Functionality

Functionality

For the growth of bacteria there must be a food supply, moisture, in most cases oxygen, and a certain minimum temperature (see bacteriology). These conditions have been studied and applied in food preservation and the ancient practice of embalming the dead, which is the earliest known systematic use of antiseptics.

In early inquiries, there was much emphasis on the prevention of putrefaction, and procedures were carried out to find how much of an agent must be added to a given solution in order to prevent development of undesirable bacteria. However, for various reasons^[vague], this method was inaccurate, and today an antiseptic is judged by its effect on pure cultures of defined pathogenic celicular single helix microbes and their vegetative and spore forms. The standardization of antiseptics has been implemented in many instances, and a water solution of phenol of a certain fixed strength is now used as the standard to which other antiseptics are compared.

[edit] Some common antiseptics

• Alcohols

  Most commonly used are ethanol (60–90%), 1-propanol (60–70%) and 2-propanol/isopropanol (70–80%) or mixtures of these alcohols. They are commonly referred to as "surgical alcohol". Used to disinfect the skin before injections are given, often along with iodine (tincture of iodine) or some cationic surfactants (benzalkonium chloride 0.05–0.5%, chlorhexidine 0.2–4.0% or octenidine dihydrochloride 0.1–2.0%).

• Quaternary ammonium compounds

  Also known as Quats or QAC's, include the chemicals benzalkonium chloride (BAC), cetyl trimethylammonium bromide (CTMB), cetylpyridinium chloride (Cetrim, CPC) and benzethonium chloride (BZT). Benzalkonium chloride is used in some pre-operative skin disinfectants (conc. 0.05–0.5%) and antiseptic towels. The antimicrobial activity of Quats is inactivated by anionic surfactants, such as soaps. Related disinfectants include chlorhexidine and octenidine.

• Boric acid

  Used in suppositories to treat yeast infections of the vagina, in eyewashes, and as an antiviral to shorten the duration of cold sore attacks. Put into creams for burns. Also common in trace amounts in eye contact solution.

• Brilliant Green

  A triarylmethane dye still widely used as 1% ethanol solution in Eastern Europe and ex-USSR countries for treatment of small wounds and abscesses. Efficient against gram-positive bacteria.

• Chlorhexidine Gluconate

  A biguanidine derivative, used in concentrations of 0.5–4.0% alone or in lower concentrations in combination with other compounds, such as alcohols. Used as a skin antiseptic and to treat inflammation of the gums (gingivitis). The microbicidal action is somewhat slow, but remanent. It is a cationic surfactant, similar to Quats.

• Hydrogen peroxide

  Used as a 6% (20 Vols) solution to clean and deodorize wounds and ulcers. More common 3% solutions of hydrogen peroxide have been used in household first aid for scrapes, etc. However, even this less potent form is no longer recommended for typical wound care as the strong oxidization causes scar formation and increases healing time.^{[citation needed]} Gentle washing with mild soap and water or rinsing a scrape with sterile saline is a better practice.

• Iodine

  Usually used in an alcoholic solution (called tincture of iodine) or as Lugol's iodine solution as a pre- and post-operative antiseptic. No longer recommended to disinfect minor wounds because it induces scar tissue formation and increases healing time. Gentle washing with mild soap and water or rinsing a scrape with sterile saline is a comparatively better practice. Novel iodine antiseptics containing povidone-iodine (an iodophor, complex of povidone, a water-soluble polymer, with triiodide anions I₃^-, containing about 10% of active iodine) are far better tolerated, don't negatively affect wound healing, and leave a deposit of active iodine, thereby creating the so-called "remnant," or persistent, effect. The great advantage of iodine antiseptics is their wide scope of antimicrobial activity, killing all principal pathogens and, given enough time, even spores, which are considered to be the most difficult form of microorganisms to be inactivated by disinfectants and antiseptics.

• Mercurochrome

  Not recognized as safe and effective by the U.S. Food and Drug Administration (FDA) due to concerns about its mercury content. Other obsolete organomercury antiseptics include bis-(phenylmercuric) monohydrogenborate (Famosept).

• Manuka Honey

  Recognized by the U.S. Food and Drug Administration (FDA) as a medical device for use in wounds and burns. Active +15 is equal to a 15% solution of phenol.

• Octenidine dihydrochloride

  A cationic surfactant and bis-(dihydropyridinyl)-decane derivative, used in concentrations of 0.1–2.0%. It is similar in its action to the Quats, but is of somewhat broader spectrum of activity. Octenidine is currently increasingly used in continental Europe as a QAC's and chlorhexidine (with respect to its slow action and concerns about the carcinogenic impurity 4-chloroaniline) substitute in water- or alcohol-based skin, mucosa and wound antiseptic. In aqueous formulations, it is often potentiated with addition of 2-phenoxyethanol.

• Phenol (carbolic acid) compounds

  Phenol is germicidal in strong solution, inhibitory in weaker ones. Used as a "scrub" for pre-operative hand cleansing. Used in the form of a powder as an antiseptic baby powder, where it is dusted onto the navel as it heals. Also used in mouthwashes and throat lozenges, where it has a painkilling effect as well as an antiseptic one. Example: TCP. Other phenolic antiseptics include historically important, but today rarely used (sometimes in dental surgery) thymol, today obsolete hexachlorophene, still used triclosan and sodium 3,5-dibromo-4-hydroxybenzenesulfonate (Dibromol).

• Sodium chloride

  Used as a general cleanser. Also used as an antiseptic mouthwash. Only a weak antiseptic effect, due to hyperosmolality of the solution above 0.9%.

• Sodium hypochlorite

  Used in the past, diluted, neutralized and combined with boric acid in Dakin's solution.

• Calcium hypochlorite

  Used by Semmelweis, as "chlorinated lime", in his revolutionary efforts against childbed fever.

• Sodium bicarbonate (NaHCO3)

  has antiseptic and disinfectant properties.^[5][6]

• Terpenes

  are the main type of compound found in essential oils, and some have reasonably strong antibacterial, antifungal and antiviral properties. For example Terpinen-4-ol is found in Tea tree oil.