What Is Glutaraldehyde?
Glutaraldehyde is an organic compound classified as a dialdehyde compound.
Its molecular formula is C5H8O2, and in accordance with IUPAC nomenclature, it is called 1,5-pentanedial.
It has a molecular weight of 100.12, a melting point of -14°C, and a boiling point of 71-72°C. It is a colorless or slightly pale yellow liquid at room temperature. It has a pungent odor. The substance is readily soluble in water, alcohol, and acetone.
It is also highly toxic and irritating, and the development of chemical hypersensitivity has been suggested. Because of these toxic properties, glutaraldehyde is a compound subject to various laws and regulations.
Uses of Glutaraldehyde
Glutaraldehyde is used as a fixing solution for electron microscopes, as a leather tanning agent, as a fixing agent for paper and plastic, as a cross-linking agent (hardener) for photographic gelatin, and as a developing agent for radiographic photographs.
Because it has two aldehyde groups, it has strong fixing power and is excellent in maintaining the morphology of microstructures. However, because of its weak permeability in tissues, tissue samples are usually limited to 1 mm square. Furthermore, it requires cooling at 4°C for about 1-2 hours.
Because of its strong sterilizing power, it is used as a chemical sterilization and disinfection agent for medical instruments, equipment, and devices, such as endoscopes and surgical instruments. 2% glutaraldehyde solution and 20% glutaraldehyde solution are approved drugs for medical use, and are effective against almost all bacteria, fungi, spores, and viruses. They are effective against almost all bacteria, fungi, spores, and viruses.
In addition, it is also used as an algaecide for cooling towers and as a disinfectant for poultry houses and poultry farming equipment.
Characteristics of Glutaraldehyde
Glutaraldehyde is relatively unstable when heated and can polymerize. It can also be converted to glutaric acid through oxidation reactions.
Types of Glutaraldehyde
Glutaraldehyde products currently on the market include medical-use pharmaceuticals and reagents for research and development.
As mentioned above, medical-use pharmaceutical products are used as disinfectants for medical instruments, and include 2% glutaraldehyde solution, 20% glutaraldehyde solution, and other types.
Reagent products for research and development are also sold mainly as aqueous solutions, and are available in concentrations of 25% and 50%. The capacities include 25mL, 500mL, 1L, 3L, etc., and are provided in volumes that are easy to handle in the laboratory.
Other Information on Glutaraldehyde
1. Action and Reactivity of Glutaraldehyde
Glutaraldehyde’s action as a fixing and sterilizing solution is due to the high reactivity of its aldehyde groups. When used as a fixing solution in the biological field, the main reaction occurs with the ε-amino group of the lysine residue of proteins, but reactions also occur with the α-amino group and SH group.
These will form intermolecular cross-links and function as a fixing solution. In this case, a single molecule of glutaraldehyde does not form a cross-link by itself, but rather a polymer such as a dimer or trimer formed in aqueous solution or an unsaturated aldehyde formed by aldol condensation is considered to be the reaction-active species.
The mechanism of action of glutaraldehyde when used as a fungicide is believed to be the alkylation of the amino group of the cytoplasm by the aldehyde group of glutaraldehyde.
2. Toxicity of Glutaraldehyde
Glutaraldehyde is highly toxic and irritating, and the following toxicities have been reported. Although no clear carcinogenicity has been reported, the occurrence of chemical hypersensitivity similar to formaldehyde has been noted.
- Harmful if swallowed
- Harmful in contact with skin
- May cause allergy, asthma, or breathing difficulties if inhaled
- May cause serious skin irritation and eye damage
- May cause allergic skin reactions
- Harmful to central nervous system
- May cause respiratory irritation
- May cause airway damage due to long-term or repeated exposure