Global Stability Testing and the Confusion Concerning Storage Conditions in Climatic Zone IV Wolfgang Grimm Correspondence: Dr. Wolfgang Grimm, Fohrenweg 5, 88400 Biberach/Riss (Germany); e-mail: wogrimm@aol.com Stability testing is required to ensure safety, quality and efficacy of the drug products up to the end of the shelf life. For global stability testing the earth has been divided into four climatic zones. For the climatic zones I an II (EC, Japan, USA) the requirements are unambiguously described by the ICH Q1AR2 guideline. More complicated is the situation for climatic zone IV, the tropical countries. Different proposals and requirements compete as the definition of the climatic zone IV, the ICH Q1F guideline, ASEAN Consulting Committee, Eastern Mediterranean Region, Brazil and WHO. The different conditions are presented. Further it is described how storage conditions can be evaluated on a scientific base. From the competing storage conditions with relative humidities of 65, 70 and 75 % at 30 °C, 30 °C / 70 % is the preferable and best description for climatic zone IV. Emphasized are the problems of the special storage conditions with low relative humidity for waterbased liquid dosage forms in semi-permeable containers. Finally proposals are given for storage conditions for global stability testing. Key words Stability testing, climatic zone IV, storage conditions |