Anti infectives

• Antisepsis


  Application of an agent to living / animate tissue for the purpose of preventing infection (e.g. alcohol)
• Decontamination


  Destruction or marked reduction in the number of activity of microorganisms
• Disinfection


  Chemical or physical treatment that destroys most vegetative microbes or viruses, but not spores, in or on inanimate surfaces (e.g. alcohol)
• Sanitization


  Reduction of microbial load on an inanimate surface to a level considered acceptable for public health purposes
• Sterilization


  A process intended to kill or remove all types of microorganisms, including spores, and usually including viruses with an acceptably low probability of survival
• Pasteurization


  A process that kills nonsporulating microorganisms by hot water or steam at 65-100℃
• Alcohol


  • Most widely used
  • Kill bacteria, fungi, but not endospores or naked viruses (limitation)
  • Used to mechanically wipe microbes off skin before injections or blood drawing
• Structure Activity Relationship (SAR) of Alcohols

  • Higher number of carbon = greater antimicrobial property (but only until the 8th carbon)
  • Higher primary chain length = greater Van der Waals (VDW) interaction = greater ability to penetrate microbial membranes
  • Higher branching = lesser Van der Waals (VDW) interaction = lesser antimicrobial property
• Alcohol, USP


  • Ethanol (ethyl alcohol, wine spirit)
  • Clear, colorless, volatile liquid with a burning taste and a characteristic pleasant odor
  • Flammable, miscible with water in all proportions, and soluble in most organic solvents
  • Commercial ethanol contains approximately 95% ethanol by volume
  • Chemical formula: C2H6O
  • Can be an antiseptic, base, preservative, counterirritant, and solvent
  • Most widely abused recreational drug
• Denatured Alcohol


  • Ethanol that has been rendered unfit for use in beverages by the addition of other substances
  • Completely denatured alcohol contains added methanol and benzene and is unsuitable for either internal or external use (methanol has a lot of adverse effects from neurological down to seizures and has a separate handling procedure because it is a systemic agent)
• Rubbing Alcohol


  • Comparable to surgical spirit (British Pharmacopeia)
  • Usually contains either isopropyl alcohol or ethanol-based liquids
  • Uses: Astringent, rubefacient, mild local anesthetic
  • USP isopropyl rubbing alcohol contains 70% isopropyl alcohol
  • Famous brand name is family
• Dehydrated Ethanol


  • Absolute alcohol
  • Contains not less than 99% w/w of ethanol
  • Preparation from ethanol-benzene mixture by azeotropic distillation
  • Very high affinity for water and must be stored in tightly sealed containers
  • Used as chemical reagent or solvent
• Isopropyl Alcohol


  • Primarily used as disinfectant for the skin and for surgical instruments
  • Rapidly bactericidal in the concentration range of 50% to 95%
  • 40% concentration is considered equal in antiseptic efficacy to a 60% ethanol in water solution
• Adverse Drug Reaction


  • ADH – alcohol dehydrogenase
  • ALDH – aldehyde dehydrogenase
  • If acetaldehyde accumulates in the body, we will experience hangover side effects such as nausea, vomiting, headache, chest pain, sweating, and vasodilatory flushing
  • Antidote: disulfiram (brand name: antabuse) is used to treat and correct chronic alcoholism by targeting and inhibiting ALDH
• Ethylene Oxide


  • Used to sterilize temperature-sensitive medical equipment and certain pharmaceuticals that cannot be autoclaved
  • Conditions needed to autoclave are 121℃ at 15psi / 30mins
  • Kills all microbes and endospores, but requires exposure of 4 to 18 hours
  • MOA: Alkylation of functional groups in nucleic acids and proteins by nucleophilic ring opening
• Formaldehyde Solution


  • Contains not less than 37% w/w of formaldehyde with methanol added to retard polymerization
  • Polymerization of formaldehyde may produce paraformaldehyde which is not useful enough and needs to be converted back to formaldehyde
  • MOA: Direct and nonspecific alkylation of nucleophilic functional groups of proteins
  • Used extensively to preserve biological specimens and inactivate viruses and bacteria in vaccines
  • Also known as formalin and methanol; simplest aldehyde
  • Irritates mucous membranes, strong odor
  • Adverse effects: Contact dermatitis, GI distress, hardening of the skin, and carcinogenic in pure solution
• Glutaraldehyde


  • Brand name: Cidex
  • Used as a dilute solution for sterilization of equipment and instruments that cannot be autoclaved
  • Less irritating and more effective than formaldehyde
  • Commonly used to sterilize hospital instruments
• Phenol


  • The standard to which most germicidal substances are compared to is the activity of phenol
  • Phenol coefficient: Defined as the ratio of a disinfectant to the dilution of phenol required to kill a given strain of the bacterium Salmonella typhi under carefully controlled conditions over a given period
  • Characteristic "medicinal odor"
  • First introduced by Sir Joseph Lister in 1867 as a surgical antiseptic
  • Almost obsolete as antiseptic and disinfectant
  • Liquefied phenol – phenol containing 10% water
  • Phenol can also denature bacterial proteins at low concentrations, but for the lysis of membranes, it can occur at high concentrations
  • Also known as carbolic acid (old name)
• 1. Chlorophenol


