Kinetics and in vitro Release Studies of Drug Loaded Silver Nanoparticles from Indigofera tinctoria Extract

Silver nanoparticles (AgNP’s) have been successfully fabricated via bio-reduction of Indigofera tinctoria plant extract as the reducing and capping agent. The effects of pH and temperature on the formation of the AgNP’s have been studied. The synthesized AgNP’s have been characterized using UV-Visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Zeta potential analysis, Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Antimicrobial activities of the synthesized AgNP’s have been tested against both bacterial and fungal strains by agar well diffusion method. The biomass-capped AgNP’s imparted antimicrobial activity by inhibiting the growth of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Aspergillus niger and Penicillium chrysogenum. The antioxidant activities of the synthesized AgNP’s exhibit low IC50 value of ~55.72 μg/mL. Studies on drug loading and kinetics of drug release reveal that I. tinctoria AgNP’s follow the zero-order kinetics at pH 4.6 and pH 7.4. The gradient value of 0.568 (pH 4.6) and 0.6 (pH 7.4) falls between 0.42 < n < 0.85 when fitted into Peppa’s plot indicating that the drug release follow an anomalous transport or non-Fickian diffusion transport, indicating that the diffusion is time dependent.