Pharmacokinetics of BOF-4272, a xanthine oxidase inhibitor, after single intravenous or oral administration to male mice and rats

Synthesis of Purine Analogues: Photocatalyst-Free Visible-Light-Enhanced Annulation Approach to Pyrazolo[1,5-a][1,3,5]triazine-2,4-diamines

A new photocatalyst-free visible-light-enhanced strategy for the synthesis of pyrazolo[1,5-a][1,3,5]triazine-2,4-diamines via the formation of electron donor-acceptor (EDA) complexes is reported. The in situ generated pyrazolthiourea intermediates from 1H-pyrazol-3-amines and isothiocyanates undergo formal [4 + 2] annulation with 1,1,3,3-tetramethylguanidines (TMG) to deliver the corresponding products involved in three C-N bond formations in a one-pot protocol. The formation of EDA complex from pyrazolthiourea and TMG is confirmed by UV-vis spectroscopy and ¹H NMR experiments. Moreover, this mild reaction proceeds in the absence of any external transition metals, oxidants, bases, and ligands. This efficient methodology for the synthesis of purine analogues pyrazolo[1,5-a][1,3,5]triazine-2,4-diamines provides potential synthetic applications in the field of drug research and development.

In vitro and in vivo studies on the stereoselective pharmacokinetics and biotransformation of an (S)-(-)- and (R)-(+)-pyrazolotriazine sulfoxide in the male rat

1. BOF-4272 (a pyrazolotriazine sulfoxide) is a new drug for the treatment of hyperuricemia. The pharmacokinetics and biotransformation of both BOF-4272 enantiomers were investigated in rat. 2. Plasma concentrations after intravenous or oral administration of racemic BOF-4272 to rat were significantly higher for (S)- than for (R)-BOF-4272. 3. The concentration of (S)-BOF-4272 in hepatocyte culture medium 24 h after the addition of racemic BOF-4272 was higher than that of (R)-BOF-4272. 4. Liver concentrations after oral adminstration of racemic BOF-4272 to rat were significantly higher for (R)- than for (S)-BOF-4272. Kidney concentrations were significantly higher for (S)- than for (R)-BOF-4272. 5. Hepatic biotransformation from BOF-4272 to unknown metabolites, possibly conjugates, is stereoselective. Biotransformation of both enantiomers to the sulfone metabolite by cytochrome P450 in rat liver may also be stereoselective. 6. Biotransformation of the sulfide metabolite of BOF-4272 to BOF-4272 may be stereoselective, possibly due to the stereospecificity of flavin-containing mono-oxidase and/or cyrochrome P450. 7. The stereoselectivity of plasma concentrations of racemic BOF-4272 after intravenous or oral administration appears to be due to differences in the hepatic uptake of the two enantiomers as well as the stereoselective biotransformation of the sulfide metabolite to BOF-4272 in rat liver. Biotransformation of BOF-4272 in rat liver may also be stereoselective.

Stereoselective pharmacokinetics of BOF-4272 racemate after oral administration to rats and dogs

The stereoselective pharmacokinetics of BOF-4272 enantiomers in rats and dogs was investigated by simultaneously measuring concentrations in arterial, portal, and venous plasma, the liver, and the kidney at 2 h after the oral administration of the racemic drug. The concentrations of BOF-4272 enantiomers were measured using high-performance liquid chromatography. The concentrations of the S(-) enantiomer in arterial, portal, and venous plasma were higher than those of the R(+) enantiomer in rats, but the opposite was found in dogs. In rats, absorption from the intestinal tract into the portal system was almost the same for the two enantiomers, whereas the hepatic uptake of the R(+) enantiomer was greater than that of the S(-) enantiomer. In dogs, absorption from the intestinal tract into the portal system was greater for the R(+) enantiomer than for the S(-) enantiomer, whereas hepatic uptake was comparable for the two enantiomers. The stereoselectivity of the renal uptake of BOF-4272 enantiomers had little effect on the stereoselectivity of enantiomers in the systemic circulation in both rats and dogs. The stereoselectivity in the systemic circulation of BOF-4272 enantiomers is therefore related to hepatic uptake in rats, and to absorption from the intestinal tract into the portal system in dogs.

