Posaconazole-conjugated graphene microgel for fungal infection treatment: Development, optimization, and in vitro evaluation against Aspergillus niger

The present study aimed to develop and optimize posaconazole-conjugated graphene (PCZ-G) microgel for the treatment of cutaneous infections caused by fungus Aspergillus niger (A. niger). The Box–Behnken experimental design with three levels, three factors, and three center points was applied for optimization of PCZ-G microgel. Particle size (PS), polydispersity index (PDI), and entrapment efficiency were the three outputs utilized in the design matrix associated with Box–Behnken design (BBD), containing 17 runs. Three-dimensional response surface plots and contour plots have been generated using Stat Ease 360 software. On the optimized preparation, assessments were conducted on drug content, %CDR, PDI, PS, percentage entrapment efficiency (EE%), and in vitro antifungal activity. The optimized formulation of PCZ-G microgel showed a particle size of 1506 nm, an entrapment efficiency of 97.08±3.69%, a drug content of 94.43±1.09%, and other parameters all within the range of the model. In vitro release study showed prolonged drug release from the optimized formulation. Drugs and excipients were well integrated and physically stable in the designed microgel, which showed significant antifungal activity against A. niger.