Disposition and metabolism of buspirone and its metabolite 1-(2-pyrimidinyl)-piperazine in the rat.
After i.v. injection (10 mg/kg) to rats, buspirone is rapidly cleared from blood with a t1/2 (beta) or 30 min. After the same dose is given orally, the drug is not detectable in blood or brain within the limits of sensitivity of the method. The metabolite 1-(2-pyrimidinyl)-piperazine (1-PP) has a longer t1/2 than buspirone. It is present to about the same extent in rat plasma and brain after either i.v. or p.o. buspirone. Unlike buspirone, 1-PP accumulates in the brain reaching concentrations between four-and five times those in plasma. Its brain AUC is higher than that of buspirone even when buspirone is given i.v. The results suggest that 1-PP may contribute to the pharmacological effect of the parent drug.
D000818:Animals; D001711:Biotransformation; D001921:Brain / Q000378:metabolism; D002065:Buspirone / Q000031:analogs & derivatives; D006207:Half-Life; D007700:Kinetics; D008297:Male; D010879:Piperazines / Q000378:metabolism*; D011743:Pyrimidines / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
D010879:Piperazines; D011743:Pyrimidines; C037921:1-(2-pyrimidinyl)piperazine; D002065:Buspirone