Bactericidal activity of phenoxymethylpenicillin in an in-vitro model simulating tissue kinetics.

The antibacterial efficacy of phenoxymethylpenicillin (Pen-V-K) against strains of Staphylococcus aureus was assessed in an in-vitro kinetic model. Simulation was based on human serum levels and tissue water curves obtained after a single oral dose of 392.2 mg of the drug.

[Bioavailability of penicillin V in aqueous dosage forms].

The bioavailability of Megacillin-oral-Trockensaft (active substance: potassium salt of phenoxymethylpenicillin, penicillin V potassium) was compared with that of another commercially available drug containing the same active substance. In a cross-over study, 12 healthy volunteers were administered by oral route 10 ml of each preparation (equivalent to 600 000 U = 392.2 mg potassium salt of phenoxymethylpenicillin) under standardized experimental procedure.

Concentration of ampicillin in the vitreous after cryocoagulation.

After transconjunctival cryocoagulation rabbits received 100 mg/kg ampicillin intravenously. At different times in serum, aqueous humor, and in vitreous the concentrations of ampicillin were determined by the agar diffusion method. During the first 90 min after injection the concentration of ampicillin in the vitreous of the treated eyes reached 1 microgram/ml.

[Concentration of ampicillin in the vitreous after photocoagulation of the retina (author's transl)].

After photocoagulation of the retina a higher amount of ampicillin was found in the vitreous of the coagulated eyes, as our tests have shown. The reached concentrations of ampicillin were in the therapeutical region for sensitive germs. The highest concentration of ampicillin was reached when the ampicillin was injected in the edema stage of the coagulation effects.

Comparative studies of the activity of ciclacillin and dicloxacillin.

The penicillins ciclacillin and dicloxacillin demonstrate marked similarities in biological activity but, as far as can be determined, differ substantially in respect to the degree of protein binding, which is relatively low for ciclacillin and relatively high for dicloxacillin. In mice infected with Staphylococcus aureus Smith, ciclacillin is considerably more active than dicloxacillin, although both drugs are similarly effective in vitro and similarly absorbed and eliminated in vivo. The high degree of protein binding exhibited by dicloxacillin could therefore very probably explain its relatively low chemotherapeutic activity.