Microneedle System Coated with Hydrogels Containing Protoporphyrin IX for Potential Application in Pharmaceutical Technology.

The article aims to outline the potential of treating malignant skin cancer with microneedles covered with polymer layers containing a photosensitizer-protoporphyrin IX disodium salt (PPIX). The usefulness of stereolithography (SLA), which is a form of 3D-printing technology, for the preparation of a microneedle system with protoporphyrin IX was demonstrated. The SLA method allowed for pyramid-shaped microneedles to be printed that were covered with three different 0.1% PPIX hydrogels based on sodium alginate, xanthan, and poloxamer. Rheological tests and microscopic analysis of the hydrogels were performed. Microneedles coated with two layers of poloxamer-based hydrogel containing 0.1% PPIX were subjected to release tests in Franz diffusion cells. The release profile of PPIX initially increased and then remained relatively constant. The amount of substance released after a four-hour test in three Franz cells was 0.2569 ± 0.0683 mg/cm². Moreover, the acute toxicity of this type of microneedle was assessed using the Microtox system. The obtained results show the usefulness of further development studies on microneedles as carriers of photosensitizing agents.