Diazolidinyl urea (CAS No 78491-02-8) is a preservative widely used in biomedical research It originates from formaldehyde and serves as a formaldehyde releaser effectively inhibiting microbial growth by slowly releasing formaldehyde over time The compound operates by interfering with the microbial cell membrane which prevents bacterial and fungal growth Its in vitro activity spans from nanomolar to low micromolar ranges making it useful for preserving cell cultures and biological samples Diazolidinyl urea is commonly used in vitro and in vivo models including cell lines and animal studies to study its preservative effects and safety It is also utilized in drug screening processes to ensure the stability and longevity of compounds being tested Experimental concentrations typically depend on the specific research design allowing for flexibility in application based on study requirements