Optimization of preparation conditions for CTAB-modified Polygonatum sibiricum polysaccharide cubosomes using the response surface methodology and their effects on splenic lymphocytes

This study aimed to optimize the preparation conditions for cetyltrimethylammonium bromide-modified Polygonatum sibiricum polysaccharide cubosomes (CTAB-modified PSP-Cubs) by response surface methodology (RSM). Glyceryl-monooleate (GMO) was used as the lipid base for the cubosomes. The optimal preparation conditions of CTAB-modified PSP-Cubs were as follows: the mass percentage of PSP to GMO (X 1 ), Poloxamer 407 (F127) to GMO (X 2 ) and water to GMO (X 3 ) was 1.4%, 9% and 50%, respectively. The encapsulation efficiency (EE) of CTAB-modified PSP-Cubs under the experimental conditions was 62.4 ± 3.6%, which was close to our predicted value. The particle size, polydispersity index (PDI) and zeta potential of CTAB-modified PSP-Cubs were 427.7 ± 8.0  nm , 0.236 ± 0.024 and 19.2 ± 0.4 mV, respectively. Specific modifications were able to slow down in vitro release behaviors and reduce cytotoxicity to some extent. The effects of CTAB-modified PSP-Cubs on splenic lymphocytes were also investigated. When splenic lymphocytes were treated with CTAB-modified PSP-Cubs together with LPS or PHA , the results showed more favorable effects on cellular proliferation than blank cubosomes or free PSP at certain concentrations.