Enhanced Transdermal Delivery of Rhein In Vitro Using a Dissolving Microneedle Patch
Authors:   Division of Pharmacy and Technology, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand, Saepang Kamchai ,   Research Group in Herbal and Development of Formulation and Delivery Systems for Elderly Adults and Cancer Treatment, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand, Imon Nithi ,   Division of Pharmacy and Technology, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand, Plangsorn Sorasak ,   Division of Pharmacy and Technology, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand, Khuanrupsuan Tiyada ,   Division of Pharmacy and Technology, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand, Buranrat Benjaporn ,   Research Group in Herbal and Development of Formulation and Delivery Systems for Elderly Adults and Cancer Treatment, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand,   Faculty of Medicine, Mahasarakham University, Maha Sarakham 44000, Thailand, Pitaksuteepong Tasana ,   Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand, Boontha Supavadee ,   Division of Pharmacy and Technology, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand,   Research Group in Herbal and Development of Formulation and Delivery Systems for Elderly Adults and Cancer Treatment, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
Published: August 2024

Transdermal delivery presents an attractive option for rhein (RN) to circumvent the undesirable laxative effect associated with oral administration. However, the stratum corneum (SC) acts primarily as a barrier against RN permeation across the skin. Thus, dissolving microneedle patches (DMNPs) serve as an effective tool for enhancing skin permeation by bypassing the SC. This study focused on preparing a RN-loaded DMNP and evaluating its efficacy in enhancing transdermal RN delivery. The DMNP was fabricated from a 10% (w/w) aqueous polyvinyl alcohol solution using the micro-molding technique. The efficiency of the prepared DMNP in delivering RN across neonatal porcine skin was compared in vitro with a film as a control. The DMNP effectively pierced a skin-simulating Parafilm® M stack and neonatal porcine skin. The DMNP completely dissolved within 30 min after skin insertion. A 1 cm × 1 cm piece of the DMNP contained 96.5 ± 2.0 μg of RN. In a light-protected drug release study, the DMNP released 79.44 ± 2.0% of RN within 8 h and then achieved approximately 100% of RN release at 24 h. The in vitro permeation study showed that the DMNP exhibited a significantly greater RN permeation than the film. The amount of RN permeated at 24 h from the DMNP was 31.6 ± 2.4 μg/cm2, corresponding to a flux of 1.24 ± 0.10 μg/cm2/h, whereas RN permeation from the film was undetectable. Therefore, the DMNP exhibits promising potential for enhancing transdermal RN delivery in vitro and could be used in further in vivo studies.