Quantifying Release of Steroidal Derivatives

UV-Visible (UV–Vis-NIR UV 3600-spectrometer Shimadzu Company, Kyoto, Japan) absorbance was considered as an indicator of the release of steroidal oxazoline and aziridine derivatives from electrospun mats. The dehydrated, electrospun, extract-loaded-nanofibrous mats were first divided into 12 × 12 cm² squares and the extracted compound was estimated as a function of the weight mat. The drug loading into CH-PVP nanofibres was 12 mmole/100 gm CH-PVP from each sample, i.e., A, B, C, and D. The specimens were placed in individual vessels containing 50 mL buffer saline phosphate (pH = 7.40), and the vessels were incubated at 310 K. Release experiments were performed by dispersing 200 mg of the ST-CH nanofibers in 50 mL of the buffer solution. After a certain time, 5 mL of the buffer was replaced with the same volume of fresh buffer to maintain a constant volume. A mixture of 3 mL methanol and 2 mL distilled water was prepared and added to each buffer to determine the absorbance by UV-Visible spectroscopy at 300 nm. A standard calibration curve was applied to measure the concentration of the free steroidal oxazoline and aziridine derivatives. The percentage of the released steroidal oxazoline and aziridine derivatives was then calculated based on the initial weight of these compounds incorporated in the electrospun nanofiber mats. The results were plotted over time, up to 60 h.