Physicochemical Properties of Pineapple Stem Fiber/Gellan Gum Biocomposite Films as a Potential Platform for Buccal Drug Delivery.

The physicochemical properties of buccal films are vital for evaluating their suitability for mucosal applications. By focusing on these properties, researchers can enhance the mechanical functionality and mucoadhesion of the films. This study aimed to overcome the mechanical limitations of neat gellan gum and to produce biocomposite films with enhanced physicochemical properties and mucoadhesive properties for potential use in buccal drug delivery. Biocomposite films composed of gellan gum (GG) and pineapple stem fiber (PSF), with glycerine as a plasticizer, were prepared using the solvent casting method to develop a formulation suitable for this application. Fourier transform infrared (FTIR) spectroscopy, pH and thickness measurements, tensile test, folding endurance, swelling index, scanning electron microscope (SEM), mucoadhesion test and X-ray diffraction (XRD) analysis were conducted to determine the optimal PSF content in the GG-based biocomposite film formulation. The results indicated that the optimal formulation, GG/3PSF, was achieved with the incorporation of 3 wt% PSF relative to the GG mass. Specifically, the GG/3PSF biocomposite film exhibited a tensile strength of 17.10 ± 0.4 MPa (a 50% increase compared to neat GG), an elongation at break of 46.0 ± 2.5%, a tensile toughness of 41 ± 2.0 MPa, and an ex vivo mucoadhesive residence time of at 7.76 ± 0.51 h for GG/3PSF (compared to 3.90 ± 0.24 h for neat GG). Additionally, it maintained a moderate and optimal swelling index of 115.31 ± 2.3% after 60 min of hydration, which prevents structural instability associated with excessive swelling (such as 161.81 ± 4.7% observed in GG/7PSF), while possessing acceptable thickness (0.09 ± 0.005 mm) and neutral pH (7.0 ± 0.05). The developed buccal film is environmentally friendly due to the utilization of pineapple stem fiber, an agricultural by-product that can reduce material costs compared with synthetic fillers and shows considerable potential as a biocomposite film for buccal drug delivery applications.