In vitro nanodelivery of silibinin as an anticancer drug under pH response

Silibinin (SB) has gained much attention recently as a potential cancer preventive agent for its anti-carcinogenic and anti-proliferative properties. However, it has been shown to exhibit low bioavailability due to poor water dissolution. Therefore, a simple preparation method was developed with the aim to synthesize a controlled-release formulation of SB using carboxylated single-walled carbon nanotubes (COOH-SWCNT) as the nanocarrier. The loading of SB in the nanohybrid was estimated to be around 46 %. Both FTIR and Raman scattering studies confirmed that the conjugation process has taken place between SB and COOH-SWCNT. The release profiles demonstrated that the resulting nanohybrid possessed favorable sustained-release properties to be used in a controlled-release formulation, with satisfactory coefficients conformed well to the pseudo-second order release kinetic model. Furthermore, cell cytotoxicity assays of SB-loaded nanohybrid in normal cell lines (3T3 and MRC-5) and cancer cell lines (HepG2 and A549) were also investigated. Preliminary in-vitro cell toxicity studies suggest that the SB-loaded nanohybrid is not acutely toxic while significantly inhibiting the growth of cancer cells in comparison with free SB. The findings from this work indicate that COOH-SWCNT may be a potential drug delivery nanocarrier when non-covalently loaded with SB.