(P) EVAL. OF THE EFFECTIVENESS OF A STERILANT Flashcards
Used as antiseptics disinfectants
Alcohols and Aldehydes
Antibacterial potencies of the primary alcohols (against test cultures of Staphylococcus aureus)
increase with molecular weight until the ______
8-carbon atom (octanol)
Increased primary alcohol chain length → Stronger Van der Waals interactions → Better membrane penetration
As the alcohol chain lengthens, Van der Waals forces increase, enhancing its ability to disrupt microbial membranes, making it more effective as an antimicrobial agent.
Water solubility decreases → Antimicrobial potency diminishes with higher molecular weight
Longer-chain alcohols become less water-soluble, reducing their ability to diffuse and interact with microbes, which lowers their apparent antimicrobial effectiveness.
Branching of the alcohol chain reduces antibacterial potency
Branched alcohols have weaker Van der Waals interactions, making them less effective at penetrating bacterial membranes, thus decreasing their antimicrobial activity.
Primary > Secondary > Tertiary alcohols in antibacterial effectiveness
• Primary alcohols are the most effective because they have a linear structure, allowing better membrane penetration.
• Secondary and tertiary alcohols are less effective due to their bulkier structures, which hinder interaction with microbial membranes.
is slighlty more active than ethyl alcohol against
vegetative bacterial growth but both are ineffective against spores
Isopropyl alcohol
Denaturation of important proteins and carbohydrates
Mode of Action of Alcohol
• Ethanol, Ethyl Alcohol, Wine Spirit, Spiritus vini rectificatus, Grain Alcohol
• Contains 95% ethanol by volume
• Fermentation product from grain and
other carbohydrates sources
Alcohol, USP
• substance known as ethyl alcohol, hydrated oxide of ethyl, or spirit of wine, from whatever source or
whatever process produced
• having a proof of 160 or more and not including
the substances commonly known as whiskey, brandy, rum or gin.
Alcohol
• the most widely abused of all recreational drugs
• widely used in pharmaceutical preparations
• undergoes a series of oxidation reactions in vivo
Alcohol,USP
Antidote for Alcohol
Disulfiram
• It has been rendered unfit for use in intoxicating beverages by the addition of other substances
Denatured Alcohol
• Completely denatured alcohol contains:
• It is unsuitable for either internal or external use (eye toxicity and bone marrow toxicity/ leukemia,
respectively)
Methanol (wood alcohol) and Benzene
• ethanol treated with one or more substances so that its use may be permitted for a specialized purpose
• Ex:
- iodine in alcohol for tincture of iodine
- methanol, and other substances in mouthwashes
- aftershave lotions
- methanol in alcohol for preparing plant extracts
Specially denatured alcohol
• external as an antiseptic, preservative, mild counterirritant, or solvent
Primary uses of alcohol
• usually contains 70% ethanol
• astringent, rubefacient, refrigerant, mild local anesthetic (results from the evaporative refrigerant action of alcohol when applied to skin)
• has been injected near nerves and ganglia to alleviate pain
• has low narcotic potency and has been used internally in diluted form as mild sedative, a weak vasodilator and a carminative
Rubbing Alcohol
Causes N & V, and vasodilatory flushing
Acetaldehyde
Alcohol used in pharmacy for the preparation of:
• Spirits - preparations containing ethanol as the sole solvent
• Tinctures - hydroalcoholic mixtures
• Fluid Extracts - contain alcohol as cosolvent
% of alcohol that is acceptable bactericidal concentration
70%
% of alcohol that does not have any significant difference in bactericidal action
60 - 95%
% of alcohol that also effective but requires longer contact time
60%
% of alcohol that can be used safely for pre-operative sterilization of the skin
70%
• or Absolute alcohol
• contains not less than 99% ethanol by weight
Dehydrated Alcohol
• primarily used to disinfect the skin and surgical instruments
• rapidly bactericidal in the concentration range of 50% to 95%
• a 40% concentration is considered to be equal in antiseptic power to a 60% ethanol
• 2-propanol
Isopropyl Alcohol
• C2H4O
• used to sterilize temperature- sensitive medical equipment and certain pharmaceuticals that cannot be autoclaved
