In vivo pharmacokinetic study

Rats were fasted for 12 h with free access to water prior to the pharmacokinetic study. Twelve rats were equally randomized to two groups and were treated as followings: intravenous injection of CPA in normal saline was administrated through lateral tail vein at a dose of 1 mg/kg. An oral gavage of CPA dissolved in normal saline containing 0.5% methylcellulose solution was given to rats at a dose of 10 mg/kg. Blood samples (250 μL) were collected into a heparinized tube via the oculi chorioideae vein at 0.083, 0.167, 0.33, 0.5, 1, 2, 4, 6, 8, 12, 24 and 48 h, respectively. After centrifugation at 4000 rpm for 10 min, plasma samples were obtained and frozen at –40 °C until analysis.