Factors affecting the activities of microbicides

The antimicrobial activities of microbicides can be profoundly affected by factors such as concentration of the active(s), contact time, temperature, pH, degree and type of soiling, nature and topography of the target surface/object, excipients in the formulation, type and level of microbial contamination and the presence of microbial biofilms. Thus, understanding the influence of these factors, singly or in various combinations, is vital not only to design effective and safer microbicides but also to apply them optimally in the field. Such knowledge is more essential now than ever due to increasing numbers of microbicidal products and their widening applications. Inappropriate and/or sub-optimal use of such products may contribute to human and environmental toxicity and also induce resistance to antibiotics and other microbicides. This chapter is a general review on how the above-mentioned factors may influence the microbicidal activity of chemicals during the initial development of a given formulation, its actual field use and in assessing the outcome of its application