ABSTRACT
@#Polyethylene glycol (PEG) of different lengths were prepared to investigate their effects on oral absorption of nanostructured lipid carrier (NLCs).Three kinds of PEG-modified NLCs with different chain lengths, including polyethylene glycol (100) monostearate (S100), polyethylene glycol (55) monostearate (S55), polyethylene glycol (40) monostearate (S40), were prepared by film dispersion method.Coumarin 6 was chosen as a fluorescent probe to characterize the physicochemical properties of NLCs with different lengths.Meanwhile, the stability of NLCs in simulate buffer, the release behavior, cytotoxicity of NLCs, the uptake kinetics and cellular uptake mechanisms were evaluated. This work demonstrated that the thickness of the hydrated layer increased with the increase of PEG length. Of note, S100-modified NLCs (pNLC-EG100) exhibited higher cellular uptake efficiency compared with other formulations. Thus, S100 was optimized as the best molecular weight for PEG-modified NLCs on oral drug delivery system.
ABSTRACT
@#To construct nanostructured lipid carriers(NLCs)with different particle sizes but the same other physicochemical properties, central composite design was adopted. Coumarin-6(C-6)was selected as the model drug due to its high lipophilicity and high fluorescence intensity. Physicochemical properties of NLCs with 100 nm, 200 nm and 300 nm in particle size could remain stable during certain time in K-R solution and PBS. Release experiments in vitro showed that cumulative release of C-6 in NLCs was less than 7% after 24 h. The MTT assay indicated that both blank NLCs and C-6 loaded NLCs showed low toxicity. To confirm the integrity of NLCs in gastrointestinal tract, DiR-loaded NLCs were prepared and the distribution in vivo was monitored by fluorescence imaging. After 6 h oral administration, intact DiR-loaded NLCs could stiu be found, suggesting that NLCs could be used to characterize the uptake in gastrointestinal tract.