INVESTIGATION OF THE ANTIBACTERIAL AND TOXIC ACTION OF CERTAIN ACRIDINE DERIVATIVES

¹ Glaxo Laboratories Ltd., Greenford, Middlesex

1. 2:7-Diaminoacridine monohydrochloride and 5-aminoacridine hydrochloride are active in high dilutions against gram-positive cocci (streptococcus, pneumococcus, staphylococcus) and spore-bearing anaerobes and in lower dilutions against gram-positive and gram-negative bacilli. The presence of blood and serum decreases the activity of both compounds to some extent. They do not neutralise toxin in vitro.

2. Whilst acriflavine is more rapid than 2:7-diaminoacridine monohydrochloride in its bactericidal effect against staphylococcus, it is slower against B. coli and B. proteus. 5-Aminoacridine hydrochloride is the least rapid of the three compounds.

3. In serum, 2:7-diaminoacridine monohydrochloride kills staphylococcus more quickly than do 5-aminoacridine hydrochloride and proflavine; the three compounds are approximately equally effective against B. coli. The salts are in general more rapid in their action than the corresponding bases.

4. 2:7-Diaminoacridine monohydrochloride has a lower, and 5-aminoacridine hydrochloride a higher, systemic toxicity than proflavine, but both compounds are less toxic to tissues than proflavine and acriflavine. The action of the bases on tissues was similar to that of the corresponding salts.

5. The 2:7-compound interfered least with the healing of artificial wounds, whilst the 5-amino-compound was also less harmful than proflavine or acriflavine. The order in which the compounds slowed down the rate of healing was the same whether the substances were applied in solution or in powder form.