Abstract:
OBJECTIVE To modernize the traditional preparations in medical institutions, Baicaoshanggao(BCSG), into a contemporary gel paste formulation, and to assess its formulation process, in vitro release, transdermal penetration, safety, and anti-osteoarthritic effects.
METHODS Baicaoshanggao plaster(BCTG) was developed using low-temperature cross-linking and high-speed mixing technology. The BCTG formulation was optimized through single-factor investigation and Box-Behnken response surface design, focusing on appearance, excipient, initial adhesion, adhesion holding force, peel strength, and overall adhesion as evaluation criteria. The in vitro release and transdermal penetration of BCTG were examined using the paddle over disk method and Franz diffusion cell method, respectively, with eugenol, trans anethole, borneol, total aconitine(aconitine, hypaconitine, mesaconitine), camphor, and Ethyl 4-methoxycinnamate as marker compounds. The safety and anti-osteoarthritic efficacy of BCTG were evaluated in rat osteoarthritis model established using the modified Hulth technique.
RESULTS The study successfully formulated BCTG, with the optimal matrix composition being 23.642 g glycerol, 6.314 g NP-700, 45 mg dihydroxyaluminium aminoacetate, 0.933 g alcohol extract, 3 mL ethanol, 27.946 g water, 1.8 mg EDTA-2Na, 33 mg tartaric acid, and 1.166 g aqueous extract. The cumulative release of the index components from BCTG reached 55.34, 18.04, 158.52, 455.64, 2185.44, and 2.73 μg·cm−2, respectively, with corresponding cumulative permeation amounts of 37.47, 12.27, 111.75, 317.86, 1131.82, and 2.07 μg·cm−2 over 22 h. BCTG exhibited reduced skin irritation and enhanced biocompatibility and safety compared to BCSG. Behavioral assessments, inflammatory factor expression, and HE staining confirmed the potent anti-osteoarthritic effects of BCTG, comparable to BCSG.
CONCLUSION BCTG demonstrates favorable in vitro transdermal permeability and anti-osteoarthritic properties, ensuring safety and reliability for topical application. This research provides insights into the transformation and development of traditional plasters into modern gel plaster formulations.