Synthesis of Chitosan/Polyvinylpyrrolidone functionalized Single-Walled Carbon Nanotubes as a Novel pH-Sensitive Nanocarrier for Levofloxacin Drug Delivery: In-Vitro Release Properties and Release Kinetics

In the present study, a novel pH-sensitive nanocarrier was prepared by grafting chitosan/polyvinylpyrrolidone (CS/PVP) on the surface of single-walled carbon nanotubes (SWCNTs). Levofloxacin (LVX), an anti-bacterial model drug, was loaded onto the resulting nanocomposite. The as-prepared nanocomposite was characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) techniques. The adsorption procedure was investigated under different sorption conditions, such as solution pH, adsorbent dosage, initial drug concentration, contact time, and temperature. The experimental data were analyzed using both non-linear and linear forms of kinetic and isotherm models. Based on the sum of squares errors and coefficient of determination values, the non-linear forms of the pseudo-2nd-order kinetic model and Langmuir isotherm model provided the best fit to the experimental data. Adsorption thermodynamic showed an exothermic and spontaneous nature of the drug sorption on the surface of the nanoadsorbent. In-vitro drug release tests were studied in simulated gastric fluid (SGF; pH = 1.2) and intestinal fluid (SIF; pH = 7.4) at 37 °C. The pH-sensitive nanocarrier indicated sustained drug release over 36 h. Nearly 99.76% of the drug was released in simulated intestinal fluid at pH = 7.4 in 36 h and 22.72% was released in simulated gastric fluid at pH = 1.2 in 30 min. The drug release profiles were well-fitted by the Korsmeyer-Peppas kinetic model, and the release mechanism of the nanocarrier was related to non-Fickian transport. Furthermore, the antimicrobial efficacy of the fabricated nanomaterials was evaluated against Staphylococcus aureus (Gram-positive). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the nanoparticles were subsequently quantified.