Polysaccharides of Atractylodes macrocephala Koidz-loaded nanostructured lipid carriers: Optimization on conditions by RSM and immunological activity in vitro

The main purpose of this study was the preparation, optimization, characterization, and in vitro immunological activity evaluation of the polysaccharides of Atractylodes macrocephala Koidz-loaded nanostructured lipid carriers (PAMK-NLC). Both the blank NLC and PAMK-NLC were prepared using melt-emulsification and ultra-sonication techniques. The optimization of preparation conditions were a stearic acid to caprylic/capric triglyceride mass ratio of 2:1, a poloxamer 188 to soybean lecithin mass ratio of 2:1, and an ultrasound time of 12 min; these parameters were identified using response surface methodology (RSM). Under these conditions, the encapsulation efficiency was around 76.85% and the polydispersity index was around 0.281, indicating a good dimensional distribution. Furthermore, the potential of PAMK-NLC to enhance immunological activity in vitro was investigated in murine splenic lymphocytes. The results showed that PAMK-NLC could significantly stimulate lymphocyte proliferation and increase the ratio of CD4 + to CD8 + T cells. In conclusion, these findings indicated that PAMK-NLC possessed an efficient immunological activity, and that NLC is suitable for the delivery and protection of PAMK in clinical use.