Preparation, Characterization, and Stability Evaluation of Taste-Masking Lacosamide Microparticles.

Lacosamide (LCM) is a third-generation antiepileptic drug. Selective action of the drug on voltage-gated sodium channels reduces side effects. Oral administration of LCM shows good pharmacokinetic profile. However, the bitter taste of LCM is a barrier to the development of oral formulations. In this study, we aimed to prepare encapsulated LCM microparticles (MPs) for masking its bitter taste. Encapsulated LCM MPs were prepared with Eudragit E100 (E100), a pH-dependent polymer, by spray drying. Three formulations comprising different ratios of LCM and E100 (3:1, 1:1, and 1:3) were prepared. Physicochemical tests showed that LCM was in an amorphous state in the prepared formulations, and they were not miscible. LCM-E100 (1:3) had a rough surface due to surface enrichment of LCM. Increased E100 ratio in LCM-E100 MPs resulted in better taste-making effectiveness: LCM-E100 (1:1) and LCM-E100 (1:3) showed good taste-masking effectiveness, while LCM-E100 (3:1) could not mask the bitter taste of LCM. Dissolution results of the prepared formulations showed good correlation with taste-masking effectiveness. Nevertheless, high E100 ratio reduced the stability of the prepared formulations. Especially the difference in initial dissolution profile observed for LCM-E100 (1:3) indicated rapid reduction in taste-masking effectiveness and surface recrystallization. Therefore, LCM-E100 formulation in the ratio of 1:1 was selected as the best formulation with good taste-masking effectiveness and stability.