Validation of moist and dry heat processes used for sterilization and depyrogenation during ampoules manufacturing

Abstract

Pyrogens are fever-producing substances, which are metabolic products of microorganisms and most potent pyrogens are the endotoxins. Depyrogenation can be defined as the elimination of all pyrogenic substances which is an important part of the manufacture of sterile pyrogen free pharmaceutical products. This study compared between sterilization and depyrogenation using moist heat by autoclave, as well as dry heat. After incubation period (24 hours) at 55oC-60oC the color of Geobacillus stearothermophillus spores’ control vial which didn’t sterilized in autoclave changed from blue to yellow color representing the (+ve) result, while the other sterilized vials have no color change (-ve). In addition, all examined endotoxin containing ampoules showed gel formation (+ve) when examined by Limulus Amebocyte Lysate) LAL). All ampoule groups that have autoclaved for periods of 1 hour to 4 hours showed gel formation (+ve) after LAL test, while only the last group which have autoclaving periods of 5 hours (5 cycles) showed no gel formation (-ve). Sterility of vials that contained spores of Geobacillus stearothermophillus after dry heating at 250oC for 30 min showed no color change (-ve). In addition, LAL test for endotoxin containing ampoules after dry heating at 250oC for 30 min showed no gel formation representing -ve pyrogen. So, moist heat is effective in sterilization and not for depydrogenation, whereas, dry heat is effective in sterilization as well as for depyrogenation.