疼痛是机体组织潜在或实际受损后所产生的不愉快的感觉,属于人体预警机制,而长期疼痛和过度伤害性刺激会造成机体生理功能紊乱,影响人们的正常生活,降低生活质量[1]。宽叶缬草(Valerian radix et rhizoma,VRR)为败酱科缬草属植物宽叶缬...疼痛是机体组织潜在或实际受损后所产生的不愉快的感觉,属于人体预警机制,而长期疼痛和过度伤害性刺激会造成机体生理功能紊乱,影响人们的正常生活,降低生活质量[1]。宽叶缬草(Valerian radix et rhizoma,VRR)为败酱科缬草属植物宽叶缬草Valetiana officinalis L.var.latifolia Miq.的干燥根及根茎,其性辛、苦、温,主治脘腹胀痛、风湿痹痛、腰膝酸软、失眠[2-4],民间治疗疼痛及失眠多以水煎入药主,故将宽叶缬草水提物作为研究对象。展开更多
The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution sat...The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution saturation. The results show that only ZnO solid exists in the equilibrium state in the low concentration alkali regions, and the solubility of zinc oxide is almost invariable with temperature. With the increase of alkali concentration, equilibrium solid turns from ZnO to NaZn（OH）3 suddenly, this mutation is called invariant point. The alkali concentration of the invariant points increases with increasing temperature, but the solubility of NaZn（OH）3 decreases with increasing alkali concentration at the same temperature. At the same Na2O concentration, the higher the temperature is, the higher the solubility of NaZn（OH）3 is.展开更多
Aim To assess the potential effect of quercetin （QU）, an natural plant estrogen, on CYP1A2, CYP2E1, and CYP3A2 activities in rat liver microsomes; and to identify the magnitude of inhibitory effect and the probable ...Aim To assess the potential effect of quercetin （QU）, an natural plant estrogen, on CYP1A2, CYP2E1, and CYP3A2 activities in rat liver microsomes; and to identify the magnitude of inhibitory effect and the probable inhibitory mechanism of QU. Methods QU and specific substrate were concurrently incubated, with HPLC detection of the substrate metabolites for data analysis. The magnitude of inhibitory effect of QU on CYP3A2 was compared with those of ketoconazole （Ket） and erythromycin （Ery）. The mechanism of its inhibitory effect on CYP3A2 and CYP2E1 was derived from Lineweaver-Burk plots. Results HPLC methods were in good linear relationship with r〉0.999 1. Relative standard deviations for intra-day and inter-day were〈8.4%. Recovery of each analyte in the concentrations studied was between 91.1% and 107.6 %. QU （up to 8 μmol·L^-1） showed potent induction to CYP1A2 （338.1% of the negative control）while inhibited CYP2E1 （49.2% of the negative control） and CYP3A2 （60.3% of the negative control） activity. The magnitude of inhibitory effect for QU on CYP3A2 was between those for Ket and Ery （Ket〉QU〉Ery）. QU exhibited competitive inhibition of CYP3A2 dextromethorphan N-demethylation reaction and expressed noncompetitive inhibition of CYP2E1 chlorzoxazone-6-hydroxylation reaction. Conclusion HPLC assay has been validated with precision and accuracy. QU is an effective inhibitor of several CYP isoforms. It may cause relevant drug-drug interactions with CYP3A substrates. As a plant flavonoid, QU has potential not only in molecular advantage but also in CYP450 module capability for further application in cancer chemotherapy.展开更多
The objectives of the present study were to prepare stealthy etoposide proliposomes and study the pharmacokinetics in rabbits. Blank stealthy liposomes were prepared by film dispersion method. Stealthy etoposide lipos...The objectives of the present study were to prepare stealthy etoposide proliposomes and study the pharmacokinetics in rabbits. Blank stealthy liposomes were prepared by film dispersion method. Stealthy etoposide liposomes were prepared by using the ammonium sulfate gradient loading procedure. Vacuum freeze-drying technique was used to dry stealthy etoposide liposomes. Encapsulation efficiency of stealthy etoposide proliposomes was determined by Sephadex chromatography. The morphology was observed by transmission electronic microscope. The particle size and zeta potential were measured by using electrophoretic light scattering technology. The pharmacokinetics in rabbits was evaluated by comparison with etoposide injection and conventional liposomes, respectively. Mean encapsulation efficiency of stealthy etoposide proliposomes was 83.92% ± 3.65% （n = 3）. The liposomes were round or oval. Mean particle size was （124.5 ±26.9） nm, and zeta potential was （-39.50 ±1.04） mV. Following intravenous injection administration at a dose of 1.5 mg/kg etoposide, the three kinds of etoposide preparations were fitted with the two-compartment model. T1/2 β and A UC values of stealthy etoposide proliposomes were （19.26 ± 3.16） h and （26.04 ±3.53） μg/h/mL, respectively. T1/2 β and AUC values of etoposide injection were （0.94 ± 0.21） h and （0.98 ± 0.26） μg/h/mL, respectively. T1/2β and AUC values of conventional liposomes were （7.99 ± 1.36） h and （11.65 ± 1.70） μg/h/mL, respectively. Results indicated that the stealthy etoposide proliposomes could significantly extend the duration of etoposide in blood circulation.展开更多
基金Project (2007CB613603) supported by the National Basic Research Program of China
文摘The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution saturation. The results show that only ZnO solid exists in the equilibrium state in the low concentration alkali regions, and the solubility of zinc oxide is almost invariable with temperature. With the increase of alkali concentration, equilibrium solid turns from ZnO to NaZn（OH）3 suddenly, this mutation is called invariant point. The alkali concentration of the invariant points increases with increasing temperature, but the solubility of NaZn（OH）3 decreases with increasing alkali concentration at the same temperature. At the same Na2O concentration, the higher the temperature is, the higher the solubility of NaZn（OH）3 is.
