28-Day Reusable Sterilizing and High-Level Disinfectant Solution for Medical, Surgical, Endoscopic, and Dental Instrumentation. MICRO-CIDE™ 28 HLD is a 3% glutaraldehyde solution with attached powder activator. Once activated, MICRO-CIDE™ 28 HLD can be used for 28 days to provide high level disinfection or sterilization, providing the solution is above the 1.8% minimum effective concentration and is used according to directions for use.