Preparation, characterization, and in vivo study of rhein solid lipid nanoparticles for oral delivery

In this study, rhein-SLNs were successfully produced by hot homogenization followed by ultrasonication. Precirol ATO5 in which rhein exhibited higher partition coefficient was selected for preparation of SLNs. In the dynamic light scattering, the rhein-SLNs showed a smaller size with a mean value of 120.8 ± 7.9 nm and with zeta potential of -16.9 ± 2.3 mV. SLNs exhibited a good stability during the period of 2 months. The SLNs indicated faster drug release with a burst release within 2 hr and followed by a sustained release with a biphasic drug-release pattern. Comparing with the same concentration (free drug), the cellular cytotoxicity of rhein-loaded SLNs increased significantly at the same incubation condition. In vivo, the AUC_0-t of rhein in the form of SLNs was significantly increased and was 2.06-fold that of suspensions group. The results showed an increased oral absorption and improved the oral bioavailability of rhein by the formulation of SLNs.