Rosuvastatin-d6 sodium salt is primarily used in research and development as an internal standard in analytical chemistry. It is specifically employed in mass spectrometry and high-performance liquid chromatography (HPLC) studies to quantify and analyze rosuvastatin levels in biological samples. This deuterated compound helps ensure accuracy and precision in pharmacokinetic and metabolic studies, aiding in the understanding of drug behavior in the body. It is also utilized in the development and validation of bioanalytical methods for therapeutic drug monitoring and clinical research.