Evaluation of commercial and purified Pluronic® F-68 in a human blood neutrophil bioassay

The effects have been studied of commercial grade Pluronic(R) F-68 or its purified fractions, prepared by passage through silica gel resin (SGR) or by supercritical fluid fractionation (SFF), on human polymorphonuclear leucocyte (PMNL) chemiluminescence in vitro. The mean (+/- s.d., n = 3) total chemiluminescence following stimulation of neutrophils with phorbol 12-myristate 13-acetate in saline controls, was 190 +/- 3 mV x min. Commercial Pluronic(R) inhibited chemiluminescence by a maximum of 26% (P < 0.05), whilst, in contrast, Pluronic(R) F-68 fractions prepared by SGR or SFF stimulated chemiluminescence by up to 53% over control (P< 0.05). The total chemiluminescence with Pluronic(R) F-68 prepared by SA followed by SGR was not significantly. different to that produced by saline (0.9% w/v NaCl). These results reinforce previous suggestions that trace impurities in commercial preparations of the Pluronic(R) F-68 are responsible for reported adverse biological effects.