“…The pharmacokinetics of CPTs in plasma samples by HPLC with fluorescence detection has been well established (Guo et al, 2011a;Liu et al, 2008;Loh & Ahmed, 1990;Sun et al, 2004). The biological samples were prepared using relatively simple approaches such as protein precipitate with acetonitrile (ACN)/methanol (Fraier et al, 2000;Guo et al, 2003), SPE (D'Esposito et al, 2008;Fraier et al, 2000) or extraction with organic solvents using a conventional LLE (Koshkina et al, 1999;Liu et al, 2008;Sun et al, 2004;Zhao et al, 2006). However, the same sample preparation methods for plasma samples were used for tissue samples in most cases (Koshkina et al, 1999;Wu & Zhang, 2001).…”