Abstract: AIM: To establish the method to detect gefitinib by microdialysis technical in vivo.METHODS: Adopting concentration difference methods, increment method and decrement method included, the effect of flow rates , pH, medium concentration and temperature on the gefitinib's recovery were determined. Meanwhile, the stabilities of recovery and release rates were researched in vitro and in vivo. RESULTS: Measured by retrodialysis method, the recovery and release rates of gefitinib showed fine consistency. And, the recovery rate connected with pH value of perfusate and extracellular fluid's temperature in linear relation and was a fixed variable for medium concentration. Intraday recovery and release rates displayed good stability as well.CONCLUSION: Retrodialysis method is capable of monitoring the concentration of gefitinib dynamically. The results can be used in pharmacokinetics research of gefitinib in tumor.

Key words: Gefitinib, Microdialysis, Pharmacokinetics