Pharmacokinetics of m-nifedipine in Beagle dogs

AimTo study the pharmacokinetics of m-nifedipine (m-Nif) in Beagle dogs. Methods The Beagle dogs were divided into two groups. m-Nif was intravenously administered to the Beagle dogs in group 1 at the dose of 0.288 mg·kg^-1, and it was orally administered to the Beagle dogs in group 2，3 and 4 at the dose of 1.152， 3.456 and 10.370 mg·kg^-1, respectively. m-Nif in plasma was detected by reversed phase high performance liquid chromatography. The pharmacokinetic parameters were calculated by 3P97 software. ResultsWhen m-Nif was intravenously administered, the plasma concentration-time curve was fit to a two-compartment model and T_1/2β was 117 min. When m-Nif was orally administered, the plasma concentration-time curve was fit to a one-compartment model. T_1/2(k_e) and C_max　were 147 min and 20 μg·L^-1; at the low dose of 1.152 mg·kg^-1. T_1/2(k_e) was 122 min and C_max was 36 μg·L^-1 at the middle dose of 3.456 mg·kg^-1. T_1/2(k_e)was 144 min and C_max was 69 μg·L^-1 at the high dose of 10.37 mg·kg^-1, respectively. ConclusionIt was showed that the speed of elimination of m-Nif was high in Beagle dogs. The absolute bioavailability of m-Nif given orally was very low.