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<h3>Overview</h3>
<p><strong>FK-506-13C,D2 (Major)</strong> is a stable isotopically labeled analog of Tacrolimus, synthesized via advanced metabolic labeling. It serves as a critical reference standard for pharmacokinetic studies and mass spectrometry quantification. The molecular formula is C44H73NO10 with CAS 159888-64-9.</p>
<h3>Application</h3>
<ul>
<li><strong>Pharmacology:</strong> Used in ADME studies to trace drug metabolism pathways.</li>
<li><strong>Clinical Diagnostics:</strong> Serves as an internal standard for LC-MS/MS assays in therapeutic drug monitoring.</li>
<li><strong>Quality Control:</strong> Validates analytical methods for immunosuppressant purity assessment.</li>
</ul>
<h3>Precautions</h3>
<p>Strictly controlled storage at -20°C under inert atmosphere is required to maintain isotopic integrity. Handling must occur in certified fume hoods due to potent biological activity; personal protective equipment is mandatory to prevent dermal exposure.</p>