asthma-like bron- chitis and recurrence of chronic bronchitis (Pozzi, 2007). Pharmacokinetic properties of ambroxol already have been reported. After administration of two capsules of acebrophyl- line HCl (100 mg × 2) to 28 healthy Korean subjects, AUC 0-t and C max were 1635.81 ± 405.35 ng·hr/mL and 209.35 ± 50.33 ng/mL, respectively (Cho et al., 2005). And time to reach C max (T max ) was 2 hr after oral administraton (Angelo et al., 1992). Terminal elimination half- life (T 1/2 ) was approximately 8 hr (Hang et al., 2007). Renal clearance was approximately 53 mL/ min; approximately 5 - 6% of a dose was excreted unchanged in the urine (Hyundai Pharm, Co., Ltd., 1998). Previous studies have reported different methods for the quantitative detection of ambroxol in human plasma using high performance liquid chromatography with electrochemical detector (HPLC-ECD) (Cho et al., 2005; Yoo et al., 2003). However, these published methods are not ideal for phar- macokinetic work, because they are time-consuming, need complex derivative steps, and require large amount of human plasma. In addition, detection of ambroxol using liquid chro- matographic method coupled with tandem mass spectrometry (LC-MS/MS) has not yet reported. Therefore, this study estab- lished a novel quantitative method for detecting ambroxol in human plasma using LC-MS/MS. This method is not only sen- sitive and reliable but also fast and simple compared with other recently reported methods This study was conducted to deter- mine the bioequivalence of two formulations of acebrophylline † Corresponding Author : Tel : +82-2-961-0860, E-mail : ktlee@khu.ac.kr DOI : 10.4333/KPS.2011.41.5.309