Antiseptics and disinfectants

Natthasit TansakulVet.Pharm.KU.

Learning strategies and objectives

• Sit in lecture-class > 80%

• Prepare hand out (Word document and PPT)

• Allow you asking both in/off class

• Discussion and interactive verbal are permitted

• Evaluation Examination (……%; Fill in blank, Multiple choices)

Antiseptics and disinfectants

• Sterilization

- Destroy microbials /may including spores

- Boiling, Oven, Autoclave

• Disinfectant:– Antiseptic: Topical (mucous, tissues),

Spores?– Disinfectant: Using on floor, instruments

Action depending• Chemical properties

• Concentration

• Duration

• Sensitivity of microbials

• Kind of microbials: Bacteria (+/-),Viral

• Environment: pH, Temp, matter

Ideal disinfectants

• Destroy all kind of microbial

• Rapidly action

• Long duration of action

• High stability

• Less or no toxic and adverse effect

• Cheap and easy to use

Disinfectants (Chemical properties)

• Alcohol• Aldehyde• Halogens• Heavy metal• Oxidizing agents• Phenol

• Surface active agents• Acids• Nitrofurazone• Ethylene oxide• Miscellaneous

Disinfectant (Mode of action)• Denature protein and lipid:

– QACs– Acids/ Basic– Alcohols– Phenolics– Biguanides

• Release chemical bond: Aldehydes,Enzymes

• Increase positive ion (Oxidant): Halogens, H2O2, Ozone

Antiseptic agents• Alcohols

• Chlorhexidine

• Oxidizing agents

: Iodine, Iodophors

: Peroxides

- Hydrogen peroxide - Potassium permanganate

• Heavy Metals

:Mercuric bichloride

• Phenols and Related Compounds

• Surface–active compounds

: Soaps

Disinfectant agents

• Oxidizing agents

:Chlorine

• Reducing agents

:Aldehydes

• Surface-active compounds

:QACs

• Vapor-phase Disinfectants

Alcohol• Most used: Ethyl (Ethanol) and

Isopropyl alcohol • Lipid soluble lipoprotein cell

membrane denature cell membrane precipitate protein

• Maximal effect: conc. 70% ethyl and 50% isopropyl alcohol

• Excellent effects: Vegetative both Gr+ and - (Including TB)

• Moderate effects: Lipophilic viruses (herpes simplex, HIV) and Fungi

• Non-effect: Bacterial spores, Hydrophilic viruses

• Organic matter (action)

» I Isopropyl alcohol 70 %

• Most ethanol used at 60-95%, particular 70% w/v is best action

• Not recommend for high level disinfectant

-blood protein denature and adhere to instrument

-prolong use: damage lenses, rubber, plastic instruments

• Rapid evaporation • Limit contact time

• The largest reduction in bacterial count (1-3 min, kill 80% of bact.)

• The safest antiseptic • Adverse effects:

– drying skin– Not for fresh or open wound (irritate)– local irritation– damaging corneal tissue

Biguanides• Chlorhexidine

– Chlorhexidine gluconate

– Bactericidal action

– Rapidly action

– Disrupt the cell membrane and precipitate cell content

– Better against vegetative bacteria gram + than gram –

– Less effective for fungi

– Non effect viruses

– No action on spores

– Chx formulation 4% conc. (most effective)

– The longest residual activity(5-6 hrs.)

– Retained action in organic matter

Oxidizing agents• Bactericidal, short action

• Releasing gas O2: Hydrogen peroxide

• Non releasing gas: Potassium permanganate

• Iodine Oxidizing Antiseptic Halogen releasing agents Chlorine (Disinfectant)

Iodine• Less reactive than chlorine• Rapidly bactericidal(Gr+/-)• Fungicidal, tuberculocidal, virucidal and

sporicidal (Lipophillic)• Interfere metabolic reaction, disrupt protei

n and nucleic acid structure & synthesis• 1-2% iodine solution in 70% ethyl alc. (Tin

cture of iodine) 90%• Aqueous iodine solution 5% (Logol’s

solution) e.g. pyometra• Churchill’s iodine (6.5% Alc.)

