Novel Bletilla striata polysaccharide microneedles: Fabrication, characterization, and in vitro transcutaneous drug delivery

Dissolving microneedles (MNs) have been widely studied for their applications in effective transdermal drug delivery due to their ability to dissolve within the skin. This study details the first reported successful preparation of novel dissolving MNs using Bletilla striata polysaccharide (BSP), a natural glucomannan material, and investigates the potential for using such MNs as a transdermal drug delivery vector. The prepared dissolving Bletilla striata polysaccharide microneedles (BMNs) had excellent moldability and were easily detached from the mold. Texture analysis and histological examination confirmed BMNs were strong enough to insert into the skin. The skin appeared slight irritation after removal of BMNs, but recovered within 24 h. Confocal laser scanning microscopy (CLSM) studies indicated that rhodamine B (RB) loaded in BMNs (as a model drug) could be gradually released, along with the dissolution of BSP in vivo, and then diffused from the insertion site to the periphery. Furthermore, we found that the RB-loaded BMNs could provide sustained drug release via the in vitro Franz cell experiment. These findings demonstrate that novel dissolving BMNs can be easily-manufactured, loaded with drug, and inserted into the skin for drug delivery.