Terminalia arjuna gum as a novel biopolymer for microbead formulation in pH-sensitive drug delivery

Biocompatible drug delivery systems that endure stomach acidity while enabling controlled release in the colon are essential for enhancing bioavailability.

This study presents Terminalia arjuna (T. arjuna) gum, a plant-based substitute for synthetic excipients and a natural, biodegradable polymer for controlled drug delivery. It helps create safer, more efficient oral formulations with more stability of acid-labile drugs.

T. arjuna gum was utilized to create plain, blended (T. arjuna gum and sodium alginate were used in a blended formulation to increase stability, drug entrapment, and controlled release), and coated (Propylene glycol and gum mixture was used as the coating material) microbeads via the ionic gelation method.

Characterization showed that the size of plain microbeads was 645.67 ± 7.74 μm, while the size of coated microbeads was 586.23 ± 7.18 μm. Drug entrapment efficiency ranged from 67.06% to 88.12%. Swelling studies in pH 7.4 buffer revealed that coated microbeads had a higher swelling index (1.47 ± 0.09) than blended microbeads (1.18 ± 0.06). In vitro release studies demonstrated sustained release, as predicted by the Korsmeyer-Peppas model, indicating non-Fickian diffusion. Scanning Electron Microscopy (SEM) results revealed spherical microbeads with varying surface morphologies, including rough, porous, and smooth textures, depending on the formulation. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) confirm the stability of microbeads. Powder X-ray Diffraction (PXRD) confirmed the amorphous form of P-Na within the microbeads, and Fourier-Transform Infrared Spectroscopy (FTIR) validated successful drug entrapment without significant interactions with the polymer. Acute toxicity studies on Swiss albino mice showed no adverse effects, and in vivo pharmacokinetic studies in rabbits demonstrated a prolonged P-Na half-life, increasing from 1.12 to 2.24 hrs with a C_max of 2264.8 ng/mL.

These findings suggest that T. arjuna gum-based microbeads are promising candidates for sustained drug delivery applications. Future research should focus on optimizing these formulations for various drugs, exploring additional therapeutic applications, and investigating the long-term stability of T. arjuna gum-based systems for potential clinical use.