Further improvement of orally disintegrating tablets using micronized ethylcellulose.

The aim of this study is to design a new orally disintegrating tablet (ODT) containing micronized ethylcellulose (MEC). The new ODT was prepared by physical mixing of rapidly disintegrating granules (RDGs) with MEC. To obtain RDGs, mannitol was spray-coated with a suspension of corn starch and crospovidone (9:1, w/w ratio) using a fluidized-bed granulator (suspension spray-coating method). The new ODTs were evaluated for their hardness, friability, thickness, internal structure (X-ray-CT scanning), in vivo disintegration time, and water absorption rate. Since MEC increases tablet hardness by increasing the contact frequency between the granules, the new ODTs could obtain high hardness (>50 N) and low friability (<0.5 %) with relatively low compression force. In addition, fine capillary channels formed in ODTs facilitated the wicking action and enabled rapid disintegration in vivo (<30 s). On the other hand, since MEC has low hygroscopicity, the tablet hardness of ODTs containing MEC remained high for 1 month in high-humidity conditions. In conclusion, the new ODTs containing MEC developed in this study possessed superior properties for clinical use and are expected to be applied for a wide range of functionally released drugs for bitter taste masking, sustained release, and controlled release (pH-dependent film coating, matrix, and microcapsule).