Gluteraldehyde

Chemical Name

  • Gluteraldehyde
  • 1,5-pentanedial
  • 1,5-pentanedione
  • glutaric dialdehyde

IUPAC / CAS

Pentanedial / 111-30-8

Physical and Chemical Properties

Gluteraldehyde is a dialdehyde that belongs to the family of Aldehydes and is used as a disinfectant and a cold steriliant (for heat sensitive equipments). It is a colorless water soluble liquid agent with a sharp mint like odor. Its boiling point is 100°C and has a specific gravity of 1.02. Alkaline solutions of gluteraldehyde react with ketones, amines, alcohols and hyrazines.

Mode of Action

Gluteraldehyde reacts with the cell wall components of various micro-organisms. It has better activity at an alkaline pH than acidic pH. When the pH of the external environment becomes alkaline the reactive sites on the cell wall of the micro-organisms open up onto which the gluteraldehyde binds and brings about rapid destruction of the organism.

Activity Spectrum

Gluteraldehyde is a broad spectrum antimicrobial agent with activity against bacteria, spore forms, mycobacteria, viruses, fungi and parasites. Gluteraldehyde forms cross links with the amino groups of proteins present in the cell wall of bacteria. It also inhibits the transport processes and the various enzymes systems of nonsporulating bacteria. It inhibits germination of spores in low concentrations (0.1%) but is sporicidal in high concentrations (2%). The chitin present in the fungal cell wall is its primary target site as a fungicidal agent. With viruses, gluteraldehyde is known to form protein – DNA crosslinkages and irreversible changes in the viral capsid.  Its ability to destroy spores and mycobacteria makes it a useful agent for high level disinfection. It is commonly used as a sterilizing agent especially at low temperatures for heat sensitive equipments like flexible endoscopes and surgical equipment. It is also used as a tissue fixative in electron microscopy.

Advantages

  • Broad spectrumof activity covering vegetative and spore forms of bacteria.
  • Potent mycobactericidal , fungicdal and virucidal activity
  • More stable and less than formalin
  • Noncarcinogenic unlike formaldehyde

Disadvantages

  • Toxic side effects  when exposed to the skin or mucous membranes

Toxicity and Side Effects in Humans

The toxic side effects of gluteraldehyde are limited to occupational exposure with its use as a steriliant and disinfectant. Some of these effects are as follows:

  • Gluteraldehyde can act as a contact allergen causing contact dermatitis
  • Irritation of the eyes causing burning sensation and redness
  • Irritation of the nose and  allergic rhinitis
  • Occupational asthma especially in healthcare workers involved in the disinfection of flexible endoscopes like bronchoscopes and other heat sensitive instruments
  • Staining of the hands (tan brown)
  • Headache , nausea and vomitting is acute cases of exposure

Regulatory Information

  • The National Institute for Occupational Safety and  Health (NIOSH)  laid down a Recommended Exposure Limit (REL) of 0.2 ppm in 1989
  • The American Conference of Governmental Industrial Hygiene (ACGIH) recommends a Threshold Limit Value (TLV) of 0.05ppm in the air.
  • The United Kingdom Health and Safety executive has also established  0.05 ppm as the Workplace Exposure Limit (WEL) for an average duration of 8 hours and 15 minutes.

Safety Measures

To prevent exosure to gluterladehyde vapors the following measures can be taken:

  • Gluteraldehyde baths must be kept under safety hoods
  • Use of automtaed equipments for the  transfer of gluteraldehyde solutions
  • Placing a local exhaust fan at the level of vapor discharge
  • The area where gluteraldehyde is used as a high level disinfectant must be well ventilated with at least 10 air exchanges per hour .
  • Cover containers with gluteraldehyde solutions to prevent the fumes from escaping
  • Use of automated reprocessing instruments for disinfection
  • The odor of gluteraldehyde can be deteced at 0.04ppm and this may be an  indicator towards failing engineering controls, though one must not completely depend on odor detection as products with masking fragrances are also available

To prevent contact with the skin or mucous membranes, following  personal protective equipment must be used:

  • Gloves with elbow level protection made of chemical protective material like nitrile, butyl rubber or Viton must be used. These are impervious to 50% gluteraldehyde solutions are recommended to prevent skin contact.
  • Splash proof goggles with full face sheilds  must be used when handling gluteraldehyde solutions with potential for splashing. A suitable eye wash station must be made available within 10 seconds of distance to wash the eye in case of a splash.
  • If appropritae ventilation engineering controls cannot be provided , the employee must be provided with certified air purifying respirators to prevent vapor exposure.

All those at risk of occupational exposure to gluteraldehyde must attend regular safety training programs and know about the different sources of gluteraldehyde from which they can be exposed.

Gluteraldehyde is readily biodegradebale.Its solutions can be disposed off with copious amounts of cold water to bring about a dilution into the sanitary sewer system. It should not be disposed off into septic systems as it will destroy the bacteria required for the functioning of such a system.

First Aid Treatment

  • In case of skin contact water the area is washed with soap and water for at least 15 minutes.
  • In case of an eyesplash, the eyes must be quickly drenched or flushed with plenty of cold water for atleast 15 minutes at the eye wash station.
  • In the event of a spill, clean it immediately with the help of any absorbent material like sponge, towels, mops etc.Incase of largere spills neutralisation may become essential to reduce the vapor concentration. Some chemicals that can be used are ammonia, ammoinium bicarbonate powder, sodium bisulphite  and dibasic ammonium phosphate. Glycine can also be used as a neutralising agent. A contact time of  5 minutes is required to neutralize the spilled gluteraldehyde.