INHIBITORY EFFECTS OF SOLVENT AND SOLID-PHASE EXTRACTION RESIDUES ON MIXED LYMPHOCYTE-CULTURES

Residues from eight solvents/solvent mixtures before and after their p assage through C,,bonded phase columns were assayed for cytostatic act ivity using mixed lymphocyte cultures (MLC). All residues, except thos e from acetonitrile, exhibited cytostatic activity (15%-35% MLC inhibi tion as measured by H-3-thymidine incorporation). Passage of solvents through bonded phase columns contributed an additional and significant cytostatic effect (19%-69% MLC inhibition). Pretreatment of columns w ith methanol led to further increases in the release of cytostatic res idues from the columns, only when followed by less polar solvents (hex ane, ethylacetate, etc.). It is concluded that residues from solid-pha se extraction columns may interfere with subsequent cell culture-based assays for proliferative/antiproliferative activity.