Self-Nanoformulating Poly(2-oxazoline) and Poly(2-oxazine) Copolymers Based Amorphous Solid Dispersions as Microneedle Patch: A Formulation Study

A pioneering approach in the domain of transdermal drug delivery systems (TDDS) is introduced by using microneedles (MNs) fabricated from an amorphous solid dispersion comprising only a model drug and an amphiphilic block copolymer to form a drug nanoformulation upon MN dissolution. To maximize drug loading and ensure consistent release, a minimalist formulation that achieves 40 wt% drug loading, which is a significant improvement over existing methods, is developed. Using scanning electron microscopy, the morphology of MNs is examined across a spectrum of drug loading ratios, demonstrating the consistency in structure and integrity. Mechanical testing confirms the MNs' proficiency in effective skin penetration. A comparative study on the formation of polymeric micelles underscores the innovative concept of a “nano-in-micro drug delivery system”. The results demonstrate that MNs manufactured from an amorphous solid dispersion of drug and amphiphilic block copolymer with ultra-high loading enhance the availability and release dynamics of hydrophobic drugs, positioning them as a tool for enhancing TDDS. This study sets a new benchmark in the utilization of polymer-drug nanoformulations for transdermal applications and underscores the capacity for high drug loading and the creation of adaptable drug delivery mechanisms for the studied amphiphilic block copolymer.