Abstract
Antibacterial activity, stability of solution and clinical evaluation of a new semisynthetic penicillin, Apalcillin, were performed. The results obtained are as follows:
1) In vitro antibacterial activity: The minimal inhibitory concentration (MIC) of Apalcillin was measured by an agar plate dilution method using heart infusion agar. Apalcillin had the same antibacterial spectrum as seen with other penicillin antibiotics. The MIC of Apalcillin against 60 strains of Staphylococcus aureus isolated from otorrhoea was distributed over a range of 0.78 to 50μg/ml, with a peak observed particularly at 3.13μg/ml. The MIC of Apalcillin was 0.78 to 50μg/ml against Proteus mirabilis, Escherichia coli and Klebsiella pneumoniae. The MIC against 60 strains of Pseudomonas aeruginosa was 0.78 to 50μg/ml, showing its peak at 3.13μg/ml.
2) Stability of Apalcillin solution: As to the stability of 20mg/ml of Apalcillin there was no change in its colour, pH and antibacterial activity when the solution was kept at 5°C and 37°C for 14 days.
3) Results of clinical treatment: When administration of Apalcillin was applied locally in 30 cases of acute or chronic purulent otitis media, results were good in 22 cases, fair in 6 cases and poor in 2. When good and fair effects were considered together, the rate of effectiveness was 93 per cent. No side effect was observed when Apalcillin solution was locally applied.
