Synthesis, characterization and biological influences of rifaximin loaded melanin/zinc oxide nanoparticles

Abstract

The present study aims to design a pH-sensitive and effective nano-drug carrier with potent antimicrobial efficiency. The drug rifaximin is known to exhibit antimicrobial properties against many microbes. But due to some native properties such as permeability and poor solubility, this drug exhibits very less antimicrobial activity against intracellular pathogens. Therefore, rifaximin-loaded melanin/ZnO nanoparticle (Rif@ML/Zn-NPs) was synthesized for targeted release at the bacterial infection site and biological importance was systemically examined. FTIR, SEM, XRD, Zeta potential and TGA demonstrated that the Rif@ML/Zn-NPs were synthesized by interaction between the rifaximin and ML/Zn-NPs. Rif@ML/Zn-NPs possess outstanding antibacterial capabilities against various gram-positive (S.aureus, B thuringiensis) and gram-negative bacteria (E.coli). The highest antibacterial activity was recorded against B. thuringiensis with zone of inhibition of 35 mm while the respective zones of inhibitions for E. coli and S. aureus were recorded as 32 mm and 34 mm respectively. Cytotoxicity of Rif@ML/Zn-NPs was analyzed and the results revealed that Rif@ML/Zn-NPs did not exhibit any toxicity. Antioxidant activity of Rif@ML/Zn-NPs was also investigated and it was found that it is a better antioxidant as compared to original rifaximin. Rif@ML/Zn-NPs exhibited excellent sustained release of rifaximin (95%) at pH 7.2. Kinetic data of drug release study obeyed Higuchi kinetic model. The current study proves to be a cost-effective and environment-friendly approach for the synthesis of Rif@ML/Zn-NPs for drug delivery system.