Differential uptake of grepafloxacin by human circulating blood neutrophils and those exudated into tissues

The uptake of the antimicrobial quinolone agent, grepafloxacin, both by hum an circulating blood neutrophils and by those exudated into tissues, was ev aluated in vitro by comparing the intracellular drug concentrations. In cir culating blood neutrophils, the uptake of grepafloxacin was rapid and satur able at 37 degreesC. The uptake of grepafloxacin into circulating blood neu trophils was reduced by lowering the environmental temperature or by the pr esence of metabolic inhibitors, suggesting the involvement of an active tra nsport mechanism. Furthermore, the uptake of grepafloxacin by tissue (saliv ary) neutrophils was also partially temperature-dependent and was significa ntly greater than that by circulating blood neutrophils, i.e. exudation of neutrophils into tissue results in a markedly enhanced transport mechanism for grepafloxacin. This phenomenon may be related to the higher defense act ivity against infection seen in exudated tissue neutrophils. (C) 2001 Elsev ier Science B.V. All rights reserved.