PTX-loaded RSF nanospheres (Table 2). When the RSF concentration increased to 15 mg/ml, the diameter of PTX-loaded RSF nanospheres changed corresponding to the lower concentration
[RSF= 8 mg/ml]. It proves that the drug-loaded nanospheres range from 110~580 nm which apply to the intravenous chemotherapy is easy to be synthesized via varying the concentration of RSF solution and ethanol.
Table 2 Hydrodynamic diameter and polydispersity index of PTX-loaded RSF nanospheres prepared at different volume ratio of ethanol to RSF solution, [RSF]=15 mg/mL, [PTX]=3 wt%.
Considering the positive charge of DOX and negative charge of PTX-loaded RSF
nanospheres, …show more content…
Figure. 2 The UV spectra of free PTX (a) and DOX (b), showing the characteristic peaks of the drugs are overlapped at 235 nm.
To study the release of DOX and PTX in PTX-DOX-loaded RSF nanospheres respectively,
DOX-loaded RSF nanospheres, PTX-loaded RSF nanospheres and DOX-PTX-loaded RSF nanospheres incubated in buffered solution at pH 5.0 and pH 7.4 were investigated. The pH 5.0 is set up for simulating the acidic environment of tumor site where the pH is lower than that in normal tissues and organs. It was supposed to decrease the side-effect in the process of cancer treatment if the content of drug released under neutral condition lower than the acidic conditions.
The release of DOX from DOX-loaded RSF nanospheres were shown in Fig. 3a, b. The
DOX-loaded RSF nanospheres exhibited different release behaviors under different pH conditions.
In the first 24 h, the DOX-loaded RSF nanospheres both shown fast release at pH 7.4 and pH 5.0.
A sustained release was appeared in 7 days and the release rate of DOX under neutral condition was lower than that in acidic conditions as we had expected. It might be because the solubility …show more content…
The viability of Hela cells after treatment for a certain time were shown in Fig. 4 and HepG-2 cells were in Fig. 5. The in-vitro cellular growth inhibition of Hela and HepG-2 were both increased with the increasing of drug content and contact time.
The IC50 (half maximal inhibitory concentration) values of free DOX and PTX to Hela and
HepG-2 cells were listed in Table 3. DOX and PTX both exhibited time dependent toxicity, as the
IC50 values of DOX (DOX：IC50=0.75 μg/mL at 24 h; IC50=0.3 μg/mL at 48 h) and PTX (PTX：
IC50=8.0 μg/mL at 24 h; IC50=1.0 μg/mL at 48 h) decreased from 24 h to 48 h. The IC50 values of DOX to Hela and HepG-2 cells were higher than PTX at both 24 h and 48 h, which indicated the higher efficiency of DOX in inhibiting cancer cells.
To choose the suitable ratio is essential for drug efficiency. The inhibiting efficacy of dual drug-loaded RSF nanpspheres varied depending on the change of DOX/PTX ratio (Fig. 6a).