• Irritating & allergenic skin, corrssive, delay healing

• Active greater than alcohol

• Indication: antiseptic and disinfectant

• Tip: Iodine 1-2% added to Alc for thermometer disinfectant can increase activity against spores and viruses.

Iodophor• Complexed with a solubilizing agent (surfa

ctant or povidone)

• “iodine carriers” or “iodine-releasing agents”Carrier; Detergents, wetting agents Water soluble

• Increase free iodine releasing

• Act similar to tincture of iodine

• Tissue permeability, enhancing efficacy

• Bactericidal ,verudical , mycobactericidal agent ; act as rapidly as Chx

• Prolong contact time: kill fungi , bact. spores

• Prolong action (4-6 hrs.)

• Retained action in organic matter

• 10 % iodine : maximal killing effect

• 1% minimal toxic

• Less irritating, allergic, corrosive

• Excellent antiseptic and disinfectant

• Indication: skin cleanser, surgical scrub

Hydrogen peroxide• 3-90 % H2O2 in water (Most use 3%)

• Short acting agent but rapidly action

• Bactericidal agent (Gr+/-)

• Lipophillic virus (related catalase and peroxidase enzymes)

• Act as an oxidant by producing hydroxyl free radicals(*OH) attack essential cell components (lipids, proteins, and DNA)

• Act on superficial tissue

• Less toxic but damage tissue

• Indication:– cleaning contaminated wound– deodorizing, not routine cleaning

• Used in the disinfection of soft contact lenses

Potassium permanganate • Antiseptic and disinfectant agents

• Broad antimicrobial agents

• Non releasing gas

• Turn brown colourInactivated

• Intense purple color in solution: stains tissues and clothing brown

• Used for wound and prepare foods

• Effective algicide (0.01%) and virucide (1%)

• Conc.>1:5,000 (irritate tissues)

• Conc 1: 10,000 Bactericidal

Heavy metal• Mercuric chlorideMercuric chloride : merbromin, thimerosal,

nitromersol, phenylmercuric nitrate

• Mercurochrome…..?

• Act as Bacteriostatic

• Inhibit sulfhydryl enzyme of bacterial cells

• Inhibit metabolism and precipitate protein

• Inhibit enzyme action of bacteria and tissues

Thimerosal• Sodium ethylmercurithiosalicylate

• Mercuric 49% w/v

• Inhibit metabolism and precipitate protein

• Merthiolate ™

• Used on fresh wound, not on burn or chronic wound

• Used in preservative vaccine, tattoo ink, skin test agent ect.

Phenol and related compounds• The oldest antiseptic compounds

• Cytoplasmic poisonspenetrating, disruption cell walls

• Bacteriostatic (conc.0.1-1%)

• Bactericidal, fungicidal, virucidal (conc.1-2%)

• Conc 5 % : Kill anthrax spores 48 hr (strongly irritating, corrosively tissues)

• Oral :CNS effects

• Ingestion :Cardiovascular effects

• Main usage : disinfection of equipment

• Cresol (cresylic acid):– Bactericidal agent – less toxic– Commonly used disinfectant (inanimate objec

ts)– Sporicidal Anthrax’s spore– 2 % Cresol (Lysol)

• Chloroxylenols: – Broad-spectrum bactericidal agent– activity against gram + > -– PCMX and DCMX

• Hexachlorophene– Xylenol with composition of Cl-– Strong bacteriostatic action – Most effect on Gr+ > -– Less effect on viruses or spores– Used in medicated soap(conc. 3%), surgical

scrub– May be cause Neurotoxic

• Parachlorometaxylenol (Dettol®)– Aromatic chemical compound in chemistry kno

wn as chloroxylenol– Low toxicity, Low metal corrosivity, – Effective against : Bacteria, Fungi, yeast (3.3

