Absorption of penicillin V from mixture formulations. Comparison of potassium and benzathine salts.

The absorption rate and serum level curves of two commercial phenoxymethylpenicillin mixture preparations were compared in adult volunteers. Both the potassium salt (Primcillin) and the benzathine salt (V-Pen ped forte) of V-penicillin were rapidly absorbed and the mean peak serum levels were obtained with both preparations within the first hour after single dose administration. The mean peak level obtained with the potassium salt was several-fold higher (p less than 0.001) and was also reached within a shorter time than that of the benzathine preparation. These results confirm the earlier evidence, obtained with other formulae, for the superior bioavailability of the potassium salt of V-penicillin as compared to most other derivatives used in V-penicillin mixtures.