Intestinal Absorption Characteristics of Sparfloxacin.

The intestinal absorption characteristics of sparfloxacin (5-amino-1-cyclopropyl-7-(cis-3, 5-dimethyl-1-piperazinyl)-6, 8-difluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid, SPFX), a new quinnlone antibacterial agent, was investigated in rats using the in situ ligated loop method and the everted jejunum uptake method in vitro. SPFX was well absorbed from the duodenum, jejunum, ileum and colon, but not from the stomach. The 15-min absorption of SPFX from the jejunum loop was found to be saturable : about 50% of the dose being absorbed at doses of 0.1-lumol/loop and about 15% at 10-30umol/loop. Di-, tripeptides and cyclacillin significantly inhibited the absorption of SPFX by about 40 %, but amino acids did not affect the SPFX absorption. The in vitro uptake of SPFX into the rat everted jejunum was reduced by lowering incubation temperature and by the addition of thiol reagents, di-, tripeptides and aminop-lactam antibiotics. Glycylglycine competitively inhibited the uptake of SPF X. These results suggest that SPFX can be transported by a common dipeptide carrier-mediated system present in the intestinal mucosa. About 40% of SPFX is considered to be absorbed by this system, resulting in good absorption of SPFX from the intestinal tract after oral administration.