Chemical SterilizationAntiseptics and Disinfectants

Antiseptics:

Chemical agents that are used on the skin and mucous membranes to remove or kill microorganisms.

Antiseptics should be used only on the skin and mucous membranes.

Antiseptics should never be used on instruments or other items or surfaces.

Antiseptics are indicated for

Surgical hand scrub Skin, cervical, and vaginal preparation before a clinical

procedure

Disinfectants:

Used on inanimate objects, such as instruments and surfaces, to kill microorganisms

Examples include chlorine and glutaraldehyde Should be used only for processing instruments and other

items for reuse Indicated for processing instruments and other items and

Cleaning surfaces

Disinfectants are not to be used on the skin or mucous membranes

Instruments and other items should not be left soaking indefinitely or stored in disinfectant solutions.

1) Phenol

Phenol (carbolic acid) is: one of the first chemical agents used as an antiseptic. the standard compound with which other disinfectants are

compared.

Mode of action

Altering selective permeability of the cytoplasmic membrane, causing leakage of vital intracellular substances.

Denature and inactivate proteins (enzymes)

2) Alcohols

Modes of action: -Denaturation of proteins -Lipid solvents – damage the lipid structures within cell membrane -Cleansing or detergent action – mechanical removal.

Practical Application: -Ethyl alcohol – 70%

-Isopropyl alcohol – 90% -Alcohol + iodine – 70% alcohol + 0.5 – 2% iodine -Disinfections of skin, delicate surgical instruments, thermometers -Effective against vegetative MOS -Not effective to bacterial endospores. -Effective against viruses.

3)Halogens

Halogens are strong oxidizing agents are highly reactive and destructive to vital compounds

within the microbial cell. Examples include: Iodine, Chlorine, Bromine (to a leaser

extent) are components of many antimicrobial chemicals.

A)Iodine

Mode of action:-Strong oxidizing agent, it can destroy essential metabolic compounds of MOS through oxidation. -Iodine is rapidly bactericidal, fungicidal, virucidal, and sporicidal -used as antiseptic and disinfectant

b) Chlorine strong oxidizing agent

Bactericidal, sporicidal, virucidal Sodium hypochlorite solutions are widely used for hard-

surface disinfection

4:Heavy Metals and Their Compounds

metals such as mercury, Lead, Zink, Silver, and Copper.

Their action is inactivation of cellular proteins by combining with some components of the protein.

1. Silver Compounds : Silver compounds (e.g., silver

nitrate and silver sulphadiazine) Silver compounds have been used to prevent the

infection of burns and some eye infections2.Mercury – containing – used for the treatment of minor cuts, wounds, and skin infections3.Cupper containing

E.g. Cupper sulfate (CuSO4) – effective as an algicide in open bodies of water

4.Zink – containing – fungicidal and are used in ointments and powders to treat athlete’s foot.

5.Oxidizing agents

Hydrogen peroxide (H2O2) Active against viruses, bacteria and yeast but a higher

concentration (10 – 30%) and long contact time is needed to be sporicidal

Hydrogen peroxide (H2O2) is a widely used for disinfection, sterilization, and antisepsis