Phthalate angico gum nanoparticles-based microneedles: a long-acting transdermal delivery system for antiretroviral therapy

Microneedles (MN) have gained attention as an alternative transdermal drug delivery system (TDDS) due to their ease of administration and painlessness, and the possibility of incorporating free drugs or nanoparticles to modulate drug release. This study aimed to develop TDDS for the antiretroviral drug nevirapine (NVP), using MN-containing phthalate angico gum (PAG) nanoparticles (NP). NVP-loaded NP were prepared as nanosuspensions (NPns) or lyophilized nanoparticles (NPfd) and incorporated into chitosan (CS) and polyvinylpyrrolidone (PVP) hydrogels to produce MN (M-NPns and M-NPfd). The MN were fabricated using a micro-molding method with a siloxane mold. The selected M-NPns and M-NPfd were characterized by scanning electron microscopy (SEM), permeation assays using Franz diffusion cells with porcine ear skin, and histological studies using MN containing 0.1 % rhodamine. Both M-NPns and M-NPfd showed significant drug permeation after 72 h, and histological assays demonstrated that MN promoted skin micropiercing. The incorporation of NP into CS: PVP-MN resulted in suitable mechanical properties and slow, progressive release of NVP. This study highlights the potential of MN containing PAG NP as an innovative long-acting TDDS for NVP delivery, by combining the technology of MN and NP, which may improve patient adherence and reduce the frequency of administration.