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Disinfectants are chemical agents used to eliminate or reduce harmful microorganisms on surfaces and objects.
They are essential for controlling infections and maintaining hygiene in various settings, including healthcare, laboratories, and public spaces.
Disinfectants can be classified based on their chemical nature and their mode of action.
Classification by Chemical Nature of Disinfectants
1) Alcohols
Examples: Ethanol, Isopropanol
Mode of Action: Denature proteins, disrupt cell membranes.
Use: Commonly used for skin antiseptics and surface disinfection.
2) Aldehydes
Examples: Formaldehyde, Glutaraldehyde
Mode of Action: Cross-linking proteins and nucleic acids, leading to cell death.
Use: Sterilization of medical equipment and instruments.
3) Phenolics
Examples: Phenol, Cresols, Chlorhexidine
Mode of Action: Denature proteins and disrupt cell membranes.
Use: Disinfecting surfaces, particularly in hospitals and laboratories.
4) Halogens
Examples: Chlorine, Iodine, Hypochlorites (bleach)
Mode of Action: Oxidize cellular components, including proteins and nucleic acids.
Use: Water disinfection, surface cleaning, antiseptic solutions.
5) Oxidizing Agents
Examples: Hydrogen Peroxide, Peracetic Acid, Ozone
Mode of Action: Produce free radicals that damage proteins, DNA, and cell membranes.
Use: Sterilizing medical equipment, disinfecting surfaces, and water treatment.
6) Quaternary Ammonium Compounds (Quats)
Examples: Benzalkonium Chloride, Cetylpyridinium Chloride
Mode of Action: Disrupt cell membranes and denature proteins.
Use: Surface disinfectants, antiseptics, and in some sanitizers.
7) Heavy Metals
Examples: Silver Nitrate, Mercuric Chloride
Mode of Action: Bind to proteins and enzymes, inactivating them.
Use: Limited due to toxicity; used in some topical antiseptics and preservatives.
8) Biguanides
Examples: Chlorhexidine, Polyhexanide
Mode of Action: Disrupt cell membranes, leading to leakage of cellular contents.
Use: Skin antiseptics, disinfectants in medical settings.
9) Acids and Alkalis
Examples: Acetic Acid, Lactic Acid, Sodium Hydroxide
Mode of Action: Alter pH, denaturing proteins and disrupting cell membranes.
Use: Food industry, surface disinfection, and cleaning.
Classification by Spectrum of Activity
Broad-Spectrum Disinfectants
Effective against bacteria, viruses, fungi, and spores.
Examples: Bleach (sodium hypochlorite), Glutaraldehyde
Intermediate-Spectrum Disinfectants
Effective against bacteria and enveloped viruses but not non-enveloped viruses or spores.
Examples: Quaternary ammonium compounds, Alcohols
Limited-Spectrum Disinfectants
Effective mainly against bacteria and some enveloped viruses.
Examples: Phenolics, some aldehydes.
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