2.6. In Vitro Release Test of Docetaxel

In vitro release profile of docetaxel from NPs was evaluated according to the reported method with slight modification [30]. An aliquot (0.2 mL) of docetaxel-loaded NPs (2%, w/v) dispersion was placed in a dialysis tube (MWCO: 6–8 kDa, Gene Bio-Application Ltd., Yavne, Israel) and transferred to 20 mL of phosphate buffer saline (PBS, pH 6.0 and 7.4) as a release medium, which is maintained at 37.0 ± 0.5 °C with a stirring rate of 100 rpm. An aliquot of the release media (0.2 mL) was sampled at predetermined time intervals (0, 1, 2, 4, 6, 8, 12, 24, 36, and 48 h) and replaced with the equal volume of fresh medium. Docetaxel in aliquots was quantitatively analyzed by the HPLC system described above. The released amount (%) of drug was calculated by the following formula.

where C_t, V_R, and V_s indicate drug concentration in the release medium at the corresponding time point, volume of release medium, and sampling volume, respectively.