Dynamic Study On The In Vivo Oxidation-Reduction Cycles Of Polyphenols Rifampicin

Objectives: The project is intended to demonstrate the Rifampicin(RIF),a polyphenolic compound commonly used in clinical practice and with definite hepatotoxicity,to evaluate the oxidation-reduction cycle of polyphenols drugs with the characteristics of autoxidation in vitro and in vivo.Rifampicin-quinone(RIF-Q)is the major autooxidation product of rifampicin.An efficient and sensitive LC-MS method was established.Qualitative and quantitative analysis of the oxidation-reduction cycle of phenolic and quinone structures in vivo and in vitro was performed by LC-MS/MS.Methods: Investigate the stability of rifampicin in vitro and in vivo.Establish the method of qualitative and quantitative rifampicin in vitro and in vivo.By using liquid chromatography-mass spectrometry method,to study the dynamic changes of autoxidation drug rifampicin and related substances in vivo and in vitro.In rats,using different modes of administration,given rifampin and quinone rifampicin.Investigated the pharmacokinetic parameters of phenolic structure and quinone structure respectively,and discuss the pharmacokinetic parameters.Results: On the stability study shows that RIF is very unstable at room temperature,and a large number of RIF converted to RIF-Q.In the early experiment,vitamin C(Ascorbic Acid,AA)was added as a reducing agent to prevent RIF auto-oxidation to RIF-Q.However,simultaneous determination of RIF and RIF-Q revealed that excess AA resulted in the reduction of RIF-Q to RIF.Then ?-mercaptoethanol(?-Me)was used as a reducing agent to investigate the effect of different concentrations of ?-Me on the simultaneous determination of RIF and RIF-Q.It can be concluded that when the supernatant of plasma contains ?-Me at concentration of 80 ?g /ml,rifampicin has the best stability.The simultaneous determination of RIF and RIF-Q by liquid chromatography-mass spectrometry(LC-MS / MS)was established.The method was well selective with no obvious matrix effect and residual effect.At 0.05 ~ 20?g / ml,RIF and RIF-Q showed good linearity.After intragastric administration of RIF(50 mg/kg),approximately 21% of RIF was converted to RIF-Q in vivo and about 92% of RIF-Q converted to RIF under the oral administration of RIF-Q(20mg/kg)under the effect of redox enzymes.After intravenous injection of RIF(20 mg/kg),its tendency to convert to RIF-Q increased slightly(28.2%),whereas after intravenous injection of RIF-Q(10mg/kg),there was a decrease in the tendency of RIF-Q reduce to RIF,at about 65.5%.Conclusions: The ?-Me as a reducing agent can significantly increase the stability of rifampicin.Establish a liquid chromatography-mass spectrometry method for simultaneous determination of RIF and RIF-Q in rat plasma,the method is simple,rapid and has good linearity.RIF and RIF-Q undergo an oxidation-reduction cycle in vivo.After RIF was administered to rats,a very small amount of RIF was converted to RIF-Q.After RIF-Q was given,a large amount of RIF-Q was reduced to RIF.