Rectal absorption enhancement of rate-controlled delivered ampicillin sodium by sodium decanoate in conscious rats.

ABSTRACT

Because of the relatively poor intestinal absorption of ampicillin sodium, efforts have been made to enhance ampicillin absorption by co-administration of absorption promoters. In the present study the enhancing effect of sodium decanoate on rate and extent of rectal ampicillin absorption in rats has been evaluated after rate-controlled and site-controlled delivery of aqueous solutions. Rectal absorption without enhancer was extremely low (8 +/- 7%), and the addition of 0.032 M sodium decanoate gave comparable values. However, administration in 0.16 M decanoate considerably increased ampicillin bioavailability, to 79 +/- 30%, whereas the absorption rate was not significantly affected.