Dissolving Microneedle Systems for the Oral Mucosal Delivery of Triamcinolone Acetonide to Treat Aphthous Stomatitis

A microneedle (MN) oral mucosal patch system was prepared to increase its adhesive strength, to improve the delivery of triamcinolone acetonide (TA) into the mucosa, and to protect the adhesive layer from mouth movement and saliva. The MN oral mucosal patch system consists of an adhesive layer containing TA and a backing layer. The adhesive layer consists of a base with a thickness of 50 μm, 300 μm long MNs, and 18% TA. After patches were attached to the tape-stripped porcine skin for a predetermined period of time, the adhesion of the patches was observed. TA was extracted from the skin, and the amount of TA was measured using high-performance chromatography. When the adhesive layer was applied for 10 s, the adhesive strength was 1.69 N mm/cm ² with microneedles and 0.41 N mm/cm ² without microneedles. An oral mucosal patch with MNs (TA MN-AL) delivered 42% more TA into the skin than an oral mucosal patch without MNs (TA AL). Also, as attachment time increased, the amount of TA delivered was significantly greater using a TA MN-AL compared to a TA AL. The addition of MNs can increase the adhesion of the oral mucosal patch to the mucosa and thus improve the efficiency of drug delivery.