Pharmacokinetics Of FNC In Beagle Dogs And Its Tissue Distribution In Rats

FNC (2’-deoxy-2’-β-fluoro-4’-azidocytidine) is a novel cytidine analogue whichis designed and developed by the scientists in the college of Chemistry and MolecularEngineering, Zhengzhou University. Recent pharmacodynamics and toxicologystudies have demonstrated that FNC has highly potent anti-tumor and anti-virusactivity and low toxicity. FNC has good anti-tumor activities for liver cancer, gastriccancer and sarcoma in vivo[1,2]. In addition, it has effective anti-HIV activity andinhibit the activities of hepatitis B virus (HBV)[3-5]. So it is worth further developingas an anti-tumor and anti-virus drug.The preclinical pharmacokinetics of FNC studies the dynamic laws of the drugin animals，which plays an important role in the research and development of FNC，the evaluation of drug preparation，provides evidences for guiding reasonable clinicalmedicine application. There have been some preliminary studies about thepharmacokinetics of FNC in our laboratory, including the plasma pharmacokinetics ofFNC in rat after single oral; its plasma protein binding and excretion of the parentdrug from urine and feces in rats. These studies showed that FNC in rats were best fitted to one-compartment model, good absolute bioavailability of orally given FNCtablet in rats and met the characteristics of linear pharmacokinetics within theeffective dose range. Furthermore, FNC in rats had a low plasma protein binding ratioand the excretion of the parent compound in urine and feces was high, indicating thatFNC had rapid absorption and widely distribute in vivo, the major excretion form ofFNC was its parent compound. In the present study, the pharmacokineticcharacteristics of FNC in experimental animals were investigated, including plasmapharmacokinetics of FNC in Beagle dogs which is non-rodent specie and tissuedistribution of FNC in rats after single oral dose.The research was divided into two parts, and the contents were as follows:Part I: Pharmacokinetics of FNC in Beagle dogs1. The development and validation of quantification method for FNC in dog plasmaA sensitive LC-MS-MS method was developed and validated for thequantification of FNC in plasma samples of dog. The protein precipitation methodwith methanol was used for biological sample pretreatment. The method validationresults showed that FNC in dog plasma have a good linear relationship within therange0.5–400ng·mL-1and lowest limit of quantification was0.5ng·mL-1, extractionrecovery was more than82.7%, the intra-day and inter-day RSD was less than7.49%.The method which was acceptable, sensitive and specific was successfully applied todetermine FNC in dog plasma.2. Plasma pharmacokinetics of FNC in Beagle dogsThe LC-MS-MS method was used for the quantification of FNC in dog plasmasamples in different time after a single intragastric administration of0.05,0.1and0.2mg·kg-1to dogs. Plasma concentration-time data was analyzed by non-compartmentalmodel with DAS3.0software. As shown in results: the t1/2value were3.91±0.64,3.61±1.04,4.92±0.83h, respectively; Cmaxwere45.77±5.08,80.47±8.88,200.57±34.11ng·mL-1； the AUC0-tvalues were227.53±23.98,375.85±74.84,1061.27±233.91ng·h·mL-1. The AUC0-tand Cmaxwere positively correlated with thedose of medication (p<0.05)and there was no significant difference for T1/2among thethree dose levels (p>0.05). FNC met the characteristics of linear pharmacokinetics within the dose range of0.05-0.2mg·kg-1. The female and male dog’spharmacokinetics parameters had no significant differences.PartⅡ: Tissue distribution of FNC in ratsEstablished and validated an HPLC-MS/MS method for the analysis of tissueconcentration of FNC in rats after a single intragastric administration of0.52mg·kg-1to rats. The method validation results showed that the method which was acceptable,sensitive and specific was successfully applied to determine FNC in rat tissuesamples. The tissue distribution results showed that the concentration of FNC intissues was highest in thymus and spleen and it eliminated slowly in these tissues; theheart and liver had little and eliminated quickly; and fat, brain, medulla spinalis hadthe lowest. Concentrations in thymus and spleen reached the peak level at12h and7hpost-dose, respectively.