Accumulation of a newly developed fluoroquinolone, OPC-17116, by human polymorphonuclear leukocytes

The accumulation of OPC-17116 by human polymorphonuclear leukocytes was studied by comparison with three other new quinolones, ofloxacin, levofloxacin, and DR-3354. The intracellular/extracellular concentration ratio was the highest for OPC-17116, being 66.2, followed by 9.8 for levofloxacin, 7.6 for ofloxacin, and 5.8 for DR-3354. Furthermore, it was suggested that the accumulation of these new quinolones was partially related to their active transport system. The elution of OPC-17116 and ofloxacin from cells was rapid, but the elution of OPC-17116 decreased at a high extracellular pH and increased at a low extracellular pH. The accumulation of OPC-17116 as well as that of the other new quinolones was satisfactorily high, thus indicating that they are expected to be useful for the treatment of various kinds of infections, particularly infections caused by cytozoic bacteria.