Silymarin loaded solid lipid nanoparticles for oral delivery: Development, characterization and cytotoxic effect on breast cancer cells

Abstract

The current study aimed to develop a silymarin (SM) loaded solid lipid nanoparticles (SLNs). Further, silymarin loaded solid lipid nanoparticles (SM-SLNs) were characterized for different quality parameters. The SLNs were prepared by temperature modulated solidification technique. The glyceryl monostearate (GMS) was selected as lipid, tween 80 as surfactant and mannitol as cryoprotectant. The SM-SLNs were characterized for particle size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE), thermal behavior, and crystallinity. Further, the formulation was elucidated by MTT assay for cytotoxicity assessment. The particle size and PDI of the optimized formulation was found to be 178.6 ± 4.32 nm and 0.146, respectively. ZP (-36.4 mV) with a negative surface charge confirmed the physical stability of SLNs. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) confirmed the transformation of lipid into SLNs through polymorphic transition of lipid crystallinity from β'-modification to α-modification and conversion of crystallinity of drug to amorphous state. The optimized formulation had an EE of 79.86%. The in-vitro drug release depicted a burst release for 1 h followed by fast release for 6 h and then sustained release over a duration of 24 h. SM-SLNs significantly reduced the growth of MCF-7 cells compared to silymarin. SM-SLNs exhibited small size in nanometer with narrow distribution, physically stable, and high entrapment efficiency. The developed nanoformulation could be used as a suitable drug delivery system for silymarin that has low water solubility, and a promising candidate for development of effective formulation in cancer therapy.