文摘Aim To assess the potential effect of quercetin （QU）, an natural plant estrogen, on CYP1A2, CYP2E1, and CYP3A2 activities in rat liver microsomes; and to identify the magnitude of inhibitory effect and the probable inhibitory mechanism of QU. Methods QU and specific substrate were concurrently incubated, with HPLC detection of the substrate metabolites for data analysis. The magnitude of inhibitory effect of QU on CYP3A2 was compared with those of ketoconazole （Ket） and erythromycin （Ery）. The mechanism of its inhibitory effect on CYP3A2 and CYP2E1 was derived from Lineweaver-Burk plots. Results HPLC methods were in good linear relationship with r〉0.999 1. Relative standard deviations for intra-day and inter-day were〈8.4%. Recovery of each analyte in the concentrations studied was between 91.1% and 107.6 %. QU （up to 8 μmol·L^-1） showed potent induction to CYP1A2 （338.1% of the negative control）while inhibited CYP2E1 （49.2% of the negative control） and CYP3A2 （60.3% of the negative control） activity. The magnitude of inhibitory effect for QU on CYP3A2 was between those for Ket and Ery （Ket〉QU〉Ery）. QU exhibited competitive inhibition of CYP3A2 dextromethorphan N-demethylation reaction and expressed noncompetitive inhibition of CYP2E1 chlorzoxazone-6-hydroxylation reaction. Conclusion HPLC assay has been validated with precision and accuracy. QU is an effective inhibitor of several CYP isoforms. It may cause relevant drug-drug interactions with CYP3A substrates. As a plant flavonoid, QU has potential not only in molecular advantage but also in CYP450 module capability for further application in cancer chemotherapy.
基金Research Projects of Heilongjiang Science and Technology Department (Grant No.GC05C31601).
文摘The objectives of the present study were to prepare stealthy etoposide proliposomes and study the pharmacokinetics in rabbits. Blank stealthy liposomes were prepared by film dispersion method. Stealthy etoposide liposomes were prepared by using the ammonium sulfate gradient loading procedure. Vacuum freeze-drying technique was used to dry stealthy etoposide liposomes. Encapsulation efficiency of stealthy etoposide proliposomes was determined by Sephadex chromatography. The morphology was observed by transmission electronic microscope. The particle size and zeta potential were measured by using electrophoretic light scattering technology. The pharmacokinetics in rabbits was evaluated by comparison with etoposide injection and conventional liposomes, respectively. Mean encapsulation efficiency of stealthy etoposide proliposomes was 83.92% ± 3.65% （n = 3）. The liposomes were round or oval. Mean particle size was （124.5 ±26.9） nm, and zeta potential was （-39.50 ±1.04） mV. Following intravenous injection administration at a dose of 1.5 mg/kg etoposide, the three kinds of etoposide preparations were fitted with the two-compartment model. T1/2 β and A UC values of stealthy etoposide proliposomes were （19.26 ± 3.16） h and （26.04 ±3.53） μg/h/mL, respectively. T1/2 β and AUC values of etoposide injection were （0.94 ± 0.21） h and （0.98 ± 0.26） μg/h/mL, respectively. T1/2β and AUC values of conventional liposomes were （7.99 ± 1.36） h and （11.65 ± 1.70） μg/h/mL, respectively. Results indicated that the stealthy etoposide proliposomes could significantly extend the duration of etoposide in blood circulation.
