Genesys 6 uv vis

The release profile of vitamin C and hydrocortisone from the samples was evaluated using a flow-through procedure in a closed-loop system (USP4 Sotax drug release apparatus, Donau Lab, Dietikon, Switzerland). The samples weighing 120 ± 2 mg were inserted into USP4 flow-through cells. The 50 mL of PBS was used as an elution medium, which perfused at a rate of 3 mL per min at 37 °C. At predetermined time points, 1.5 mL samples were collected for the evaluation of vitamin C and hydrocortisone concentration and replaced with an equal amount of fresh PBS. The amount of vitamin C in collected samples was evaluated by measurement of absorbance at 252 nm using a UV-spectrophotometer (Genesys 6 UV-Vis, Thermo Fisher Scientific, Waltham, MA, USA). Concentrations of vitamin C in collected samples were determined using the absorbance values obtained with the calibration curve that was prepared applying known concentrations of vitamin C. Hydrocortisone concentrations were evaluated using ELISA kit. The vitamin C and hydrocortisone release profiles from the samples were expressed as cumulative concentration at predetermined time intervals

The release profile of vitamin C from the CHN/A + vit C sample (weighing 250 mg) was examined using a flow-through procedure in a closed-loop system. The experiment was carried out in the USP4 Sotax drug release apparatus (Donau Lab, Switzerland) using 50 mL of PBS as an elution medium, which circulated at a rate of 3 mL per min at 37 °C. At specified time intervals, 0.5 mL samples were collected for the evaluation of vitamin C concentration. In order to maintain the original volume of the elution medium, the system was refilled with the same capacity of the fresh PBS. Vitamin C concentrations were determined by measurement of absorbance values at a wavelength of 252 nm using a UV-spectrophotometer (Genesys 6 UV-Vis, Thermo Fisher Scientific, Waltham, MA, USA). A calibration curve was prepared for known concentrations of vitamin C solutions, which were prepared in PBS in the range of 3.75–60 μg/mL. The vitamin C release profile from the CHN/A + vit C biomaterial was presented as cumulative concentration at defined time intervals.

To estimate the amount of vitamin C released from the structure of the biomaterials, a flow-through test in a closed-loop system was used. For this purpose, CHN/A +100 and CHN/A + 200 samples weighting 250 ± 2 mg were applied. The experiment was conducted in a drug release apparatus (USP4 Sotax, Donau Lab, Budapest, Hungary) with the elution medium (PBS) in the final volume of 50 mL. The circulated rate was 3 mL per min at 37 °C. Vitamin C concentration was evaluated in 0.5 mL samples collected at defined time intervals. The amount of the elution medium was refilled to the original volume with freshly prepared PBS after sample collection. UV-spectrophotometer with 252 nm wavelength (Genesys 6 UV-Vis, Thermo Fisher Scientific, Waltham, MA, USA) was used to determine the cumulative concentration of vitamin C. The absorbance values were measured and concentration was calculated using the calibration curve prepared for 3-O-ethyl-L-ascorbic acid solution (3.75–60 µg/mL).