Study of preparation and utility of suppository containing carbamazepine tablet for hospital use in rabbits

Abstract

Cancer patients often report a decreased quality of life due to cancer-related pain, especially neuropathic pain, which is difficult to manage and often develops resistance to morphine. Thus a supplementary analgesic can play an important role in the treatment of cancer-related pain. Carbamazepine (CBZ), for example, can be effective, but only if the patient can take medication orally because it is limited to oral administration. In this study we investigated the efficacy of a suppository containing CBZ tablet in hospital preparations.We selected a base for the suppository of either polyethylene glycol (P), Witepsol VOSCO®H-15 (H), or Witepsol VOSCO®S-55 (S). Six to eight in vitro and in vivo groups were divided randomly based on route of administration and treatment: intravenous (i.v.), per os (p.o.), and intrarectal administration (i.r.) (composed of CBZ powder and tablet formulations, CBZp and CBZt) prepared in either a base of P, H, or S (CBZp/P, CBZp/H, CBZp/S, CBZt/P, CBZt/H, and CBZt/S). The hardness levels of the CBZt suppository group were significantly lower than the CBZp suppository group. The drug release profiles of the CBZt suppository group were high in order of P, H, and S; there were no significant differences between these groups and the CBZp suppository group. The maximum drug concentration time levels of the CBZt suppository group significantly increased compared with the p.o. group. These two groups had equivalent maximum drug concentration and bioavailability levels. These results suggest that a suppository containing CBZ tablet can be useful for hospital preparations.