Dosage form for Potassium Penicillin G Intravenous Infusion Solutions

Abstract

The chemical stability of potassium penicillin G intravenous infusion solutions is related to the initial pH of the solutions and to the ability of the buffer to maintain a constant pH during aging. It was determined that the 4-5% citrate buffer present in Potassium Penicillin G for Injection, U.S.P. is adequate to maintain the pH at the optimum value of 6.5 when reconstituted for injection. However, the buffer capacity is not adequate to maintain a pH of 6.5 when diluted with a large volume infusion solution. A new dosage form for intravenous infusion is recommended which contains 20% citrate buffer. The recommended dosage form when reconstituted and diluted with either Sodium Chloride Injection, U.S.P. or 5% Dextrose and 0.9% Sodium Chloride Injection, U.S.P. maintains a constant pH and greatly improves the chemical stability of the penicillin. The increased buffer is shown to have little effect on the osmolality of the Infusion solution and is expected to reduce the incidence of phlebitis due to the infusion of acidic solutions.