Stability of Panipenem Injection

Abstract

The purpose of this study was to evaluate the stability of a commercial panipenem injection having a broad spectrum of in vitro antimicrobial activity and its clinical utility in treating serious infections. The effects of temperature and initial panipenem concentration on its stability in the solution media of isotonic sodium chloride solution and glucose injection solution were examined by high-performance liquid chromatography. We also observed the coloration of sample solutions visually.
Temperature was found to be a critical factor determining the degradation rate of panipenem in the injection. The remaining concentrations of panipenem in 0.5 g/100 mL solutions stored at 5, 25, and 40°C for 6 h, were 99, 98, and 89%, respectively, while the corresponding figures for 1.0 g/100 mL solutions were 99, 96, and 80%, respectively. Therefore, the initial concentration also seems to affect the degradation rate. The solution medium did not affect the stability of the panipenem product. The degradation rate increased continuously with time.
The visually observed coloration of samples prepared with 5% (w/v) glucose was greater than that of the corresponding samples prepared with isotonic sodium chloride solution. However, such color changes in the solutions were not sufficiently reliable to be able to determine the extent of panipenem degradation.