MOA: ALKYLATION of functional groups in nucleic acids and proteins by nucleophilic ring opening
Ethylene Oxide
• forms explosive mixtures in air at concentrations ranging from 3% to 80% by volume
• explosion hazzard is eliminated when gas is mixed with sufficient concentrations of carbon dioxide (Carboxide®)
• carcinogenic
Ethylene Oxide
• contains not less than 37% of formaldehyde with methanol added to retard polymerization
• disinfectant, embalming fluid
MOA: direct and nonspecific alkylation of nucleophilic functional functional groups of proteins
Formaldehyde Solution (Formalin)
• sterilizing solution for equipment and instruments that cannot be autoclaved (for 30 mins)
Glutarol/ Glutaraldehyde (Cidex®)
• the standard to which most germicidal substances are compared
Phenol, USP
• defined as the ratio of a disinfectant to the dilution of phenol required to kill a given
strain of bacterium Salmonella typhi
• under carefully controlled conditions over a given period
Phenol Coefficient
• Denature bacterial proteins at low concentrations
• Lysis of bacterial cell membranes occurs at higher concentrations
Mode of Action of Phenol,USP
• Carbolic Acid
• was introduced as a surgical antiseptic by
Joseph Lister
• its use as either an antiseptic or disinfectant & is largely obsolete/corrosive to skin (Phenolated Calamine Lotion)
• exhibits germicidal action, caustic to skin, exerts local anesthetic effects
Phenol
• simply phenol containing 10% water
Liquefied Phenol
• used in combination with camphor in liquid petrolatum as an external antiseptic and anti-irritant
p-Chlorophenol
• a non-irritating antiseptic agent with broad-spectrum antibacterial and antifungal properties
• marketed in a 2% concentration as shampoo
• used topically for tinea infections such
as athlete’s foot (tinea pedis) and jock itch (Tinea curis)
p-Chloro-m-xylenol
• used in concentrations 2 to 3% in soaps, detergent creams, lotions, and shampoos for various antiseptic uses
Hexachlorphene
• a mixture of three isomeric cresols
• an inexpensive antiseptic and disinfectant
Cresol
• only useful as preservative
Chlorocresol
• Isopropyl m-cresol
• extracted from oil of Thymus vulgaris (Thyme, of the mint family)
• has mild fungicidal properties and is used in alcohol solutions and in dusting powders for the treatment of tinea (ringworm) infections
Thymol
• 4-Allyl-2-methoxyphenol
• obtained primarily from clove oil
• possesses both local anesthetic and antiseptic activity and can be directly applied on a piece of cotton to relieve toothaches
• also used in mouthwashes because of its antiseptic property and pleasant taste
Eugenol
• m-Dihydroxybenzene (resorcin)
• a weak antiseptic
• used in 1% to 3% solutions and in ointments and pastes in concentrations of 10% to 20% for the treatment of skin conditions such as ringworm, eczema, psoriasis, and seborrheic dermatitis
• a keratolytic agent (causes the stratum corneum of the skin to slough, opening the barrier to penetration for antifungal agents
Resorcinol
• 4-Hexylresorcinol
• an effective antiseptic, possessing both bactericidal and fungicidal properties
• has surfactant properties, local anesthetic activity
• formulated into throat lozenges because of its local anesthetic and antiseptic properties
Hexylresorcinol
• their value as germicides depend upon the liberation of oxygen in the tissues (peroxides) and their ability to denature proteins (permanganates)
• especially effective against anaerobic bacteria and can be used in cleansing wounds
Oxidizing Agents
• bubbles that form during the liberation of oxygen help to dislodge debris
• effectiveness is somewhat limited by its poor penetrability and transient action
Hydrogen Peroxide 2-3%
• Gly-Oxide
• a stable complex of urea and hydrogen peroxide
• liberates hydrogen peroxide when mixed in water
• used as both antiseptic and disinfectant
• preparation is especially effective in the treatment of oral ulcerations or in dental care
Carbamide Peroxide
• Panoxyl® 2.5%, 5%, 10%
• most effective topical OTC agent for the control of acne
• both keratolytic and keratogenic agent
MOA: induces proliferation of epithelial cells, leading to sloughing and repair
S/E: dryness
Hydrous Benzoyl Peroxide
