Non-covalent functionalization of graphene nanoplate (NG) with surfactants developed for anti-inflammatory drug delivery applications

Abstract

The non-covalent functionalization of graphene nanoplate (GN) with Tween 80 (T80) and polyvinyl alcohol (PVA) was developed for anti-inflammatory drug delivery applications. This approach, based on the nonideal mixed micelle theory of surfactants, aims to enhance the surface properties of a carrier, potentially increasing surface area for improved drug loading and controlled release. This system exhibits a high drug loading efficiency (DLE) of 85 ± 2% and a significant drug loading content (DLC) of 28.33 ± 1.5%, making it highly efficient for drug encapsulation. The potential for controlled release, high thermal stability, and enhanced biocompatibility further emphasizes its suitability for anti-inflammatory drug delivery applications. FTIR and NMR spectroscopy confirmed hydrogen bonding interactions between GN-T80-PVA nanocomposite (GNTP). The Indomethacin (IDM) components, while TGA analysis revealed high thermal stability up to 350 °C. The morphology of functionalization of GN with T80 and polyvinyl alcohol (GNTP) nanoparticles was investigated using field emission scanning electron microscopy (FESEM), revealing a spherical shape with an average diameter of  ~ 50 nm. This study demonstrates that incorporating IDM and GN into a PVA/T80 matrix significantly influences nanoparticle size distribution during sonication-based preparation. The presence of IDM likely stabilizes the nanoparticles during their formation, which could lead to this change in size distribution. The change in particle size distribution suggests that the addition of IDM and GN could have a dual effect, leading to greater homogeneity. The drug solution in UV 200 to 800 nm of IDM exhibited a characteristic peak at 320 nm (λ_max). The EtOH solvent of GN showed no significant absorbance in the measured range. Upon formation of the IDM-GN complex, new absorbance bands appeared at 215, 238, and 321 nm, confirming successful drug loading onto the GN. Absolute zeta potential values >|30| mV are considered indicative of good colloidal stability. Combined TGA–DSC analysis of drug-loaded and unloaded nanocomposites (0–350°C) was completed. FESEM and powder X-ray diffraction (PXRD) data further substantiated successful IDM encapsulation, indicating an amorphous dispersion within the PVA/T80/GN nanocomposite with controlled aggregate size. Creating an amorphous solid dispersion is one way to improve bioavailability and increase the effectiveness of a drug. PXRD confirmed the monoclinic allotropic nature of the nanoparticles. A graph illustrating the release kinetics indicates that PVA-T80-GN nanocomposite successfully slows down IDM release, indicating that only about 40% of the IDM was released after 5 h and approximately 60% after 20 h. This shows a controlled-release mechanism. Creating an amorphous solid dispersion is one way to improve bioavailability and increase the effectiveness of a drug. Allotropy is a very important property for materials; these allotropic changes are the basis for heat treatment of many engineering materials. The crystallite size calculations in this study were performed using the most prominent peak observed at 26.6° 2θ in the XRD pattern of the GIT nanocomposite (PVA/T80/GN/IDM). This peak corresponds to the (002) plane of GN, which serves as the primary crystalline component in the system. The Scherrer equation (D = kλ/βcosθ) was applied to this peak after proper background subtraction using a polynomial fitting routine in the XRD analysis software. The calculated crystallite size of 11.47 Å represents the average dimension of ordered GN domains within the nanocomposite, as the drug (IDM) exists in an amorphous state as confirmed by the absence of characteristic crystalline drug peaks.