Abstract
The bacteriostatic effect of sulfapyridin on the pneumococcus in vitro and the inhibitory action of peptone have been shown previously. 1 The findings compare with those reported by Lockwood, 2 who studied the effect of sulfanilamide on the streptococcus under similar conditions. The effect of peptone in preventing drug-action suggested the possibility of an interference in adsorption of the drug. To test this, a study was made of the adsorption of sulfapyridine by activated carbon particles.
Varying amounts of activated carbon were added to solutions containing 10 mg of sulfapyridine and 0.85 g of sodium chloride per 100 cc. After allowing the reaction to take place for 15 minutes, the carbon was removed by filtration, and the filtrate was tested for the presence of the drug by the method described by Marshall. 3 Adsorption was found to occur, as shown in Fig. 1 (solid line).
If 1% peptone (Parke-Davis) is added to the solution containing the drug, and adsorption by carbon allowed to take place, the removal of the drug is retarded. This is shown in Fig. 1 by the broken line. That this adsorption is selective is illustrated by the following experiment: 2 cc of a 1:1000 solution of sulfapyridine were added to 8 cc of saline, and adsorbed with 20 mg of carbon. After 15 minutes, the mixture was divided into 2 parts; to one, 5 cc of 0.85% saline was added, and to the other 0.85% saline containing 1% peptone. These were allowed to stand for another 15 minutes, when they were filtered and tested for sulfapyridine. The portion to which saline had been added showed adsorption of 73% of the drug, as compared with a removal of 55% in the portion to which peptone had been added. This suggests that peptone is able to displace the drug from the surface of the carbon particles.
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