A Review of Circular Pharmaceutics: Plant Mucilage as Tunable Bio-Based Polymers for Advanced Drug Delivery

Plant mucilage is considered here as a tunable polysaccharide platform for drug delivery within a circular approach to materials and manufacturing. Its biphasic architecture of neutral arabinoxylan domains interwoven with an uronate-rich pectic matrix governs hydration, gelation, viscoelastic behavior, and mucoadhesion at relevant solids. These properties can support roles as a disintegrant, film former, rheology modifier, and sustained-release matrix without heavy synthetic crosslinkers. Composition matters measurably. Uronate-to-neutral sugar ratios, branching and acetylation, residual cations, and moisture history map onto junction density and transport, shifting release from barrier control toward coupled diffusion and polymer relaxation. Greener extraction routes receive focused attention. Deep eutectic and natural eutectic solvents, microwave assistance, and ultrasound can raise yield and preserve functionality when solvent recovery, selectivity, and energy use are verified at pilot scale. To make results comparable across cultivars and processes, the review highlights compositionally explicit analytics and small-amplitude oscillatory rheology with uncertainty reporting to define grade-to-function fingerprints. The systems view is practical. Low-value residues supply feedstock. Closed-loop solvent management and pharmacopoeial microbiology underpin quality. Reverse logistics, take-back options, and returnable packaging keep end-of-life in scope alongside release, stability, and safety. Viewed together, these elements show how mucilage can deliver advanced performance with lower waste and credible scale-up for pharmaceutical applications.