Chlorhexidine

Synonyms:  1,6-bis[N0 -(p-Chlorophenyl)-N 5 -biguanido]hexane; N,N00-bis(4- chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecanediimidamide; chlorhexidini diacetas; chlorhexidini digluconatis solutio; chlorhexidini dihydrochloridum; 1,6-di(40 -chlorophenyldiguanido)hexane; 1,1’-hexamethylene-bis[5-(p-chlorophenyl)biguanide]

Description:  Chlorhexidine occurs as an odorless, bitter tasting, white crystalline powder.

Chemical Name: 1E-2-[6-[[amino-[[amino-[(4 chlorophenyl)amino]methylidene]amino]methylidene]amino]hexyl]-1-[amino [(4-chlorophenyl)amino]methylidene]guanidine

Antimicrobial preservative; antiseptic.

• Chlorhexidine salts are widely used in pharmaceutical formulations in Europe and Japan for their antimicrobial properties.

• Although mainly used as disinfectants, chlorhexidine salts are also used as antimicrobial preservatives.

• As excipients, chlorhexidine salts are mainly used for the preservation of eye-drops at a concentration of 0.01% w/v; generally the acetate or gluconate salt is used for this purpose.

• Solutions containing 0.002–0.006% w/v chlorhexidine gluconate have also been used for the disinfection of hydrophilic contact lenses.

• For skin disinfection, chlorhexidine has been formulated as a 0.5% w/v solution in 70% v/v ethanol and, in conjunction with detergents, as a 4% w/v surgical scrub.

• Chlorhexidine salts may also be used in topical antiseptic creams, mouthwashes, dental gels, and in urology for catheter sterilization and bladder irrigation.

• Chlorhexidine salts have additionally been used as constituents of medicated dressings, dusting powders, sprays, and creams.

Chlorhexidine salts are cationic in solution and are therefore incompatible with soaps and other anionic materials. Chlorhexidine salts are compatible with most cationic and nonionic surfactants, but in high concentrations of surfactant chlorhexidine activity can be substantially reduced owing to micellar binding.

Chlorhexidine and its salts are widely used, primarily as topical disinfectants. As excipients, chlorhexidine salts are mainly used as antimicrobial preservatives in ophthalmic formulations. Animal studies suggest that the acute oral toxicity of chlorhexidine is low, with little or no absorption from the gastrointestinal tract. However, although humans have consumed up to 2 g of chlorhexidine daily for 1 week, without untoward symptoms, chlorhexidine is not generally used as an excipient in orally ingested formulations.

Observe normal precautions appropriate to the circumstances and quantity of material handled. The dust of chlorhexidine and its salts may be irritant to the skin, eyes, and respiratory tract. Gloves, eye protection, and a respirator are recommended.

Chlorhexidine acetate; chlorhexidine gluconate; chlorhexidine hydrochloride.