ABSTRACT
Nifedipine, a calcium channel antagonist, is metabolized mainly by CYP3A4 to dehydronifedipine. A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously determine nifedipine and dehydronifedipine in human plasma using d6-nifedipine/d6-dehydronifedipine as internal standards. After extraction from the plasma by protein precipitation, the analytes and internal standard were separated on a Hypersil Gold C18 (50 mm×2.1 mm, 1.9 μm). The mobile phase consisted of methanol and 5 mmol·L-1ammonium acetate aqueous solution (0.1% formic acid). Positive electrospray ionization was performed using multiple reaction monitoring (MRM) with transitions of m/z 347.3→254.1 for nifedipine, m/z 345.2→283.9 for dehydronifedipine, m/z 353.3→257.1 for d6-nifedipine, m/z 351.2→286.9 for d6-dehydronifedipine. The method had a linear calibration curves over the concentrations of 0.10-80.0 ng·mL-1 for nifedipine and 0.050-40.0 ng·mL-1 for dehydronifedipine. The validated LC-MS/MS method has been successfully used study pharmacokinetic interactions of apatinib (CYP3A4 inhibitor) and nifedipine (CYP3A4 substrate) in human. This clinical trial was approved by the society of ethics and conducted in the first hospital of China medical university.
ABSTRACT
OBJECTIVE@#To investigate the effects of Coriaria Sinica Maxim's extract(CSME) on microcirculation and oxidative stress of wounds in rats with deep second-degree burn.@*METHODS@#One hundred and eighty rats were randomly divided into normal saline group(NS), white petroleum group(WPL), silver sulfadiazine group (SSD), Coriariasinica Maxim's extract group which were divided into low dose(CSME-L),middle dose(CSME-M) and high dose(CSME-H). After anesthesia with burn instrument to burn the hair removal area of rats, these wounds were confirmed by pathological results with deep second degree burns.And then,those drugs were applied respectively on the wounds,such as NS、WPL、SSD and different concentrations of CSME. After injury at 48 h, 7 d, 14 d and 21 d,the healing rate(HR) of wound was measured, and the microvessel density (MVD), tissue moisture (TM), vascular endothelial growth factor (VEGF), model driven architecture (MDA), superoxide dismutase(SOD) and hydroxyproline(HYP) were detected, too. All pathological sections of the wound tissue were observed.@*RESULTS@#The HR of CSME groups were obviously increased with a dose-dependent manner, which was significantly higher than that of NS and WPL (<0.05); On the 21 day, the diameter, number, distribution of the vessels and and the TM were less than other groups with a dose-dependent manner; On the 7 and 14 day after injury, CSME groups were significantly higher than the NS, WPL and SSD with a dose-dependent manner (<0.05), but, on the 21 day after injury, they were lower than NS, WPL and SSD with a dose-dependent (<0.05) manner. The levels of SOD, HYP, NO and ET in CSME groups were higher than those in other groups with dose-dependent on SOD activity, HYP, NO and ET content (<0.05), while MDA activity was weaker than other groups (<0.05). Similarly, pathological findings were also shown that CSME groups were better than other groups with a dose-dependent manner in decrease decreasing of wound repair time and hyperplasia of scar tissue.@*CONCLUSIONS@#CSME can relieve tissue edema, promote wound contraction, speed up the formation of eschar and accelerate the proliferation of granulation tissue, which are beneficial to the wound healing in the early stages. But, it can inhibit the hyperplasia of granulation tissue to prevent the excessive scar hyperplasia of burn wound in the later stages. Its mechanism is related to regulation what microcirculation, oxidativestress, NO and VEGF.