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

Here, we introduce a pioneering approach in the domain of transdermal drug delivery systems (TDDS) by using microneedles (MNs) fabricated from amorphous solid dispersion comprising only a model drug and an amphiphilic block copolymer to form a drug nanoformulation upon MN dissolution. This approach presents the most minimalistic approach to maximize drug loading in MN, reaching 40 wt.%. Using scanning electron microscopy, we carefully examined the morphology of MNs across a spectrum of drug loading ratios, revealing a remarkable consistency in structure and integrity. Mechanical testing confirms the MNs' proficiency in effective skin penetration. Furthermore, a comparative study on the formation of polymeric micelles underscores the innovative concept of a “nano-in-micro drug delivery system”, offering an approach to drug release. The results demonstrate that MNs manufactured from an amorphous solid dispersion of drug and amphiphilic block copolymer with ultra-high loading, enhancing the availability and release dynamics of hydrophobic drugs, positioning them as a potent tool for enhancing TDDS. This study sets a new benchmark in the utilization of polymer-drug nanoformulations for transdermal applications and underscores the exceptional capacity for high drug loading and the creation of adaptable drug delivery mechanisms for the studied amphiphilic block copolymer.