Alternative therapy of rheumatoid arthritis with a novel transdermal patch containing Siegesbeckiae Herba extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Siegesbeckiae Herba (SiH) is a traditional anti-rheumatic herbal medicine in China. A SiH derived product, Phynova Joint and Muscle Relief Tablets™, has been granted the UK license in 2015. Although transdermal delivery provides better patient compliance and relative constant plasma drug concentration, the feasibility of transdermal delivery of SiH was not clear. AIM OF THE STUDY: The aim of the present study was to develop a novel transdermal patch containing SiH extract for alternative therapy of rheumatoid arthritis. MATERIALS AND METHODS: SiH extract containing 48.5% (w/w) of kirenol was prepared from Siegesbeckia pubescens Makino. Then transdermal patches containing SiH extract were prepared by the solvent evaporation technique. The formulation of the transdermal patch was optimized based on the in vitro skin permeation experiment. Finally, the anti-inflammatory and analgesic activity of the optimal patch were evaluated by chronic inflammation model induced by complete Freund's adjuvant (CFA) and writhing model induced by acetic acid, separately. RESULTS: Oleic acid (OA) showed the maximum permeation enhancement effect with the enhancement ratio (ER) values of 3.32. Therefore, OA was used as a permeation enhancer in the transdermal patch. The optimal formulation consisted of SiH extract (10% of the matrix, w/w), OA (10% of the matrix, w/w), DURO-TAK® 87-2287 (pressure sensitive adhesive matrix) and Scotchpak™ 9701 (backing layer). The optimal transdermal patch containing SiH extract significantly reduced the degree of paw swelling and number of writhing in inflammation model and writhing model, respectively. CONCLUSIONS: The developed transdermal patch containing Siegesbeckiae Herba extract showed good anti-inflammatory and analgesic effects, which demonstrated a great potential for alternative therapy of rheumatoid arthritis.

Investigation of the permeation enhancer strategy on benzoylaconitine transdermal patch: the relationship between transdermal enhancement strength and physicochemical properties of permeation enhancer.

Permeation enhancer strategy is used to develop Benzoylaconitine (BA) of high molecular weight (603.7 Da) into transdermal patch. The present study was to achieve a patch with good analgesic and anti-inflammatory effects and investigate the relationship between physicochemical parameters of enhancers and enhancement strength. In vitro skin permeation study was used to evaluate the effect of enhancers, and correlation study was conducted to clarify the relationship between physicochemical parameters of enhancer and permeation amount. The enhancement molecular mechanism was characterized using FT-IR and molecular modeling. Finally, pharmacodynamic effect of BA patch was evaluated with analgesic and anti-inflammatory assessment. The correlation analysis indicated that the optimized patch containing permeation enhancer Plurol® Oleique CC497 with high surface tension (43.0 dyne/m), demonstrated the strongest skin permeation amount of 5.50 ±â€¯0.21 µg/cm2. According to the FT-IR and molecular modeling study, the enhancer with high surface tension demonstrated maximum interaction strength (Emix = -9.20 kcal/mol) with skin lipid and affected the skin protein region, which strongly disturbed skin lipid arrangement according to the results of ATR-FTIR study (wavenumber variation of νas CH2 of skin lipid > 2.00 cm-1) and molecular modeling (Cohesive Energy Density of skin lipid bilayer = 1.04E + 08 kcal/mol). It was indicated that only based on sufficient interaction strength and disturbing of both lipophilic and hydrophilic area of stratum corneum, permeation enhancer was able to demonstrated great permeation enhancement effect. Finally, BA transdermal patch was developed and showed excellent analgesic and anti-inflammatory effect, which was a potential preparation for the treatment of inflammatory pain.