Development of taste-masked enteric granules containing diclofenac sodium utilizing Eudragit® E PO as a taste-masking agent

This study aimed to develop a taste-masking method for Eudragit® L 100-based enteric microparticles containing diclofenac sodium (DS) using Eudragit® E PO and to determine the optimal polymer ratio for effective taste-masking. The taste-masked enteric granules (TEGs) were fabricated via rotary evaporation with dichloromethane as the solvent, with enteric microparticle-to-Eudragit® E PO weight ratios of 1:0.1, 1:0.25, 1:0.5, and 1:1. Reducing the polymer ratio to 0.1 caused enteric microparticles to disperse independently from the polymer, while higher ratios embedded them in the polymeric carrier. To evaluate the taste-masking efficiency of TEGs, drug release in 10-mL simulated salivary fluid (SSF) was tested. The results revealed that increasing the polymer ratio enhanced the inhibition of drug release in SSF, indicating improved taste masking. However, in the in vitro drug dissolution in a two-stage biorelevant medium, TEGs with high polymer ratios of 1 and 0.5 released only 69.80±1.47% and 78.87±1.21% of DS after 3 h in the buffer stage dissolution, while TEGs with lower polymer ratios of 0.25 and 0.1 exhibited higher drug release percentages of 92.61±1.23% and 97.14±0.58%, respectively. From this study, the optimal enteric particle-to-Eudragit® E PO ratio was 1:0.25, effectively masking the bitter taste of DS while minimally affecting drug release in a gastrointestinal-mimicking environment.