Chlorhexidine properties

Examples of preservatives are phenylmercuric nitrate or acetate (0.002% w/v), chlorhexidine acetate (0.01 % w/v), thiomersal (0.01 % w/v) and benzalkorrium chloride (0.01 % w/v). Chlorocresol is too toxic to the comeal epithehum, but 8-hydroxyquinoline and thiomersal may be used in specific instances. The principal considerahon in relation to antimicrobial properties is the activity of the bactericide against Pseudomonas aeruginosa, a major source of serious nosocomial eye infections. Although benzal-konium chloride is probably the most active of the recommended preservatives, it cannot always be used because of its incompatibility with many compounds commonly used to treat eye diseases, nor should it be used to preserve eye-drops containing anaesthetics. Since benzalkonium chloride reacts with natural mbber, silicone or butyl rabber teats should be substituted. Since silicone mbber is permeable to water vapour, products should not be stored for more than 3 months after manufacture. As with all mbber components, the mbber teat should be pre-equilibrated with the preservative prior to... 

Chlorendic acid, 11 479 Chlorendic anhydride, 8 232 CHLOREP program, 25 343 Chlorfenapyr, 14 349 Chlorfluren methyl ester, 13 44t Chlorfurenol methyl ester, 13 44t Chlorhexidine gluconate, 8 340 Chloric acid, 6 103-120 8 544 chemical properties, 6 104 manufacture, 6 104-105 physical properties, 6 103-104 uses, 6 105-106... 

Chlorhexidtne is a symmetrical cationic molecule that is most stable as a salt the highly water-soluble digluconate is the most commonly used preparation. Because of its cationic properties, it binds strongly to hydroxyapatite (the mineral component of tooth enamel), the organic pellicle on the tooth surface, salivary proteins, and bacteria. Much of the chlorhexidine binding in the mouth occurs on the mucous membranes, such as the alveolar and gingival mucosa, from which sites it is slowly released in active form. 

Heard, D.D., and Ashworth, R.W., The collodial properties of chlorhexidine and its interaction with some macromolecules, J. Pharm. Pharmacol. 20, 505-512 (1969). 

It is unclear how growth was actually monitored because QACs are well known to react with the constituents of culture media to produce a dense opalescence or turbidity. Be that as it may, it was also found that resistant and sensitive cells exhibited different surface properties, with the former possessing an increased lipid content. As found by other workers using chlorhexidine, chloroxylenol and other QACs [173, 174], resistance was unstable being lost when the resistant cells were grown in biocide-free media. 

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. 

Senior N. Some observations on the formulation and properties of chlorhexidine. ] Soc Cosmet Chem 1973 24 259-278. 

Roberts WR, Addy M. Gomparlson of the in vivo and in vitro antibacterial properties of antiseptic mouthrinses containing chlorhexidine, alexidine, cetylpyridinium chloride and hexetidine - relevance to mode of action. J Clin Periodontol 1981 8(4) 295-310. 

Jones DS, Woolfson AD, Brown AF. Viscoelastic properties of bioadhesive, chlorhexidine-containing semi-solids for topical application to the oropharynx. Pharm Res 1998 15(7) 1131— 1136. 

Some ingredients of eye medications may increase the permeability of the cornea. Surface-active agents are knovm to interact with membranes to increase the permeability benzalkonium chloride has surfactant properties and may well have some effect on comeal permeability, although its primary purpose is as a bacteriostat and bactericide. Chlorhexidine acetate and cetrimide, both of which are surface-active, are also used. 

Topical 2% povidone iodine solution and 0.2% chlorhexidine gluconate solution have broad antimicrobial profiles and may be used as cheap spectrum and effective antifungal agents in equine ketomycosis, particularly where Fusarium spp. are involved. A1% dermatological cream formulation of silver sulfadiazine has both antifungal and antibacterial properties and is reasonably well tolerated topically in the horse eye. Its use is advocated where cost restraints exist or for prophylaxis in comeal injuries involving embedded plant material (Hamor Whelan 1999). 

