Hydrochloric Acid Gamla Siqiong Pharmacokinetics And Tissue Distribution Study

1. The pharmacokinetics and tissue distribution of Granisetron Hydrochloride in miceAn HPLC-FLD method has been established for determination of Granisetron concentration in mice’s blood and tissue, and to study its pharmacokinetics and tissue distribution of Granisetron Hydrochloride in mice. The chromatographic separation was performed on a Inertsil CN-3 Collumn (250×4.6 mm,5μm) using phosphoric acid-triethylamine solution:acetonitrile at the ratio of 85:15 as mobile phase with a flow rate of 1.0mL·min-1.The detection wavelength wasλex=302nm and X,em=360nm. The biological samples were alkalify with sodium hydroxide firstly and then extracted with ether:dichloromethane at the ratio of 2:3. The calibration curve of Granisetron in mice’s blood was linear between 0.5～50.0 ng·mL-1, and the typical regression equation was Y=4.92×102X+8.52×102(r=0.9960). The intra-day precision were 7.28%,4.73% and 6.87%, respectively. The inter-day precision were 10.63%,13.25% and 7.10%, respectively. The recovery of extraction was more than 80%. The calibration curve of Granisetron in mice’s tissue was linear between 2～1000ng·g-1, and the regression equation was Y=2.39×102X+6.24×102(r=0.9945). The intra-day precision were 5.89%,7.02% and 4.36%, respectively.The inter-day precision were 12.87%,10.43% and 9.63%, respectively.The blood concentration of Granisetron reaches the peak between 1.40 to 1.93 h after i.g. administration to healthy mice at the dosage of 0.075,0.15 and 0.3 mg·kg-1. There had nothing to do with Tmax and dosage. Tmax were 1.83±0.26,1.83±0.26,1.67±0.26h, MRT0-t were 7.29±0.40, 7.64±0.66,7.44±0.66h, Vd/F were 6.68±2.52,8.07±4.26,7.72±3.54L·kg-1, CL/F were 0.55±0.30,0.89±0.31,0.69±0.15 L·h·kg-1, Cmax were 8.47±2.60,15.98±6.41 and 31.31±9.28 ng-mL"1 respectively; AUC0-t were 64.40±20.88,129.17±41.03 and 204.41±60.24 ng·h·mL-1 respectively. The variance of the ratio of Cmax, AUC0-t to the dose in 3 groups showed there have no significance difference with each other(P>0.05).It showed that the process of Granisetron Hydrochloride conformed to the character of linear dynamics characteristic.Granisetron Hydrochloride distributed rapidly in tissues after i.g. administration to healthy mice at the dosage of 0.15 and 0.3 mg·kg-1. It gets to the maximum concentration firstly in stomach and intestine, and then distributed into the other tissue. The concentration in stomach and intestine are the highest, which is 20-33 and 10-15 times more than blood concentration, respectively. The concentration in liver, kidney, heart, spleen and lung is 2-4,0.8-1.8,0.4-0.7, 0.6-0.9,0.4-0.6 times more than blood concentration, respectively. The concentration in brain is the lowest, which indicate that it is uneasy to pass the blood-brain barrier.2.The pharmacokinetics and bioavailability of Granisetron Hydrochloride in humanAn HPLC-FLD method has been established for determination of Granisetron Hydrochloride concentration in human plasma and to study its pharmacokinetics and bioavailability in healthy volunteers. The calibration curve of Granisetron in human plasma was linear between 0.05～5.0 ng·mL-1, and the typical regression equation was Y=1.84×105X+1.77×104, r=0.9987. The intra-day precision were 4.61%,6.29% and 4.00%, respectively. The inter-day precision were 7.62%,9.20% and 7.57%, respectively. The recovery of extraction was more than 82%.A single oral dose of 1mg Granisetron Hydrochloride test and reference preparations were administrated to 20 healthy volunteers in a randomized cross-over design to study its pharmacokinetics and relative bioavailability. Main pharmacokinetic parameters for the test and reference preparation were as follows:Tmax were 1.65±0.52 and 1.88±0.86 h, Cmax were 3.32±0.93 and 3.20±0.86 ng·mL-1, t1/2 were 5.78±1.62 and 5.46±0.97 h, Cl/F were 56.92±23.72 and 56.32±22.99 L·h-1, Vd/F were 464.13±224.16 and 447.75±218.05 L, MRT0-t were 6.49±0.88 and 6.50±0.78 h, AUC0-t were 19.46±8.07 and 19.65±7.78 ng·h·mL-1. The relative bioavailability of the test preparation was 99.80±15.30%. The main pharmacokinetic parameters were analyzed by ANOVA after log transformation. It showed that AUC0-t、AUC0-∞、and Cmax for the test and reference preparation of Granisetron Hydrochloride has no significant difference in preparations and periods, and has significant difference between individuals. Adopted two one-side test and (1-2α) confidential interval test, AUC0-t、AUC0-∞、and Cmax of test preparation both rejection the assumption of inequivalence. Cmax of test preparation was 70%-143% of reference preparation by 90% confidence interval test. AUC0-t and AUC0-∞of test preparation was 80%-125% of reference preparation by 90% confidence interval test. So the test and reference preparations were bioequivalence.