A thermoplastic elastomer patch matrix for traditional Chinese medicine: design and evaluation

Abstract

Objective: To design and evaluate a novel pressure sensitive adhesive (PSA) patch containing traditional Chinese medicine (TCM) using styrene–isoprene–styrene (SIS) copolymer.

Method: A mixture D-optimal design with ternary response surface diagram was employed in the optimization process. The proportions of SIS copolymer, tackifying resin and plasticizer were selected as the independent variables while tack force, peel strength of the patch and skin penetrability of methyl salicylate were selected as the dependent variables. The optimized patch was then evaluated including in vivo absorption, pharmacological activities and skin irritation, by comparing with a commercial patch based on natural rubber.

Results: The optimized patch, which comprised 30.0% SIS copolymer, 26.6% tackifying resin and 43.4% plasticizer, was superior to commercial patch in skin permeation, pharmacological activities and skin biocompatibility.

Conclusion: SIS copolymer was a suitable substitute to natural rubber in producing patches containing TCM formula.

• Capsaicin
• formulation optimization
• methyl salicylate
• skin permeation
• thermoplastic elastomer
• traditional Chinese medicine