Biotransformation is a critical process in toxicology that involves converting lipophilic chemical substances into hydrophilic derivatives to facilitate excretion. This process is divided into two phases: Phase I (functionalization) and Phase II (conjugation). Phase I reactions introduce or expose functional groups through oxidation, reduction, or hydrolysis, often mediated by enzymes such as the cytochrome P450 family. Phase II reactions involve conjugation with endogenous substrates like glucuronic acid or sulfate, enhancing water solubility.
