To establish an HPLC method to determine osimertinib mesylate,Agilent ZORBAX Eclipse Plus C18 column (4.6 mm × 250 mm,5 μm) was used with a mobile phase consisting of methanol-buffer solution (20 mmoL/L NaH2PO4,pH 3.0 adjusted with 85％ H3PO4) (50 ∶ 50) at the flow rate of 1.0 mL/min.The detection wavelength was 210 nm,and the column temperature was kept at 35 ℃.The calibration curve was liner over the range from 50％ to 150％ of determination concentration (0.201 1-0.603 2 mg/mL,r =0.999 9).The limit of quantitation (LOQ) and limit of detection (LOD) were 0.32 μg/mL and 0.08 μg/mL,respectively.The contents of osimertinib mesylate in samples were 100.1％,99.5％ and 99.7％.Good chromatographic separation of osimertinib mesylate and its related substances,including synthetic impurities and degradation products,were obtained.The established HPLC method is specific,accurate,simple and durable,and could be used for the determination of osimertinib mesylate.

Objective:To investigate the epidemiological characteristics of lower extremity deep vein thrombosis (DVT) in patients with femoral fracture.Methods:Retrospectively analyzed were the data of 2,571 patients with femoral fracture who had been treated at the Third Hospital of Hebei Medical University from January 2019 to December 2019. There were 1,079 males and 1,492 females, aged from 14 to 96 years (average, 67.1 years). There were 1,158 femoral neck fractures, 951 femoral intertrochanteric fractures, 309 femoral shaft fractures, and 153 femoral condylar fractures. 2,414 patients were treated surgically while 157 patients non-surgically. Color Doppler ultrasonography of both lower extremities was performed to determine the occurrence of DVT before operation and every week after operation for patients undergoing surgical treatment, and within 48 hours after admission and every week during hospitalization for those undergoing non-surgical treatment. The incidence and location of DVT were recorded for different femoral fractures.Results:The incidence of DVT in this cohort was 35.5%(913/2,517), that of proximal DVT 5.3%(135/2,571), and that of distal DVT 30.3% (778/2,571). In patients with femoral neck fracture, femoral intertrochanteric fracture, femoral shaft fracture and femoral condylar fracture, the incidence of DVT was respectively 28.8% (334/1,158), 44.7% (425/951), 30.7% (95/309) and 38.6% (59/153), the incidence of proximal DVT was respectively 2.7% (31/1,158), 5.6%(53/951), 9.7% (30/309) and 13.7% (21/153), and the incidence of distal DVT was respectively 26.2% (303/1,158), 39.1% (372/951), 21.0% (65/309) and 24.8%(38/153). The incidence of DVT in the femoral vein and above, popliteal vein, tibiofibular vein and intermuscular vein in this cohort was respectively 2.3%(60/2,571), 2.9%(75/2,571), 6.4%(165/2,571) and 23.8%(613/2,571).Conclusions:The incidence of DVT may be high in patients with femoral fracture, and the proximal DVT with a high risk of pulmonary embolism may occur more in patients with femoral condylar fracture.