Abstract
The suppository for rectal administration of sodium valproate (VPA-Na) was prepared and its clinical effect was investigated in the epileptic patients to whom oral administration was difficult. We prepared two types of suppositories; type A included 600mg of VPA-Na, and type B included equivalent acetic acid in addition to 600mg of VPA-Na. VPA-Na contents in suppositories were determined using HPLC and plasma VPA concentration was determined by fluorescence polarization immunoassay.
The content of VPA-Na in type A suppository gradually decreased to 78% by 4 months when stored in refrigerator, whereas it remained unchanged in type B. When these suppositories were rectally administered to six volunteers, type A showed the mean peak plasma VPA concentration (Cmax) of 16.6μg/ ml and the area under the plasma concentration-time curve from 0 to 8h (AUC 0-8) of 107.6μg·h/ml, and type B showed Cmax of 47.7 μg/ ml and AUG 0-8 of 303.6μg·h/ml. The values of type B were significantly higher than those of type A. To three patients suffering from status epilepticus, type B suppositories were administered at doses of 600mg to 1, 200mg every 8hr, and to four postoperative patients, suppositories were administered at a dose of 600mg for prophylaxis against neurosurgical postoperative epileptic seizure in addition to oral administration of 600mg of VPA-Na. Status epilepticus was well controlled, although small amount of diazepam were also injected. In four patients who underwent neurosurgical operation, the plasma concentration of VPA was maintained within the therapeutic range, and no epileptic seizure was observed. The present study suggests that undissociated VPA suppository is effective for some epileptic patients.
