Bioequivalence Of Tolfenamic Acid Injection In Dogs

Tolfenamic Acid is a kind of widely used non-steroidal anti-inflammatory dr?gs(NSAID),has strong anti-inflammatory effects.On the h?man body,it is mainly used to treat arthritis,migraine headaches and other diseases such as gout,slippery bursa phlogistic and dysmenorrhea etc.Not only as a pet medicine used for dogs,cats to relieve joint inflammation and pain,but also can adjuvant therapy dogs and cattle upper respiratory tract diseases.So the Tolfenamic Acid has very broad application prospects in veterinary clinic.On the basis of establishing a simple,rapid and accurate method for determination of the content of Tolfenamic acid in dog plasma,by studying the pharmacokinetic characteristics of the domestic and abroad Tolfenamic Acid,getting the pharmacokinetic parameters and analyzing bioequivalence to determine whether they have clinical substitutability.1.HPLC method for determinination of tolfenamic acid in plasma of dog.Chromatographic conditions:the analytical column was a Agilent ZORBAX Eclipse Plus C18(250×4.6 mm,5?m).The mobile phase consisted of a mixture of methanol:acetonitrile:0.05 M sodi?m acetate(pH 4.6)= 4.6:36.5:27.Flow rate:0.7 mL min-1;The col?mn temperature was 35? and the detection wave length was set at 290 nm.The velocity was 0.7 mL/min and injection vol?me 20 ?L.A good linear correlation was observed within the range of 0.05?10.0 pg/mL for tolfenamic acid(R2>0.99),the minim?m detection limit was 0.025 ?g/mL,limiting of quantitation was 0.05 ?g/mL;The average recovery(0.05,1 and 5 ?g/mL)was 85%.Within-run and between-run analysis less than 11%and 6%respectively.This article specifies the method of extracting and purificating tolfenamic acid in dog plasma,suitable for the determination of tolfenamic acid content in dog plasma2.The pharmacokinetics and bioequivalence of two kinds of tolfenamic acid injections in healthy dogsTwenty adult dogs(10?+10?)which have the same weight were divide into two groups,using cross experiment design.The first stage:1-10 dogs single dose(0.1 mL/kg bw)intramuscular inject test Tolfenamic acid injection,11-20 dogs single dose(0.1 mL/kg bw)intramuscular inject reference Tolfenamic acid injection;The second stage:1-10 dogs single dose(0.1 mL/kg bw)intramuscular inject Tolfenamic acid reference injection,11-20 dogs single dose(0.1 mL/kg bw)intramuscular inject tested Tolfenamic acid injection;Two phase dosing interval of 2 weeks and according to the scheduled time to collect blood samples.The concentrations of Tolfenamic acid in blood plasma were determined by high performance liquid chromatography(HPLC)method after administration and its pharmacokinetic parameters were obtained by Winnonlin6.3 software.The bioequivalence of test and reference products were tested by using a Bioavailability program package(BAPP)software.The main pharmacokinetic parameters of reference substance were as follows after oral administration as above in dogs.The mean T1/2,Tmax,Cmax,AUC0-t,AUC0-? and MRT of the reference Tolfenamic acid were respectively 14.52 h,0.3 h,5.38 ?g/mL,12.28 ?g·h·mL-1,13.85?g·h·mL-1,13.58 h;The mean T1/2,Tmax,Cmax,AUC0-t,AUC0-? and MRT of the test Tolfenamic acid were respectively 13.53 h,0.2 h,5.12 ?g/mL,12.1 ?g·h·mL-1,13.38 ?g·h·mL-1,13.43 h,and the relative bioavailability(F)was 101.7%.The main pharmacokinetic parameters(AUC0-t,AUC0-?,Cmax,Tmax)of reference and test have no significant difference,(p>0.05).The test with the reference of Cmax after logarithmic transformation ratio of 95%confidence interval of 86.61%?115.34%;The test with the reference of AUC0-t after logarithmic transformation ratio of 95%confidence interval of 90.12%?108.31%,Tolfenamic acid injection intramuscular absorb quickly,on the basis of bioequivalence evaluation standard two kinds of the Tolfenamic acid injections are biological equivalent,they can replace each other clinical.