Assessment of buccal absorption of cilostazol 20% powder in healthy adult male subjects

Cilostazol 20% powder is an orally disintegrated formulation that was newly developed for easier swallowing by patients with swallowing disorders that make it difficult for them to take cilostazol tablets with water. The buccal absorption of cilostazol 20% powder was evaluated in an open-label, randomized, 2-treatment, 2-period crossover study in 14 healthy adult male subjects by comparison of when cilostazol 20% powder was disintegrated in the mouth and swallowed and when it was held in the mouth for 3 minutes without swallowing and then spit out. Although the concentration of cilostazol recovered in the saliva and rinsing water collected from non-swallowing administration was 92.04%, being lower than the criteria of 95%, the mean ratios of the AUC_60h and C_max for non-swallowing administration to those for swallowing administration were respectively 0.05% and 0.08%, both being lower than 5%, the judgment criteria for buccal absorption. As the ratios of the AUC_60h and C_max for non-swallowing administration to those for swallowing administration met the judgment criteria, it was concluded that buccal absorption of cilostazol does not contribute to bioavailability when cilostazol 20% powder is orally administrated.