  • Used in combination with camphor in liquid petrolatum as external antiseptic and anti-irritant
  • Phenol coefficient = 4
  • Chlorine group at the para position
• 1. Chloro-m-xylenol


  • Also known as PC-MX
  • Brand name: Metusep
  • Non-irritating antiseptic agent
  • Broad spectrum antibacterial and antifungal properties
  • 2% concentration as shampoo
  • Used topically for the treatment of tinea infections (ringworm)
  • Tinea pedis – Athlete's foot
  • Tinea cruris – Jock itch
  • Tinea corporis – body (corpus)
  • Tinea capitis – scalp
  • Tinea unguium – nails
• Hexachlorophene


  • Increased chlorination increases antiseptic potency
  • Easily adsorbed onto the skin and enters the sebaceous glands
  • Reported neurotoxicity in infants bathed (banned OTC)
• Cresol


  • Mixture of three isomeric methylphenols (ortho, meta, para)
  • Obtained from coal tar or petroleum by alkaline extraction
  • Characteristic odor of creosote (unpleasant odor)
  • Phenol coefficient = 2.5
• Thymol


  • Thymus vulgaris (source)
  • Mint-like odor
  • Mild fungicidal properties and used in alcohol solutions and in dusting powders for the treatment of tinea infections
  • Structure is fish-like
• Eugenol


  • IUPAC name: 4-allyl-2-methoxyphenol
  • Obtained primarily from clove oil (Syzygium aromaticum or Eugenia caryophyllata)
  • Local anesthetic and antiseptic activity / toothache drops
  • Used in mouthwash
• Tinea pedis


  Athlete's foot
• Tinea cruris


  Jock itch
• Tinea corporis


  Body (corpus)
• HEXACHLOROPHENE


  • Increased chlorination increases antiseptic potency
  • Easily adsorbed onto the skin and enters the sebaceous glands
  • Reported neurotoxicity in infants bathed (banned OTC)
• CRESOL


  • Mixture of three isomeric methylphenols (ortho, meta, para)
  • Obtained from coal tar or petroleum by alkaline extraction
  • Characteristic odor of creosote (unpleasant odor)
  • Phenol coefficient = 2.5
• THYMOL


  • Thymus vulgaris (source)
  • Mint-like odor
  • Mild fungicidal properties and used in alcohol solutions and in dusting powders for the treatment of tinea infections
  • Structure is fish-like
• EUGENOL


  • IUPAC name: 4-allyl-2-methoxyphenol
  • Obtained primarily from clove oil (Syzygium aromaticum or Eugenia caryophyllata)
  • Local anesthetic and antiseptic activity / toothache drops
  • Used in mouthwashes
  • Phenol coefficient = 14.4
• RESORCINOL


  • Treatment for skin conditions such as ringworm, eczema, psoriasis, and seborrheic dermatitis
  • Keratolytic agent (softens keratin, exfoliates skin cells)
  • Phenol coefficient = 0.4
• HYDROGEN PEROXIDE


  • Particularly active against anaerobic bacteria and find use in cleansing of contaminated wounds
  • Effectiveness is limited by its poor tissue penetrability and transient action
  • Also known as agua oxigenada (H2O2); oxygen molecules give a bubbling effect
  • Side effect when taken orally is hair tongue
• CARBAMIDE PEROXIDE


  • Brand name: Gly-Oxide (12.6% carbamide peroxide in anhydrous glycerin)
  • Hydrogen peroxide is liberated when mixed with water
  • Used as antiseptic and disinfectant / oral ulcerations and dental care
• HYDROUS BENZOYL PEROXIDE


  • Pure form is explosive
  • Formulated with 30% water to make it safer to handle
  • Compounded at 5% and 10% concentrations
  • Keratolytic and keratogenic agent
  • MOA: Induces proliferation of epithelial cells, leading to sloughing and repair
  • Brand name: Panoxyl
• IODINE


  • One of the oldest known and most effective / useful germicides in use today
  • Iodine tincture: 2% I in 50% alcohol with NaI
  • Strong iodine solution: 5% I in water with KI (Lugol's)
  • Iodine solution: 2% I in water with NaI
  • Iodide salt admixed (increase iodine solubility and decrease volatility)
  • MOA: Inactivate proteins by iodination or aromatic residues
• IODOPHORS


  • Complexes of iodine and nonionic surfactants
  • Such complexes retain the germicidal properties of iodine and also reduce its volatility and essentially removes its irritant properties
  • Bactericidal and fungicidal
• POVIDONE-IODINE


  • Brand name: Betadine
  • A complex with the nonionic surfactant polymer, polyvinylpyrrolidone (PVP)
  • Extremely water soluble and releases iodine very slowly
  • Nontoxic, nonvolatile, non-staining form of iodine, non-irritating to skin or wounds
• HALAZONE


  • Faint chlorine odor
  • Used to disinfect drinking water
  • Slightly soluble in water at pH 7, but very soluble in alkaline solutions
• QUATERNARY AMMONIUM COMPOUNDS


  • Cationic (positively charged) detergents
  • Effective against G(+) bacteria, less effective against G(-) bacteria
  • MOA: Adsorb onto the surface of the bacterial cell, causing lysis
  • Inactivated by soaps and other anion detergents, tissue components, blood, serum, and pus
  • Concentrating with the polar head group and non-polar hydrocarbon chain