Rate-controlled absorption enhancement of rectally administered cefazolin in rats by a glyceride mixture (MGK).

The enhancing effect of the medium chain glyceride preparation MGK on the rectal absorption of the cephalosporin antibiotic cefazolin sodium was evaluated in relation to the rate of delivery. Cefazolin sodium proved to be absorbed to a small extent (15 to 27%) after rectal administration without MGK. Bolus administration with MGK enhanced rate and extent of cefazolin sodium absorption, resulting in a bioavailability of 57 +/- 26%. Linear infusion of 3 mg cefazolin sodium with MGK in 32 min produced complete absorption of the antibiotic (102 +/- 7%), but absorption occurred slower in comparison with bolus delivery. The rate of administration proved to be an important variable of the absorption enhancing effect of MGK.