Pullulan microneedle patches for the efficient transdermal administration of insulin envisioning diabetes treatment

• Main Author: Fonseca, Daniela F. S.
• Publication Date: 2020
• Other Authors: Costa, Paulo C., Almeida, Isabel F., Dias-Pereira, Patrícia, Correia-Sá, Inês, Bastos, Verónica, Oliveira, Helena, Duarte-Araújo, Margarida, Morato, Manuela, Vilela, Carla, Silvestre, Armando J. D., Freire, Carmen S. R.
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10773/37708
• topic: Pullulan; Polysaccharides; Insulin; Microneedles; Transdermal drug delivery

The present study reports the fabrication of dissolvable microneedle (MN) patches using pullulan (PL), a water-soluble polysaccharide with excellent film-forming ability, for the transdermal administration of insulin, envisioning the non-invasive treatment of diabetes. PL MNs patches were successfully prepared by micromoulding and revealed good thermal stability (Tdmax = 294 °C) and mechanical properties (>0.15 N needle-1), penetrating skin up to 381 μm depth, as revealed by in vitro skin tests. After application into human abdominal skin in vitro, the MNs dissolved within 2 h releasing up to 87% of insulin. When stored at 4, 20 and 40 °C for 4 weeks, insulin was able to retain its secondary structure, as shown by circular dichroism spectropolarimetry. The prepared PL MNs were non-cytotoxic towards human keratinocytes, being suitable for skin application. These findings suggest that PL MNs have potential to deliver insulin transdermally, thus avoiding its subcutaneous administration.