Used primarily in research and analytical laboratories as an internal standard for the quantification of benzthiazide in various samples. It aids in ensuring accurate and precise measurements in pharmacokinetic studies and drug metabolism research. Its deuterated form allows for differentiation from the non-deuterated compound during mass spectrometry analysis, enhancing the reliability of data in clinical and forensic investigations. Additionally, it supports the development of sensitive and specific analytical methods for monitoring benzthiazide levels in biological matrices.