RESUMEN
AIM: To establish a method for quantitation of cefepime and avibactam in M-H broth, and applicated in the in vitro dynamic PK/PD model. METHODS: The cefepime was also determined using the high-performance liquid chromatography method (HPLC), the avibactam was also determined using the liquid chromatography-mass spectrometry (LC-MS/MS), an in vitro dynamic PK/PD model was established to study the PK/PD relationship of cefepime/avibactam against carbapenem resistant Klebsiella pneumoniae (CRKP). RESULTS: The linear ranges of cefepime and avibactam were good at (0.5-20) and (0.1-25) μg/mL (r=0.999), and the lower limit concentrations were 0.5 and 0.1 μg/mL. The extraction recoveries of cefepime and avibactam in M-H broth were 88.0%-101.7% and 90.9%-95.2%, the relative standard deviation of intra-day precision and inter-day precision were less than 5.2%. The concentration-time curves were well simulated by the PK/PD model. All observed concentrations in each experiment were in the range of 20% of the targeted values. For the CRKP of MIC=8 μg/mL and MIC=16 μg/mL, the colony decreased to 2.783Log10 CFU/mL and 1.325Log10 CFU/mL at the cefepime/avibactam 2.5 g q8 h administration after 24 h. CONCLUSION: The determination method of cefepime and avibactam in broth established in this study has high sensitivity and good stability. For the CRKP with MIC≤8 μg/mL,cefepime/avibactam showed that good anti-CRKP activity under routine administration in vitro dynamic PK/PD model.
RESUMEN
A Helmholtz coil is selected to generate the alternating magnetic field,and the relevant model is established with a rat brain tumor as the research object.Based on the Pennes bioheat transfer equation,the electromagnetic field distribution and temperature field distribution are calculated in COMSOL simulation software,and the factors affecting the outcome of magnetic induction hyperthermia are analyzed.The results show that both magnetic field distribution and temperature field distribution meet the requirements for magnetic induction hyperthermia.The magnetic field distribution in the tumor treatment area is uniform,and the central magnetic induction strength is 12.847 mT.The temperature rise in the tumor area is significant,and the temperature at the tumor center is 46℃or above,basically reaching the treatment temperature.The therapeutic efficacy of magnetic induction hyperthermia is affected by the number of turns,current,radius and spacing,magnetic field frequency and other parameters.The study provides reference for the clinical application of magnetic induction hyperthermia and the coil design.