Doxycycline (hyclate) (Standard) is the standard substance of Doxycycline (hyclate), and it is applicable for quantitative analysis, quality control, and related research in biochemical experiments. Doxycycline (hyclate) is an orally active tetracycline antibiotic with broad-spectrum inhibitory activity against matrix metalloproteinases (MMPs), possessing both antibacterial and antitumor properties, and is commonly used in inducible gene expression ON-OFF systems.