An antimicrobial compound that kills bacteria and viruses quickly – found in some of the most colourful antiseptic solutions.
The chemistry in its element podcast curious tales of chemical compounds a bright pink antiseptic solution certainly stands out from the crowd and as mike fremantle discovers the compound at the core of hibiscus and similar colorful cleansers has an important role in modern surgery and a history linked to one of the world’s biggest killers earlier this year
I spent a day in our local hospital i was booked in for a surgical procedure to be carried out on my chest under local anaesthetic before the surgeon made the incision a nurse thoroughly cleaned my chest with an antiseptic solution i asked her what the antiseptic was well hexadeen she replied adding that they used to use an iodine solution i was familiar with
Chlorhexidine my dentist has strongly recommended that i regularly brush my teeth with a dental gel containing the compound to help prevent and treat gum disease chlorhexidine is a type of organic compound known as a biguanide it is used as an antimicrobial ingredient in skin disinfectants creams and wipes wound dressings deodorants and numerous other products
Its development as an antiseptic and disinfectant has a long history during the second world war two british chemists francis kurd and frank rose carried out extensive work at icis research laboratories in manchester on the synthesis of anti-malarial drugs in november 1945 they announced the discovery of a new drug a baiguanide now known as claudeguanide or
Progr it is still used today to treat and prevent malaria kurds life and career were tragically cut short in december 1948 when he died from injuries sustained a few days earlier in a railway accident at stockport cheshire he was 39 years old rose and colleagues at ici however continued to investigate by guanis or dieguanize as they called them in 1954 the
Team reported that one class of substituted by guanis exhibited marked antibacterial activity in vitro against a wide range of microorganisms they compared the activities of 14 of these derivatives and showed that one had the most outstanding properties against bacteria such as staphylococcus aureus the compound which was given the ici trade name hibitain
Is a white crystalline strongly basic solid that is only slightly soluble in water the team therefore used a water-soluble diacetate salt of the compound for their studies two years later rose and his ici co-researcher jeffrey swain described the preparation of water-soluble by hydrochloride salts of hibitain and related by guanis in the paper published in
The journal of the chemical society they noted that hibitain had recently been introduced into medical and veterinary practice under the common name chlorhexidine nowadays the diglucinate sort of chlorhexidine is commonly used in biocide products the chlorhexidine cation has two biguanide moyotes each of which contains five nitrogen atoms and is attached to
A chlorphenol group the compound is therefore sometimes known as abyss by guanide rose and collis called it a bistaguanide confusingly chlorhexidine diglucinate is also referred to as chlorhexadine gluconate the gluconate anion and there are two of them for every chlorhexidine cation in the salt is a derivative of gluconic acid the acid is an open chain form
Of glucose that occurs naturally in fruit honey and wine it is produced commercially by fermenting certain types of fungi chlorhexidine diglucinate and this other source are cationic antiseptics the positively charged chlorhexidine cations bind to the negatively charged cell walls of bacteria the process disrupts the cell membranes allowing the cell contents
To spill out the activity of the salts against bacteria depends on their concentrations low concentrations prevent bacterial reproduction whereas higher concentrations kill the bacteria outright every antiseptic has its pros and cons chlorhexidine salts have a broad spectrum of biocidal activity they exhibit excellent residual activity after being applied
To the skin compared to iodine-based antiseptics which have lower residual activity one recent report indicates that after a two-minute application to the skin chlorhexidine antiseptics continue to kill bacteria for 24 hours they are also fast-acting although not as fast as the ethanol and isopropanol that are currently employed in the ubiquitous alcohol-based
Hand sanitizers chlorhexidine source also exhibit good activity against enveloped viruses the envelopes are outer coatings that protect viral genetic material from the host immune system corona viruses such as the one that causes covert 19 are envelope viruses so to what extent is chlorhexidine used in commercially available hand sanitizers to help prevent
The spread of the disease on a recent shopping expedition to our town center i couldn’t find one over-the-counter hand sanitizer with chlorhexidine in its list of ingredients a few however were available for purchase online there is universal agreement that thoroughly washing your hands with soap and water is the best option for hand hygiene if access to
Soap and water is not available for example at the entrances of shops than almost any commercial hand sanitizer even if it only contains alcohol and water it’s the next best option that was mike fremantle with chlorhexidine next week katrina kramer finds out why a class of solvents may be set to change the world i can say from experience that searching for
The perfect solvent is not something many chemists enjoy so i was surprised to discover that a class of solvents was once voted the british innovation most likely to shape the 21st century sharing the honor with things like the higgs boson 3d printed organs and the raspberry pi computer but what class of solvents could have such an impact find out more with
Katrina next time and until then find all of the compounds that we’ve covered at chemistryworld.com podcasts and let us know if you think we’ve missed something important email chemistryworld rsc.org or tweet at chemistry world i’m ben valzler thank you for joining me
Transcribed from video
Chlorhexidine: Chemistry in its Element podcast By Chemistry WorldliveBroadcastDetails{isLiveNowfalsestartTimestamp2021-01-15T150102+0000endTimestamp2021-01-15T151017+0000}
