Water-soluble antimicrobial active

Povidone—iodine is a brown, water-soluble powder containing approximately 10% iodine. However, the amount of free iodine, which is responsible for the antimicrobial activity, is low in a concentrated solution, but is released as the solution is diluted (41). Concentrated solutions have actually been contaminated with bacteria (42). For use as an antiseptic, povidine—iodine is diluted with water or alcohol to a concentration of 1% iodine. Detergents are added if it is used as a surgical scmb. lodophors are important as broad-spectmm antiseptics for the skin, although they do not have the persistent action of some other antiseptics. They are also used as disinfectants for clinical thermometers that have been used by tuberculous patients, for surface disinfection of tables, etc, and for clean equipment in hospitals, food plants, and dairies, much as chlorine disinfectants are used. 

Many derivatives of phenol are now made by a synthetic process. Homologous series of substituted derivatives have been prepared and tested for antimicrobial activity. A combination of alkyl substitution and halogenation has produced useful derivatives including clorinated phenols which are constituents of a number of proprietary disinfectants. Two ofthe most widely used derivatives are/ -chloro-m-cresol (4-chloro-3-methylphenol, chlorocresol, Fig. 10.7C) which is mostly employed as a preservative at a concentration of 0.1%, and / -chloro-m-xylenol (4-chloro-3,5-dimethylphenol, chloroxylenol. Fig. 10.7C) which is used for skin disinfection, although less than formerly. Chloroxylenol is sparingly soluble in water and must be solubihzed, for example in a suitable soap solution in conjunction with terpineol or pine oil. Its antimicrobial capacity is weak and is reduced by the presence of organic matter. 

Extraction and Separation of Alkaloids - The air-dried ground heart-wood (2.2 kg) was extracted by percolation at room temperature with alcohol USP until a negative alkaloid test of the percolate was observed. Removal of the solvent at reduced pressure and at 40° left 71 g of residue that exhibited antimicrobial activity. A 35 g sample of the alcohol-soluble residue was partitioned between 125 ml each of ether and 2Z citric acid In water. The ether layer was extracted twice more with 125 ml of 2% citric acid, filtered to remove some lnterfaclal solids (5.8 g alkaloid negative, no antimicrobial activity), dried (sodium sulfate), and evaporated to dryness, giving 8.6 g of ether solubles that had no antimicrobial activity. 

This aromatic alcohol has been an effective preservative and still is used in several ophthalmic products. Over the years it has proved to be a relatively safe preservative for ophthalmic products [138] and has produced minimal effects in various tests [99,136,139]. In addition to its relatively slower rate of activity, it imposes a number of limitations on the formulation and packaging. It possesses adequate stability when stored at room temperature in an acidic solution, usually about pH 5 or below. If autoclaved for 20-30 minutes at a pH of 5, it will decompose about 30%. The hydrolytic decomposition of chlorobutanol produces hydrochloric acid (HC1), resulting in a decreasing pH as a function of time. As a result, the hydrolysis rate also decreases. Chlorobutanol is generally used at a concentration of 0.5%. Its maximum water solubility is only about 0.7% at room temperature, which may be lowered by active or excipients, and is slow to dissolve. Heat can be used to increase dissolution rate but will also cause some decomposition and loss from sublimation. Concentrations as low as 0.125% have shown antimicrobial activity under the proper conditions. 

Among pharmaceuticals, antibiotics have become of special concern in recent years. The reason is that these substances are continuously being introduced into the environment and may spread and maintain bacterial resistance in the different compartments. Sulfonamides are very commonly used antimicrobials in humans but mainly in veterinary medicine, due to their broad spectrum of activity and low cost, being the second most widely used veterinary antibiotic in the EU. Their occurrence has been reported in all kinds of water matrices their high excretion rates (after their intake by humans of livestock) and high water solubility make them very ubiquitous and persistent pollutants in the environment. 

R. F.Schinazi, R. Sijbesma, G. Srdanov, C. L. Hill, F. Wudl, Synthesis and virucidal activity of a water-soluble, configurationally stable, derivatized C60 fullerene, Antimicrobial Agents and Chemotherapy, vol. 37, pp. 1707-1710,1993. 

A-heterocyclic derivatives of sulphanilamide, e.g. sulphadiazine, sul-phathiazole and sulphoxazole, have broad-spectrum antimicrobial activity. They are generally more water soluble, and thus better absorbed and retained better, i.e. excreted slowly. 

Potassium sorbate has both antimicrobial and antifungal properties in formulations below pH 6. Generally, it is used at concentrations of 0.1% to 0.2% in oral formulations (solutions, syrup, and suspensions), and is used much more than sorbic acid because of its higher solubility and stability in water. However, some loss of antimicrobial activity occurs in the presence of nonionic surfactants and some plastics. 

A zone generally indicates fungicidal activity in the tested sample, but it can mean other things, including the leaching out of the antimicrobial into the colloid base (or partial water solubility), or it can mean volatility of the antimicrobial agent. A zone, therefore, must be interpreted carefully and considered only as one part of the entire picture. 

Parabens are alkyl esters of p-hydroxyben-zoic acid. The alkyl groups may be one of the following methyl, ethyl, propyl, butyl, or heptyl. Parabens are colorless, tasteless, and odorless (except the methyl paraben). They are nonvolatile and nonhygroscopic. Their solubility in water depends on the nature of the alkyl group the longer the alkyl chain length, the lower the solubility. They differ from benzoic acid in that they have antimicrobial activity in both acid and alkaline pH regions. 

Fullerenes Very tiny balls consisting of 60 carbon atoms with diameter of 0.7 nm Water-soluble carboxylic acid Cm derivatives acting as antimicrobials, being linked to a variety of active molecules 25, 38, 39... 

Dowcill 200 (Dow Chemical Co., Midland, MI) is a water-soluble, broad-spectrum antimicrobial and antifungal compound. It is not inactivated by non-ionic, cationic, or anionic formulations, and it is particularly effective against Pseudomonas. Its activity is independent of pH effective concentration is 0.02-0.30%. 

Potassium sorbate has less antimicrobial activity than sorbic acid, but is more water soluble. Most potassium sorbate compounds will contain sorbic acid. A specification for potassium sorbate is contained in the Food Chemicals Codex (FCC). 

The water-soluble and water-insoluble parts of the methanol extract of Achillea sintenisii Hub. Mor. were assayed for their antimicrobial activities against 12 bacteria and 2 yeasts [26]. No activity was exhibited by the water-soluble subfraction, whereas the water-insoluble subtraction of the methanol extract was found to be active against some of the test microorganisms studied. 

A water soluble quaternary ammonium derivative of chitosan (N-(2-hydroxy)propy 1-3 -trimethylammonium chitosan chloride, HTCC) was used as an antimicrobial agent for cotton fabrics. HTCC had a lower minimum inhibition concentration against Staphylococcus aureirs, Klebsiella pneumoiniae and Escherichia coU compared with that of chitosan, but the antimicrobial activity was lost on laundering. However, when cotton fabrics were treated simultaneously with HTCC and polycarboxylic acids (particularly butanetetracarboxylic acid) (BTCA),... 

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