Orally-disintegrating tablets of clonidine hydrochloride, an α2-adrenergic agonist, were prepared by the method of drying an aqueous suspension. The suspension was prepared using powdered lactose, and the composition ratio was 2 : 1 (powdered lactose : 0.048% clonidine hydrochloride solution). The suspension was dried under 4±1°C(72±15% R.H.). We obtained tablets containing clonidine hydrochloride (40μg/tablet). Physical properties of the tablets were as follows : hardness was 4.0 kgf, and disintegration time was 41.7 s (in vitro). In the clinical use, 8 patients, aged 1-2 year and weighing 9-11 kg, received approximately 4μg/kg body weight as clonidine hydrochloride. The tablet was administered 90 min before entering the operating room. All patients were willing to accept the tablet. The quality of separation from parents, sedation and a mask acceptance were excellent on all patients. These results suggest that the orally-disintegrating tablet of clonidine hydrochloride was useful in a clinical situation for the preanesthetic medication of pediatric patients aged 1-2 year.
