Alexander Mackie

A COMPARISON OF THE RESULTS OF FOUR IN VITRO ANTHELMINTIC TESTING TECHNIQUES

INTRODUCTION DURING the last decade the amount of interest in in vitro testing of compounds for anthelmintic activity has increased considerably, mainly because the need for better anthelmintics has become more and more evident, and to find them large numbers of compounds must be screened. Undoubtedly in vitro tests are fundamentally less satisfactory than are in vivo tests ; however, a combination of several techniques obviates some of the objections, and allows more chemicals to be screened, on a preliminary basis, than would in vivo trials against a similar number of nematodes or platyhelminths. In all preliminary screening trials it is essential that the compounds should be tested for anthelmintic effect against several different helminths, because a compound may have no anthelmintic effect on some worms but be effective against others. It is also important, of course, when compounds are tested that none with anthelmintic activity should be missed in the preliminary screening. Furthermore, in vitro testing of compounds for anthelmintic activity has the advantage over in vivo testing in that compounds which would be lethal to the host can be compared, and, therefore, that data can be obtained on chemical structures inducing anthelmintic properties, which would be unobtainable from in vivo tests. This paper compares the results obtained by four of the best known in vitro techniques with 52 compounds ; it also gives the results from some known anthelmintics when they were tested in vitro.