Aim: To develop a capillary gas chromatographic method for the determination and pharmacokinetic study of patchouli alcohol in rat plasma after iv administration.
Methods: The drug was extracted with ethyl acetate. Eugenol was used as internal standard. The separation was carried out on a HP-5MS quartz capillary column, with high-purity nitrogen as carrier gas and flame ionization detector (FID) as detector. The column temperature was maintained at 80 degrees C for 1 min and then programmed to 200 degrees C at a rate of 15 degrees C x min(-1); it was held at 200 degrees C for 1 min, and then programmed to 290 degrees C at a rate of 60 degrees C x min(-1); the final temperature was held for 1 min. The temperature of both injector and detector was set at 290 degrees C.
Results: The standard curve was linear from 25 to 5 000 microg x L(-1) in rat plasma. The recovery of this method was from 90.0% to 110.0% with satisfactory relative standard deviation (RSD) less than 10.0%. The pharmacokinetic parameters demonstrated patchouli alcohol were consistent with the two-compartment open model and showed linear pharmacokinetics. The T1/2beta, AUC and MRT of patchouli alcohol in patchouli oil were all higher than that of patchouli alcohol.
Conclusion: This method is quick, precise and reliable. The pharmacokinetics of patchouli alcohol is different from that of patchouli alcohol in patchouli oil.