Sustained drug release and bactericidal activity of a novel, highly biocompatible and biodegradable polymer nanocomposite loaded with norfloxacin for potential use in antibacterial therapy

In this study, novel poly(3-hydroxybutyrate) (PHB) based Calcium–Iron Layered Double Hydroxide (Ca–Fe LDH) nanocomposites were investigated for sustained drug delivery application using the antibiotic norflaxacin (NFX) as a model drug. Compared with other LDH and montmorillonite nanoclays, Ca–Fe LDH showed a high drug loading capacity. In vitrodrug release experiments with PHB/NFX, PHB/NFX LDH, and PHB/PEG/NFX LDH were performed using two different phosphate buffer solutions of pH 5.3 and pH 7.4. Among these nanocomposites, the PHB/PEG/3 NFX LDH nanocomposite showed a very high drug release efficiency of 95.91% in pH 5.3 and 73.40 ± 3.41% in pH 7.4, which was followed by PHB/3 NFX LDH with a drug release efficiency of 82.60% in pH 5.3 and 66.81 ± 2.25% in pH 7.4. Furthermore, the drug release kinetics due to PHB/PEG/3 NFX LDH in pH 5.3 and pH 7.4 followed zero-order and Higuchi model kinetics, respectively. Characterization results of the polymer nanocomposite films using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission transmission electron microscopy (FETEM) and field emission scanning electron microscopy (FESEM) analysis as well as antibacterial activity of the PHB formulations against Staphylococcus aureusand Escherichia colirevealed excellent potential of the PHB based LDH nanocomposites for sustained drug release applications.