Studies On Pharmacokinetic Characteristics Of Dengzhanxixin Injection

Dengzhanxixin Injection (DI), derived from the whole plants of Erigeron breviscapus (Vant.) Hand-Mazz, is one of the most frequently used and commercially available preparation of Herbal medicine in China. Traditionally, it has been widely used to promote blood circulation, activate meridians to stop pain, as well as expel the cold and relieve exterior. Modern pharmacological studies and clinical practice have demonstrated that DI possesses various biological activities including neuroprotective actions, antibacterial, antifungal activity, anti-HIV-1 effects and regulatory and preventative effect on early liver injury and so on.DI has significant efficacy in clinical, but little studied were reported. At present, there are many pharmacological effects and clinical applications investigations reported about DI, however, its pharmacokinetic characteristics of the study is relatively scarce. Flavonoids and phenolic acids are two major bioactive ingredients in DI, and exert synergistically pharmacodynamic effect. This article attempts to summarize our laboratory group’s early work and, and then investigate the pharmacokinetic characteristics of DI on the basis of literature reported, in order to provide important and necessary information for manufacturers, clinical treatment, follow-up researches and drug development.1. Simultaneous quantification of major bioactive constituents in Dengzhanxixin Injection by UPLC-MSIn this study, a rapid and comprehensive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS) method was developed for simultaneous determination of 9 major bioactive constituents in Dengzhanxixin Injection. The chromatographic separations were obtained on an Acquity UPLC BEH C18 column (50 mm ×2.1 mm I.D.,1.7 μm) by a linear gradient elution with the mobile phase consisted of A (water and 0.6% acetic acid) and B (acetonitrile and 0.6% acetic acid). The total analytical run time was relatively short(14 min). The analytes and two internal standards (ISs) were all monitored in a selected-ion reaction (SIR) mode with a negative electrospray ionization (ESI-) interface. The calibration curves of all analytes revealed good linear regression (r>0.9972) within test ranges. This method provided good precision with RSD of intra- and inter-day variation less than 1.26% and 2.51%, respectively. The validated method was then applied to quantify of the 9 major constituents in 6 batches of Dengzhanxixin Injection, and the results indicated that the established method could be considered as an improved tool for quality control of Dengzhanxixin Injection.2. Determination of plasma protein binding rate of multicomponent in Dengzhanxixin Injection To establish a detection method for determination of concentration of six major compounds in Dengzhanxixin Injection in rat plasma and to study the plasma protein binding rate. The equilibrium dialysis was carried out to determine the plasma protein binding rate of multicomponent in Dengzhanxixin Injection, the drug concentration was detected by HPLC method. The biological samples were all handled with acetic ester-extracting. The average plasma protein binding rate of six compounds at low, middle and high concentrations were as follows, respectively:caffeotannic acid was (76.94±3.72)%, caffeic acid was (91.57±0.96)%, 1,5-DCQA was (83.32±3.73)%, scutellarin was (91.66±0.71)%,3,5-DCQA was (95.73±0.67)%, 3,4-DCQA was (94.21±0.65)%. The HPLC method was first used to determine the concentration of multicomponent in Dengzhanxixin Injection.The method is simple, reliable and stable. The six major compounds in Dengzhanxixin Injection have high capacity in binding to plasma protein in rat vitro.3. Validation of an HPLC method for the simultaneous quantification of major bioactive constituents in rat plasma after administration of Dengzhanxixin InjectionA HPLC-UV method was developed and validated for the simultaneous quantification of nine bioactive constituents in rat plasma after administration of Dengzhanxixin Injection, namely neochlorogenic, chlorogenic acid, cryptochlorogenic acid, caffeic acid,1,3-DCQA, scutellarin, 3,4-DCQA,4,5-DCQA and 3,5-DCQA. All the biological samples were all handled with acetic ester-extracting, and protocatechuic aldehyde was used as an internal standard. Chromatographic separation was achieved on a Kromasil 100-5C18 Dimensions (250 mm ×4.6 mm I.D.) with the mobile phase comprised of 0.1% formic acid and acetonitrile by a linear gradient elution. The calibration curves of all analytes revealed good linear regression (r≥0.9975) within test ranges. This method provided excellent sensitivity with LOQ in the range of 0.0218-0.0901 μg·mL-1 and good precision with RSDs of intra- and inter-day variation less than 9.86% and 10.34%, respectively. The validated method was then applied for pharmacokinetic study of the 9 constituents in rat plasma after administration of Dengzhanxixin Injection.4. In vitro inhibition of cytochrome P450 activities by Dengzhanxixin InjectionTo evaluate the in vitro inhibition activities of CYP1A2, CYP2C19, CYP3A4 and CYP2E1 by Dengzhanxixin Injection. The activities of cytochrome P450 in rat S9 were measured by detecting the turnover of their cocktail substrates after treatment with Dengzhanxixin Injection in vitro by HPLC, using the N-in-one method. The turnover of theophylline, phenacetin, dapsone and were not affected by Dengzhanxixin Injection, but the turnover of omeprazole was affected by Dengzhanxixin Injection significantly (p<0.05), and the turnover of chlorzoxazone was affected by high concentrations of Dengzhanxixin Injection too. Dengzhanxixin Injection have a significant inhibition of CYP2C19 and CYP2E1 activity.