[Changes in plasma pharmacokinetics and urinary excretion characteristics before and after combined administration of Ephedrae Herba-Gypsum Fibrosum].

: In this study, UPLC-MS/MS was adopted to determine the contents of five ephedrine alkaloids (Norephedrine, Norpseudoephedrine, Ephedrine, Pseudoephedrine, Methylephedrine) in plasma and urine in rats after the combined administration of Ephedrae Herba-Gypsum Fibrosum and calculate relevant pharmacokinetic parameters, in order to discuss the effect of the combined administration of Ephedrae Herba-Gypsum Fibrosum on plasma pharmacokinetics and urinary excretion characteristics. According to the results, after being combined with Gypsum, the five ephedrine alkaloids showed similar pharmacokinetic changes, such as shortened t(max), accelerated absorption rate, but reduced AUC(0-t) and V(z)/F, which may be related to the increase in urine excretion. Besides, Gypsum was added to enhance C(max) of Pseudoephedrine and prolong MRT(0-t) of Methylephedrine, so as to enhance the anti-asthmatic effect of Ephedrae Herba and resist the toxic effect of Norephedrine and Ephedrine. This study proved the scientific compatibility of Ephedrae Herba-Gypsum Fibrosum and provided a reference for studies on the prescription compatibility regularity and relevant practices.