Photographs of the sample were taken at 1 h, 2 h, and 4 h. Other samples were studied in the same way. Based on the drug encapsulation efficiency, the same quantity of etoposide was applied to all formulations for the sedimentation
study. Determination of loading amount and in vitro release test The amount of incorporated etoposide was measured through UV–vis spectroscopy. A known weight of ECCNS sample was placed in a 10-mL flask, QNZ mw then 100 μL of 3 M HCl solution was subsequently added into it, and the flask was filled with 100% phosphate buffer solution (PBS) (pH = 7.4) until total volume reached 10 mL. After the ECCNS sample was totally dissolved, the concentration of etoposide was determined with a UV–vis spectrophotometer at 285 nm. The concentration of etoposide was calculated according to an already obtained calibrating curve Epoxomicin in vivo of etoposide (Abs = 0.00645c + 0.01599, r = 0.99923). The drug loading capacity and encapsulation efficiency are calculated as follows: The etoposide release test was performed in 180 mL PBS at pH 7.4,
5.8, and 3.0. ECCNS (25 mg) was resuspended in 10 mL PBS and loaded in a dialysis bag. The release system was swayed in a bath reciprocal shaker at 100 rpm and at constant temperature of 37°C above for 120 h. Aliquots (2 mL) were extracted at desired time intervals, and another 2 mL fresh PBS was added to the system. The accumulated amount of etoposide released was determined Silibinin by UV absorption at 285 nm. Cytotoxicity assay Cytotoxicity was characterized by MTT test through the human embryonic kidney (HEK) 293 T cells. 293 T cells with a density of 1 × 104 cells/well were seeded on a 96-well polystyrene plate, and each well contained 100 μL of DMEM (high glucose) medium supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin solution. Cells were subsequently
incubated at 37°C in a 5% CO2 humid incubator for 24 h. CCNSs, etoposide, and ECCNSs were added to the wells with concentrations 5, 10, 20, and 40 μg/mL in sequence. The HEK 293 T cells were incubated as described above for 24 and 48 h. A control experiment was performed with pure culture medium without treatment. Then, 20 μL (5 mg/mL) of MTT was added to each well, and the plate was further incubated for 4 h to deoxidize MTT under light-blocking condition. After removal of the MTT dye solution, cells were treated with 150 μL DMSO, and the absorbance at 490 nm was measured using ELX 800 UV reader (BioTek, Winooski, VT, USA), and cell viability was calculated by: Inhibition against SGC-7901 cells The antitumor ARN-509 research buy effect of CCNSs, etoposide, and ECCNSs against human gastric carcinoma (SGC-7901) cells was examined by cell viability test. SGC-7901 cells with a density of 8 × 104 cells/well were seeded on a 96-well polystyrene plate, and each well contained 100 μL of RPMI-1640 medium supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin solution.