Formulation Design of a Hot-melt Extrusion-Based Amorphous Solid Dispersion to Optimize Palatability of Berberine Hydrochloride with In Vitro and In Vivo Evaluation

Berberine hydrochloride (BH) is a naturally isoquinoline alkaloid extracted from Coptis species. It possesses an extremely intense bitter taste and is classified as a Biopharmaceutics Classification System (BCS) class III drug, exhibiting high aqueous solubility but limited intestinal permeability. Conventional taste-masking polymers, including Kollicoat® Smart Seal and Eudragit® EPO, are predominantly gastric-soluble. While effective in suppressing bitterness, their use may delay or reduce drug release in the intestine, potentially exacerbating the inherently low oral bioavailability of BH. To overcome this limitation, this study employed the enteric polymer Kollicoat® MAE 100-55 to develop an amorphous solid dispersion (ASD) designed to achieve taste masking without compromising intestinal drug release. Following formulation screening, an amorphous solid dispersion of berberine hydrochloride (BH-ASD) was successfully prepared via hot-melt extrusion. Simulated salivary dissolution and bitterness assessments demonstrated pronounced taste-masking performance, which was further enhanced by the inclusion of a minor amount of citric acid. Under non-sink conditions in pH 6.8 phosphate-buffered saline, the BH-ASD exhibited a moderately increased apparent solubility. Consistent with these findings, in vivo pharmacokinetic studies showed a 2.21-fold increase in oral bioavailability relative to crystalline BH. Overall, this study offers a promising formulation strategy to mitigate bitterness and enhance oral bioavailability. More importantly, this HME-based ASD platform presents a viable and scalable approach for the development of patient-centric oral dosage forms of BH.