EFFECT OF MEMBRANE FILTRATION OF ANTIMALARIAL DRUG SOLUTIONS ON INVITRO ACTIVITY AGAINST PLASMODIUM-FALCIPARUM

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  • 1 January 1984
    • journal article
    • research article
    • Vol. 62  (3) , 439-444
Abstract
Antimalarial activities of chloroquine, mefloquine, amodiaquine, and quinine in vitro against P. falciparum were diminished as a consequence of membrane filtration. Filtered drug solutions gave ID50 [50% inhibitory dose] values up to 25-fold greater than those of nonfiltered (ethanol-sterilized) drug solutions. Loss of activity by filtration was overcome by increasing the drug concentration prior to filtration. Water solutions filtered through Millex-GS filter units consistently showed an absorbance maximum at 277 nm, accompanied by a lesser peak at 225 nm. Water filtrates from Nucleopore and Millex-GV filters showed no absorbance at 277 nm and only slight absorbance was evident for the Gelman filter unit. Activity losses were attributed to extractable contaminating moieties in the membrane filters and/or drug binding to the membrane filters.