Bioavailability of acetaminophen containing suppositories in rats

An attempt was made to optimize the rectal delivery of acetaminophen (parac etamol). One of the aims was to determine which of the various lipophilic a nd hydrophilic suppository bases proved to be the best with respect to in v itro drug liberation. Among several experimental vehicles the Witepsol H 15 base with 10 of Miglyol 812 and the Macrogolum 1540 with 5% of Span 20 pro ved to be excellent. Furthermore, a well-known pharmacological effect of th e paracetamol containing suppositories was evaluated in vivo in rats. The a ntipyretic response to the drug depends on the vehicle administered, showin g an excellent correlation between in vitro and in vivo results.