ABSTRACT
The earth contains 75% water, some of it in pharmaceutical products. In the area of moisture in pharmaceutical products, it is possible to identify three stages in the scientific and regulatory history. The first stage dealt more or less exclusively with the amount of water present in pharmaceuticals, most of which were products of natural origin, with regard to issues of potency and commerce. In the second stage, there was a realization that water could affect the chemical and physical properties of drugs and dosage forms. Chemical Stability of Bioactive Agents Despite recent advances in understanding the influence of moisture on physical state of the solid, it is perhaps the effect of sorbed moisture on the chemical stability of moisture-sensitive drugs that is most important, particularly because many new bioactive agents are expensive moisture-sensitive proteins. The moisture contents stabilized within first few days, and the degradation results are presented as moles of degradation product salicylic acid per mole of water.
