Utility of a Rectal Suppository Containing the Antiepileptic Drug Zonisamide

• Published in: Biological & pharmaceutical bulletin Vol. 20; no. 8; pp. 892 - 896
• Main Authors: NAGATOMI, Aki, MISHIMA, Motohiro, TSUZUKI, Osami, OHDO, Shigehiro, HIGUCHI, Shun
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 01.08.1997; Maruzen; Japan Science and Technology Agency
• Subjects: Administration, Oral; Administration, Rectal; Animals; Anticonvulsants - administration & dosage; Anticonvulsants - pharmacokinetics; Anticonvulsants. Antiepileptics. Antiparkinson agents; Area Under Curve; Biological and medical sciences; Biological Availability; drug evaluation; Electroshock; Injections, Intravenous; Isoxazoles - administration & dosage; Isoxazoles - pharmacokinetics; Male; Medical sciences; Mice; Mice, Inbred ICR; Neuropharmacology; pharmacokinetics; Pharmacology. Drug treatments; Rats; Rats, Wistar; rectal suppository; seizure threshold; Suppositories; Zonisamide; Pharmacokinetic pharmacodynamic relationship; Intravenous administration; Rat; Vehicle(excipient); Central nervous system; Variations; Anticonvulsant; Blood brain barrier; Zonisamide; Ethylene oxide polymer; Absorption; Formulation; Release; Rectal form; Sulfonamide; Rodentia; Oral administration; Bioavailability; In vitro; Rectal administration; Biological activity; In vivo; Vertebrata; Mammalia; Animal; Dosage form; Kinetics; Pharmacokinetics; Suppository; Brain (vertebrata)
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.20.892

A suppository of zonisamide (ZNS) was investigated from the viewpoint of pharmaceutical evaluation, pharmacokinetics and pharmacological effect. Two types of ZNS suppositories were prepared. One used Witepsol (H-15 : S-55=3 : 1) as a lipophilic base and the other polyethylene glycol (PEG, 4000 : 1500=4 : 1) as a hydrophilic base. The in vitro release rate of ZNS from the PEG suppository was significantly rapid compared with that of ZNS from Witepsol. Male Wistar rats were administered ZNS (20 mg/kg) using an intravenous, oral or rectal (PEG or Witepsol) route. The absorption of ZNS from the PEG suppository was more rapid than that of ZNS from the Witepsol suppository or from the oral preparation. The peak plasma concentration (Cmax) after a rectal administration of ZNS with Witepsol or PEG suppository was significantly higher than that after the oral administration of ZNS. However, the bioavailability of the three preparations was approximately 100%. Male ICR mice were administered ZNS (80 mg/kg) using the oral or rectal (PEG or Witepsol) route. A positive correlation was observed between the electroshock seizure (ES) threshold and ZNS concentration in plasma or brain. Further, there was no significant difference in the ES threshold or the ZNS concentration in plasma or brain among the three preparations. These results indicate that a ZNS suppository is a very useful preparation from the viewpoint of both pharmacokinetics and pharmacological action.