Bioavailability of Paediatric Mixtures Containing Phenoxymethylpenicillin Calcium or Potassium Salt

The bioavailability of the calcium and potassium salts of Phenoxymethylpenicillin (dose 38,000 I.U./kg) was investigated in eight healthy adult volunteers. Administration of the calcium salt as an aqueous oral mixture resulted in a mean peak plasma concentration of 8·52 mg/l (SD 1·96) and that of the potassium salt mixture in a concentration of 8·40 mg/ml (SD 2·61), p > 0·1. The median time-to-peak levels were 0·75 h and 1·0 h, respectively (p > 0·1). The mean AUC for the calcium salt mixture was 16·94 mg·h/l (SD 3·31) and for the potassium salt 15·84 mg·h/l (SD 4·76), p > 0·09. These findings confirm that an aqueous mixture of calcium phenoxymethylpenicillin is equivalent to a mixture of potassium Phenoxymethylpenicillin.