Improved Dissolution of Poorly Water-Soluble Rutin via Solid Dispersion Prepared Using a Fluid-Bed Coating System

<b>Background/Objectives</b>: Rutin, a bioactive flavonol glycoside known for its antioxidant, anti-inflammatory, and anticancer activities, faces limited clinical application due to its poor aqueous solubility and low oral bioavailability. This study aimed to enhance the dissolution of rutin by preparing solid dispersions (SDs) using a fluid-bed coating system and formulating the resulting SDs into tablet dosage forms. <b>Methods</b>: Rutin was dissolved in methanol and sprayed onto various carriers, including lactose monohydrate, mannitol, microcrystalline cellulose, silicon dioxide, and calcium carbonate. <b>Results</b>: Among the carriers tested, lactose monohydrate produced the highest dissolution enhancement, achieving complete drug release within 15 min versus approximately 60% for free rutin. Further investigation into the effect of the rutin-to-lactose ratio on dissolution enhancement identified 1:10 as the most effective. Characterization by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) confirmed a marked reduction in rutin crystallinity, while scanning electron microscopy (SEM) revealed reduced particle size and successful adsorption onto the carrier. Fourier transformed infrared (FT-IR) analysis suggested hydrogen bonding interactions between rutin and lactose monohydrate, which contributed to improved dissolution. The optimal SD was incorporated into tablets containing 50 mg of rutin via wet granulation, and the inclusion of sodium lauryl sulfate further enhanced dissolution. Stability testing demonstrated that the optimized tablets maintained their dissolution profile after 6 months under accelerated conditions (40 °C and 75% RH). <b>Conclusions</b>: These findings indicate that fluid-bed coating is an effective approach for preparing SDs to improve the dissolution of rutin and may be extended to other natural polyphenolic compounds.