A simple, sensitive and reliable gradient elution high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) method was developed for quantifying helicid in dog plasma. METHODS AND RESULTS: The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were 0.3 and 1 ng/mL, respectively. This method was validated for selectivity, linearity, accuracy and precision, extraction recoveries, matrix effects, carry-over, cross-talk, dilution integrity, stability and incurred sample reanalysis (ISR). Bioavailability and pharmacokinetic parameters of helicid in beagle dogs were researched from a two period crossover design study. After intravenous administration (i.v.), helicid had a mean (± SD) AUC0-∞ of 12062.06 ± 2482.69 ng/mL h and terminal half-life (t1/2 z) of 2.91 ± 1.37 h, while Cmax was 35613.23 ± 8157.18 ng/mL. Following intragastric gavage administration (i.g.), AUC0-∞ was 7589.16 ± 1797.20 ng/mL h along with a longer t1/2 z of 4.10 ± 4.35 h. Cmax was researched at 0.58 ± 0.20 h. The absolute bioavailability (F) of helicid was 15.74 ± 1.87%. |