Improvement of the local tolerance of a potassium penicillin G formulation for injection.

The damaging effect at the injection site (muscle) of a series of different preparations of penicillin C with increasing content of citrate buffer has been investigated in rabbits in order to improve the local tolerance of the drug preparation. The injections were given in M.sacrospinal and 3 days after injection the animals were sacrified and the areas of necrotic muscle tissue were isolated and weighed. The damage from the different preparations was determined on the basis of these weighing results. It was concluded that Novocillin 3.15 g and 6.3 g in 20 ml aqueous solution could be improved by adding 3x the original content of citrate buffer to the preparation resulting in a 38% decrease of the mean weight of necrotic areas at the injection site. Moreover, it was shown that the mean weight of necrotic areas at the injection site was diminished by 41% when injecting the improved 6.3 g concentration in a volume of 0.1 ml compared to injecting the improved 3.15 g concentration in a volume of 0.2 ml, which provides the same dose of penicillin G.