Novel strategy for immunomodulation: Dissolving microneedle array encapsulating thymopentin fabricated by modified two‐step molding technology

Graphical abstract Figure. No Caption available. HighlightsTP5‐DMNA was developed using a two‐step molding technology for immunomodulation.BSA was used as co‐material to fabricate TP5‐DMNA for higher mechanical strength.The TP5‐DMNA had equivalent immunomodulation efficiency to intravenous injection.The TP5‐DMNA can be self‐administrated with minimal pain and good compliance. Abstract Thymopentin (TP5) is commonly used in the treatment for autoimmune diseases, with a short plasma half‐life (30 s) and a long treatment period (7 days to 6 months). It is usually administrated by syringe injection, resulting in compromised patient compliance. Dissolving microneedle array (DMNA) offers a superior approach for transdermal delivery of biological macromolecules, as it allows painless penetration through the stratum corneum and generates minimal biohazardous waste after dissolving in the skin. Despite recent advances in DMNA as a novel approach for transdermal drug delivery, problem of insufficient mechanical strength remains to be solved. In this study, TP5‐loaded DMNA (TP5‐DMNA) was uniquely developed using a modified two‐step molding technology. The higher mechanical strength was furnished by employing bovine serum albumin (BSA) as a co‐material to fabricate the needles. The obtained TP5‐DMNA containing BSA displayed better skin penetration and higher drug loading efficiency than that without BSA. The in vivo pharmacodynamics study demonstrated that TP5‐DMNA had comparative effect on immunomodulation to intravenous injection of TP5, in terms of ameliorating the CD4+/CD8+ ratio, SOD activity and MDA value to the basal level. Only mild irritation was observed at the site of administration. These results suggest that the novel TP5‐DMNA utilizing BSA provides an alternative approach for convenient and safe transdermal delivery of TP5, which is a promising administration strategy for future clinical application.