%w/v)– More effective Gr+ than Gr-– Less effect on viruses, fungi and spores– Slow onset action– Mode of action Disrupt the bacterial cells m

embrane and enzyme inactivation

• Tricosan– Bactericidal effect Gr + – Effect : Gr- and yeasts

When combined with EDTA increased permeability of the outer membrane

– Inhibit uptake of essential nutrients on the cytoplasmic membrane

Surface–active compounds

• Soups

• Anionic surface-active agents

• Sodium, Potassium salts of fatty acid

• Most soaps dissolve in water (pH 7.0-10.0)

• Remove dirt from skin surfaces (surface secretion, desquamated epithelium, bacteria)

Disinfectant agentsOxidizing agent:

Chlorine * Gas form is toxic Chemical water soluble forms hypochlorus (HOCl), oganic chloride*Action inhibition of cellular enzymatic reaction, protein deneturation, inactivation of nucleic acids*(HS) Bactericidal, (MS) Fungicidal

(S) Virucidal, Protozoacidal, Sporcidal

• Recommend doses;1-100 ppm (mg/l)• Disadvantages :Corrosively metal, destroy fabric, strongly odor• Quickly react with organic matter

inactivated• Sanitize dairy equipment, hospital

floors, animal, housing quarters

Sodium hypochlorite

• Sodium hypochlorite = NaOCl

• Action as chorline

• Lipid envelope viruses e.g. Avain flu

• Most known as hard-surface disinfection (household bleach)

• Haiter

Reducing agents: AldehydesFormaldehyde

• Liquid form > Gas form

• Slowly action; need contact time 6-12 hrs.

• Act by protein precipitation via Alkylation with alkylating amino and sulhydryl group of protein

• Bactericidal both Gr+ and – and TB

• Virucidal ( e.g FMD)

• Modulate for Fungicidal and Sporicidal agents.

• Formaldehyde 37% on market• Non-corrosively metals, paint, fabric• Combine with Alc :chemical sterilant

for surgical instrument• Low conc.(1ppm) are irritating soft

tissues (eye, nose), pungent odor• Light sensitive (keep in dark)• Carcinogenic agent

Glutaraldehyde• Act as formaldehyde• More efficacy than formaldehyde• Bactericidal(2min), Virucidal, Sporicidal(3

hr),Fungicidal(10 min) action

• Less adverse effect

• Non corrossive Instruments

• Stable in acid• Recommended conc. : 2% w/v• “Cidex” (Glutaraldehyde 2% in 70%

Isopropanol)

• Shelf life 28-30 day

Surface-active compoundsQACs (Quaternary Ammonium

Compounds; cationic detergent) : benzalkonium chloride

• Bacteriostatic or cidal action (Conc?)

• Good efficacy in basic condition

• Denature protein

• Active bact. Gr+ than Gr-

• Inactivated in organic debris, hard water, anionic soap.

• Fungistatic,

• Inactivate viruses (exp. Newer generation)

• Inactivate spores

• Sanitation of non-critical surfaces

Vapor-phase Disinfectants

Ethylene and propylene oxides• Bactericidal,Virucidal, Fungicidal,

Sporicidal agents• Sterilizing animal feed, human food,

surgical equipment • Non-corrosive, flammability• Ethylene oxide > Propylene oxide

Antiseptic usage in Vet. Med.

• Skin cleanser :Presurgical antisepsis *Surgeon-water and soap cleansing -chlohexidine or iodophor hand scrub

*Patient-clip hair and removal gross contamination-gentle antiseptic scrub -antiseptic spay

• Treatment of open wound

-surgical closure bandaging

-application of topical agent( saline, antiseptic, local anesthetic

Basic principle

-don’t harm

-shouldn’t impede healing process

• Teat antisepsis

Rat Haus (City hall)Hannover, Germany