1: Int J Pharm. 2007 Oct 1;343(1-2):4-11. Epub 2007 Apr 24. Irradiation of human insulin in aqueous solution, first step towards radiosterilization. Terryn H, Maquille A, Houée-Levin C, Tilquin B. Laboratory of Chemical and Physicochemical Analysis of Drugs (CHAM), Université Catholique de Louvain, Brussels, Belgium. The degradation of irradiated human insulin in aqueous solutions was investigated in order to protect the protein against ionizing radiation. The influence of the drug concentration, excipients and irradiation temperature were studied. Aqueous solutions at pH 2 were irradiated by gamma rays or by accelerated electrons. Two different high-performance liquid chromatography (HPLC) methods were used: reverse-phase high-performance liquid chromatography (RP-HPLC)/UV and size exclusion liquid chromatography (SEC/UV) to investigate both the fragmentation and the formation of higher molecular weight proteins. In solution without excipients irradiated at ambient temperature at 10 kGy, the loss of human insulin is almost complete. Addition of radio-protecting excipients (free radicals scavengers) and cryo-irradiation allowed to decrease insulin degradation. The best radio-protector used was ascorbic acid in aqueous solution and oxidized glutathione in the frozen solutions. Only the combination of these two approaches (addition of scavenger and freezing) enables the irradiated human insulin in aqueous solution to meet the European Pharmacopoeia requirements for chemical potency (>or=90%). PMID: 17537599 [PubMed - in process] Related Links Chemical analysis of solid-state irradiated human insulin. [Pharm Res. 2006] PMID:16952005 Radiosterilization of drugs in aqueous solutions may be achieved by the use of radioprotective excipients. [Int J Pharm. 2007] PMID:17765417 Influence of histidine on the stability and physical properties of a fully human antibody in aqueous and solid forms. [Pharm Res. 2003] PMID:14725359 Preparation and characterization of microparticles containing peptide produced by a novel process: spray freezing into liquid. [Eur J Pharm Biopharm. 2002] PMID:12191695 The stability of deoxynivalenol and 3-acetyl deoxynivalenol to gamma irradiation. [Food Addit Contam. 1993] PMID:8314397