Preservatives and disinfectants. Many preservatives and disinfectants can be metabolized by a wide variety of Gram-negative bacteria, although most commonly at concentrations below their effective use levels. Growth of pseudomonads in stock solutions of quaternary ammonium antiseptics and chlorhexidine has resulted in infection of patients. Pseudomonas spp. have metabolized 4-hydroxy-benzoate ester preservatives contained in eye-drops and caused serious eye infections, and have also metabolized the preservatives in oral suspensions and solutions. In selecting suitable preservatives for formulation, a detailed knowledge of the properties of such agents, their susceptibility to contamination and limitations clearly provides invaluable information. 

Both spheroplasts and protoplasts are equally sensitive to lysis by membrane-active agents such as quaternary ammonium compounds (QACs), phenols and chlorhexidine. This demonstrates that the difference in sensitivities of whole cells to these agents is not due to a difference in sensitivity of the target cytoplasmic membrane but in the different permeability properties of the overlying wall or envelope structures. 

Cationic biocides which have strong surface-active properties and which attack the inner (cytoplasmic) membrane, e.g. chlorhexidine and QACs, also damage the outer membrane and thus are believed to mediate their own uptake into the cells. However, the QACs are considerably less active against wild-type than against deep rough strains of Escherichia coli and Salmonella typhimurium. It is clear, then, that the outer membrane must act as a permeability barrier against these compounds. 

This review covers the formation, composition, structure, function and properties of the acquired pellicle. Specifically, the formation of pellicle is considered in terms of thermodynamic and kinetic aspects. The composition of the pellicle is reviewed in terms of the proteins, carbohydrates and lipids that have been identified using a range of analytical techniques. The ultrastructure of the pellicle is described in some detail from studies involving enamel slabs carried in the mouth, in which the subsequent pellicle was analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The function of the pellicle is outlined in terms of its lubrication properties, its ability to act as a semi-permeable membrane and its overall protection of the underlying enamel surfaces. Since pellicle is formed at the interface between the enamel surface and the oral environment, the important process of bacterial attachment to the pellicle surface is described and the specific bacterial binding sites found in the pellicle are summarised. The influence of diet and nutrition on the pellicle layer is considered. The formation of extrinsic stain is discussed in particular, the role that chlorhexidine... 

Addy M, Roberts WR Comparison of the bisguanide antiseptics alexidine and chlorhexidine II. Clinical and in vitro staining properties. J Clin Periodontal 1981 8 220-230. 

FIGURE 10.22 The effect of the incorporation of hexetidine (a) or chlorhexidine (b) on the curing properties of medical grade (tin-catalyzed) silicone. (From Jones, D.S., unpublished data. With permission.)... 

With the role of S. aureus as disease modifier being established, a number of therapeutic approaches may be considered (fig. 2). The potential therapeutic effect of a treatment to eradicate S. aureus in polyp disease or asthma has not been studied yet, but large-scale double-blind placebo-controlled randomized studies are currently ongoing. From atopic dermatitis, a disease sharing the modifying effects of staphylococcal superantigens on inflammation and disease severity, we can deduce therapeutic approaches. The skin of up to 100% of patients with atopic dermatitis is colonized with S. aureus, of which up to 65% have been shown to produce enterotoxins with superantigenic properties. Ten patients were treated orally with antibiotics, chlorhexidine ointment was... 

Four percent chlorhexidine gluconate (CHG) forms the basis for many common presurgical scrubs in use today. These demonstrate high immediate degerming properties and high persistent antimicrobial properties and show good residual antimicrobial effects used both with and without a surgical scrub procedure. ... 

The most commonly used antimicrobial compound that displays strong residual antimicrobial properties is chlorhexidine gluconate (CHG) [4,7]. When products containing CHG are used on the skin repeatedly over time, the bacterial populations decline progressively to levels much lower than the preuse baseline. 

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