OBJECTIVE To establish a method for determining the content of 11 antioxidants and their degradation products in recombinant Exendin-4-FC fusion protein injection by HPLC. METHODS The protein was precipitated with saturated ammonium sulfate. After centrifugation, the supernatant was transferred to a C18 solid phase extraction cartridge activated by methanol. Then the cartridge was eluted with 4 mL of methanol and 5 mL of ethyl acetate respectively, and the eluent was diluted with methanol-ethyl acetate(2∶3) mixed solvent and passed through a 0.22 µm PTFE hydrophobic filter. It was analyzed by HPLC and quantified by external standard method. Chromatographic conditions: Kinetex® XB-C18 100Å (100 mm×4.6 mm, 2.6 µm)column, the detection wavelength was 230 nm, the column oven was 30 ℃, the injection volume was 5 µL and the flow rate was 0.4 mL·min–1, mobile phase was 0.1% formic acid-methanol(A)-0.1% formic acid aqueous solution(B), the running time was 45 min. RESULTS The 11 target substances showed a good linear relationship in the range of 2.5−35 μg·mL–1 with R2 ≥0.99. At three different concentration(25, 10, 5 μg·mL–1) of spiked samples, the average recovery rates of 11 antioxidants ranged from 88.1% to 106.5%, with RSDs in the range of 0.10%–9.05%. The RSDs of 6 repeatable samples was 2.01%–4.77%, which of 12 intermediate precision samples was 2.58%–9.75%. The positive/inverted samples of three batches of recombinant Exendin-4-FC fusion protein injection were detected at 0 month, 3 months and 6 months(25 ℃), and the results showed that there was no antioxidant and its degradation leaching in all batches of samples at different detection points. CONCLUSION The method has good specificity, high accuracy and precision, good solution stability, high durability and can be used for the content detection of antioxidants in drugs.

In January 2021, a 48-year old patient with an extensive open fracture and an infection in left calf was treated in the Microsurgical Orthopaedic Centre, the First Affiliated Hospital of Xinjiang Medical University. After the thorough debridement and successful infection control, a large soft tissue defect (32.0 cm×25.0 cm) in the left calf was reconstructed using a 35.0 cm×8.0 cm free latissimus dorsi myocutaneous flap which also facilitated the replacement of damaged Achilles tendon. The large area of wound in anterior tibia was covered with a medium-thickness skin graft. The 13.0 cm defect of left tibial bone was reconstructed by an in situ bone lengthening from the fractured left tibia in the stage Ⅱ surgery. At the 23-month postoperative follow-up, the flap survived well, with the Achilles tendon had regained a muscle strength at grade Ⅲ. Sensation was improved to S 4 in the weight-bearing areas of left foot, with TPD of 15 mm. The fracture of the extended tibial segment healed well. Overall function of the left ankle was rated as good using the American Orthopedic Foot and Ankle Society (AOFAS) standards.

In January 2021, a 48-year old patient with an extensive open fracture and an infection in left calf was treated in the Microsurgical Orthopaedic Centre, the First Affiliated Hospital of Xinjiang Medical University. After the thorough debridement and successful infection control, a large soft tissue defect (32.0 cm×25.0 cm) in the left calf was reconstructed using a 35.0 cm×8.0 cm free latissimus dorsi myocutaneous flap which also facilitated the replacement of damaged Achilles tendon. The large area of wound in anterior tibia was covered with a medium-thickness skin graft. The 13.0 cm defect of left tibial bone was reconstructed by an in situ bone lengthening from the fractured left tibia in the stage Ⅱ surgery. At the 23-month postoperative follow-up, the flap survived well, with the Achilles tendon had regained a muscle strength at grade Ⅲ. Sensation was improved to S 4 in the weight-bearing areas of left foot, with TPD of 15 mm. The fracture of the extended tibial segment healed well. Overall function of the left ankle was rated as good using the American Orthopedic Foot and Ankle Society (AOFAS) standards.