Transdermal drug delivery of triptolide-loaded nanostructured lipid carriers: Preparation, pharmacokinetic, and evaluation for rheumatoid arthritis.

The objective of this present study was to develop and evaluate the triptolide-loaded nanostructured lipid carriers (TPL-NLCs) for transdermal drug delivery system (TDDS). TPL-NLCs was prepared with emulsification technique and optimized by central composite design of a response surface methodology (CCD-RSM). The optimized TPL-NLCs were spherical and physically stable with the average size of 139.6.0 ± 2.53 nm and Zeta potential of -36.03 ± 2.41 mV. The encapsulation efficiency and drug loading were 97.15% ± 9.46 and 10.35% ± 1.12, respectively. Moreover, the in vitro release study showed that TPL-NLCs had a sustained release profiles and the in vitro penetration study indicated that TPL-NLCs could effectively penetrate into skin. Besides, the methodology of skin-blood synchronous microdialysis was established to evaluate the pharmacokinetics of TPL-NLCs in vivo and the results displayed that the TPL concentration in skin was higher than that in blood. And TPL-NLCs presented a remarkable effect of decreasing knee edema, inhibiting inflammation by regulating the levels of TNF-α, IL-1β and IL-6, which indicated that TPL-NLCs was a promising topical administration in treatment of edema and inflammation associated with rheumatoid arthritis (RA).