Title:Optimization of the Transdermal Delivery System in Astilbin Microemulsion
with Improved Stability and Anti-psoriatic Activity
Volume: 20
Issue: 3
Author(s): Yutong Ding, Lijuan Liu, Yayun Wu, Yang Wang*Ruizhi Zhao*
Affiliation:
- School of Pharmacy, Tianjin University of Traditional Chinese Medicine,
Tianjin, China
- The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Neihuan Xilu, Guangzhou Higher Education
Mega Center, Guangzhou, 510006, China
- Guangdong Provincial Key Laboratory of Clinical Research on Traditional Chinese Medicine,
Syndrome, Neihuan Xilu, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
Keywords:
Astilbin, microemulsion, gallic acid, psoriasis, stability, TEM.
Abstract:
Background: Astilbin is a promising candidate drug for psoriasis. However, the poor solubility
and stability limited its clinical application.
Purpose: The present work aimed to develop a stable microemulsion of astilbin formulation and evaluate
its effect in vitro and in vivo.
Methods: Oil phase, surfactants, and cosurfactants were screened using solubility and stability of astilbin
as the index. The central composite experiment design and response surface methodology analysis
were adopted to optimize microemulsion parameters. The particle size, zeta potential, polydispersity
index, viscosity, drug content, encapsulation, transmission electron microscopy (TEM), and stability of
the optimized microemulsion were evaluated. Then, the drug release and anti-psoriasis effects were
evaluated in a mouse model induced by imiquimod.
Results: The optimum formulation contained Labrafil M 1944 Cs (10.12%), Polyoxyethylene Castor
Oil 35 (37.41%), propylene glycol (12.47%), water (40%), and gallic acid (2.9%), and the average particle
size was 14.71 nm. The permeability of astilbin from the optimized astilbin-gallic acid microemulsion
in 24 hr was 4.39 times higher compared with the astilbin’s microemulsion. The content of astilbin
in astilbin-gallic acid microemulsion remained unchanged after being stored at 25°C for 4 months compared
with astilbin aqueous (3 h) and astilbin microemulsion (185 h). Compared with the model group,
the optimized formulation decreased the PASI score and Baker score by 49% and 73%, respectively,
which showed a favorable anti-psoriasis effect. Moreover, there was no difference in the anti-psoriasis
effect between the optimized group and the positive control.
Conclusion: These results indicated that the astilbin-gallic acid microemulsion might be a potential
topical drug used for the treatment of psoriasis.
