Abstract
The pharmacological actions of PC-904, a new type of semisynthetic penicillin, were investigated.
Summary of pharmacological actions and minimal effective doses (MED) were as follows; fall of blood pressure of the rabbit (50mg/kg), bradycardia from the findings of rabbit ECG (50mg/kg), inhibition of isolated guinea pig atrium (2×10-3g/ml), inhibition of isolated frog heart (10-3g/ml), constriction of isolated rabbit ear vessels (5×10-8g/ml), stimulation of permeability of rabbit skin vessels (100μg), stimulation of isolated rabbit and guinea pig intestine (10-3g/ml and 2×10-3g/ml, respectively), and inhibition of isolated non-pregnant rat uterus (2×10-8g/ml). No effect on respiration of the rabbit and isolated guinea pig trachea (2×10-1g/ml) and isolated pregnant rat uterus (2×10-3g/ml) was observed. No specific action of histamine release by PC-904 from rat peritoneal mast cells was also observed.
MED of PC-904 were much largeer than minimal inhibitory concentrations and maximal blood levels in clinical uses, and were similar to those of ABPC. MED of AB-1405 were smaller than those of PC-904, and MED of A1 were larger than those of PC-904.
When the rat was injected PC-904 once a day for 7 days at doses from 25 to 100mg/kg, urinary excretion of potassium and urinary findings were similar to normal values and those of the control group. Tendency of decreased urinary excretion of sodium was observed.
