Design, Optimization and Evaluation of Taste-Masked Acemetacin Formulations Using Purolite A430MR

A favorable taste is highly desirable for oral formulations, as an unpleasant bitter taste can severely compromise patient compliance. Acemetacin (ACM) is a bitter and poorly soluble drug, posing a significant challenge for oral administration. In this study, Purolite A430MR (A430MR) was employed to mask the bitterness of ACM via a precipitation method, forming ACM-A430MR resin composites (ARCs). A 1:1 weight ratio of ACM to A430MR was identified as the optimized formulation, achieving favorable drug loading and process yield. The ARCs_1:1 was characterized by SEM-EDS, PXRD, DSC, FTIR, and molecular docking to investigate their structural and physicochemical properties and were further evaluated by in vitro release and human sensory testing. The formulation exhibited a drug load of 0.95 mg/mg and a process yield of 65.8%. Characterization revealed that ACM was uniformly dispersed within the resin matrix in an amorphous state, mediated by a salt bridge interaction between the quaternary ammonium group of A430MR and the carboxyl group of ACMs. In vitro release testing showed only 6.04% of ACM was released from ARCs in simulated salivary fluid within 5 min, falling below the 10% threshold generally accepted for effective taste-masking. Human sensory evaluation confirmed a marked reduction in bitterness score from 4.83 (pure ACM) to 1.16 (p < 0.0001). In summary, complexation with Purolite A430MR via ion exchange represents a highly effective taste masking strategy, with strong potential to improve patient compliance.