Evaluation of the pharmacological actions and pharmacokinetics of BOF-4272, a xanthine oxidase inhibitor, in mouse liver

BOF-4272 (+/-)-8-(3-methoxy-4-phenylsulphinylphenyl) pyrazolo[1,5-a]-1,3,5-triazine-4-(1H)-one, a new synthetic anti-hyperuricaemic drug, which has a chiral centre and exists as racemates, is a potent inhibitor of xanthine oxidase/dehydrogenase in the purine catabolism pathways. The present studies using mice demonstrated that BOF-4272 was specifically distributed in the liver, which is the main organ of uric acid production. Therefore, a decrease in uric acid concentration in the liver, rather than the plasma, was identified as a pharmacological action of BOF-4272. The ratio of liver to plasma concentrations of BOF-4272 increased from 2.5 to 6.3 over time, up to 8 h after oral administration. The elimination half-life of BOF-4272 in the liver was 5-1-fold longer than that in the plasma. High concentrations of BOF-4272 were observed in the liver up to 8 h after oral administration. Furthermore, the influx of BOF-4272 into hepatocytes occurred in a temperature-dependent manner. The liver concentrations of uric acid from 1 h to 8 h after the oral administration of BOF-4272 (0.34-0.75 microg (g tissue)(-1)) were significantly lower than those in control animals (5.03-10.96 microg (g tissue)(-1)). BOF-4269 (the sulphide metabolite of BOF-4272) was the only metabolite detected in plasma or faeces after intravenous or oral administration. BOF-4269, which has no inhibitory action on the uric acid biosynthesis system, is generated by the metabolism of BOF-4272 in the intestinal tract. In conclusion, this work using the liver as the target organ has allowed us to identify the pharmacological actions of BOF-4272 in mice. The long-lasting effect of BOF-4272 in reducing levels of hepatic uric acid was consistent with the prolonged high BOF-4272 concentrations in the liver. These results also demonstrate that the mouse is a suitable animal species for evaluating the clinical pharmacology and pharmacokinetics of BOF-4272.

Biotransformation of the xanthine oxidase inhibitor BOF-4272 and its metabolites in the liver and by the intestinal flora in rat

1. BOF-4272, (+/-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazolo[1,5-a]-1,3,5-triazine-4(1H)-one), is a new drug intended for the treatment of hyperuricaemia. 2. This paper describes the detailed biotransformation of BOF-4272 and its metabolites in the liver and by the intestinal flora in rat. 3. Only the sulphoxide metabolite (M6) was detected in plasma in small amounts after the intravenous administration of M4 (hydroxy-BOF-4272) and in culture medium after the addition of M4. 4. Only M3 (the sulphide metabolite of M4) was detected in faeces, and its amount was approximately 50% of the administered dose within 1 day after the intravenous administration of M4. 5. These findings suggest that M4, which is excreted in the bile, is metabolized mainly to M3 (the corresponding sulphide of M4) by the intestinal flora in rat, whereas little M4 is metabolized to the sulphoxide (M6) in the rat liver. 6. M2, which is the demethylated form of BOF-4269, was detected in faeces after the oral administration of BOF-4272 to rat in which the common bile duct was cannulated, suggesting that BOF-4272 is metabolized to BOF-4269 and then to M2 by the intestinal flora. 7. These findings suggest that in rat the sulphoxide of BOF-4272 and its metabolites are demethylated and reduced by the intestinal flora, with other types of biotransformation occurring in the liver.

Biotransformation of BOF-4272, a sulfoxide-containing drug, in the cynomolgus monkey

BOF-4272, (+/-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazolo[1,5-a]-1,3,5-triazine-4(1H)-one), is a new drug intended for the treatment of hyperuricemia. This report describes the pharmacokinetics and detailed metabolic pathways of BOF-4272 in the cynomolgus monkey, which were investigated using the metabolites found in plasma, urine, and faeces after intravenous and oral administration. M-4 was the main metabolite in plasma after intravenous administration. M-3 and M-4 were the main metabolites in plasma after oral administration. The Cmax and AUC(0-t) of M-4 were the highest of all the metabolites after intravenous administration. The Cmax and AUC(0-t) of M-3 were the highest of all the metabolites, and those of M-4 were the second highest, after oral administration. M-4 and M-3 were the main metabolites detected in urine and faeces, respectively, after intravenous administration, with M-4 and M-3 at 47.2% in urine and 19.1% in faeces, respectively, within 120 h after administration. M-4 was the only metabolite detected in urine after oral administration, at about 5% within 120 h after administration. M-3 was detected in faeces at 17.0% within 120 h after oral administration. These results suggest that, in the cynomolgus monkey, BOF-4272 is rapidly biotransformed to a main metabolite (M-4, a sulphoxide-containing metabolite of BOF-4272) and that M-4 is mainly excreted in urine and possibly also in bile, with subsequent conversion to M-3 by the intestinal flora. It is expected that the biotransformation of BOF-4272 would be similar in healthy human volunteers.