Pharmacokinetics Study Of A Novel Antitumor Drug, Tetrazanbigen

Tetrazanbigen(TNBG), a novel synthesized antitumor drug with azagonane structure, was developed by the Institute of Pharmaceutical Chemistry and Biomaterial, Chongqing Medical University. Many experiments, both in vivo and in vitro, have proved its significant antitumor effect, and novel mechanism by interfering the lipo-metabolism of tumor cell. The mechanism of TNBG is very different from that of the general antitumor drugs, which are cytotoxicity antitumor drugs. Therefore, it is essential to do some further research on its analysis method and the research about its metabolism and pharmacokinetics in vivo.The application of drug metabolism and pharmacokinetics principles to drug design is a new concept. Pharmacokinetics includes absorption, distribution, metabolism and excretion of the drug in vivo. Especially, drug metabolism study is very important in development of a new drug. To get the message of the metabolic pathway, and identify, whether or not, mediated by CYP enzymes before the drug fit into clinical application, are very necessary to instruct the safe and rational administration.The aim of this work is to investigate the pharmacokinetics and metabolism of such a novel drug by HPLC and LC/MS. The work developed in this dissertation are as follows:1. Develop a method for the determination of TNBG. TNBG is determined by a reversed phase high performance liquid chromatography method. TNBG can be quantitatively determined under such chromatographic conditions: Lichrospher C₁₈ column (4.6 mm×250 mm,5μm ) , and mobile phase: methanol-deionized water, containing 0.1 % triethyl amine,(90:10, pH 6.5, v/v) with a flow rate of 1.0 mL·min^-1, and the detection wavelength is 260nm, the column temperature is 30℃.2. Develop a method for determination of TNBG in the biological samples. TNBG can be quantitatively determined under the same chromatographic conditions as above. In the biological samples analysis, methanol acts as a deproteination reagent, all samples are processed by solid phase extraction, then measured by RP-HPLC. Over the concentration range of 2-20μg·mL^-1, the linearity, recovery and precision are all satisfied.3. The pharmacokinetics of TNBG is studied. The results show that the pharmacokinetics of TNBG in mouse plasma agrees with two-compartment model. After i.v. administration with 10mg·kg^-1, the terminate half-life of TNBG is 5.752±1.757 h, the total clearance is 1.599±0.401L·kg^-1·h^-1. The parameters of another two dosage groups (20mg·kg^-1 , 30mg·kg^-1)are similar .The distribution study of TNBG in mouse shows that TNBG can be extensively distributed. After i.v. administration with 10mg·kg^-1, the order of TNBG content in different tissues is lung, spleen, kidney, liver, brain, and heart.After i.v. administration with 10mg·kg^-1, the samples of urine, feces, and bile in mice were analyzed by HPLC. The study shows that the origin form of TNBG was mainly excreted via feces. And the metabolite of TNBG was determined by LC/MS.The ratio of plasma protein binding, studied by equilibrium dialysis, is about 88%.4. Identification of cytochrome P450 isoforms(CYP2C9, CYP2D6 and CYP3A4) involved the metabolism of TNBG in rat liver microsome. Various selective chemical inhibitiors were used to investigate their effects on the metabolism of TNBG. The study shows that TNBG is rapidly metabolized in rat liver microsomes and CYP2C9, CYP2D6 and CYP3A4 may be involved in the metabolism of TNBG.In the present study, the pharmacokinetics and the metabolism of TNBG in mice were studied by HPLC and LC/MS method. Selective chemical inhibitiors were used to investigate their effects on the metabolism of TNBG. The study shows that TNBG is rapidly metabolized in rat liver microsomes and CYP2C9, CYP2D6 and CYP3A may be involved in the metabolism of TNBG.