Parabens methylparaben

The most frequently used antimicrobials found in commercial shampoos are parabens, methylparaben and propylparaben. Mixtures of different preservatives provide broader protection against a wider spectrum of microorganisms and have been proven to be the most effective method to ensure product robustness [100], The level of preservative necessary depends on the composition of ingredients, total alcohol level, pH value, and water activity. 

Preservatives Parabens (methylparaben, ethylparaben, butylparaben, propylparaben, etc.), EDTA, Formaldehyde, Quaternium 15, Methylisothiazolinone Skin irritation and allergic reactions. Can be neurotoxic. Some, like parabens, are suspected hormone disrupters. Also found in all cosmetics and toiletries. 

Figure 6.4 The CMCs of sodium lauryl sulphate solutions in the presence of alkyl parabens., methylparaben O, ethylparaben x, butylparaben. From Goto and Endo [37] with permission.

Preservatives. Most products must contain preservatives to ensure that yeasts, molds, and bacteria do not thrive in them. These preservatives include alcohol, methylparaben, propylparaben, DMDM hydantoin, diazohdinyl urea, and imidazohdinyl urea. The parabens have limited solubiUty in water, eg, 0.25% for methylparaben and 0.05% for propylparaben (22). If these levels are exceeded in the formula, then the addition of solvents is needed to ensure clear, stable products. 

Parabens are approved for use in oral solution and suspensions at a concentration of 0.015% to 0.2% w/v. Due to their low solubility, the sodium salts of parabens are often used in aqueous formulations. The parabens are most effective in the pH range of 2 to 6, and their antimicrobial activity decreases with increasing pH. Additionally, they are very unstable at pH 8 or above in solution. Methyl paraben has also demonstrated incompatibility with sorbitol and may show some discoloration in the presence of iron. The absorption of methylparaben by plastics has been reported with the amount absorbed being dependent upon the type of plastic and vehicle. However, no absorption has been reported for low density polyethylene (LDPE) or high density polyethylene (HDPE) containers. Certain coloring agents such as yellow iron oxide, ultramarine blue, and aluminum silicate can extensively absorb ethyl paraben in simple aqueous systems, thus reducing its preservative efficacy. 

Fig. 10.5. Separation of parabens with the poly(TBAAm-co-AMPS)-coated column. Conditions column, 750 mm x 25 pm i.d. (600 mm effective length) mobile phase, 20% acetonitrile (v/v) in 50 mMTris-HCl buffer field strength, 400 V/cm injection, 12 kV for 3 s at the side of the anode detection wavelength, 254 nm. Peak identification 1, methylparaben 2, ethylparaben 3, propylparaben 4, butylparaben 5, amylparaben. Reproduced with permission from Sawada and Jinno [11].

Butylparaben is thus more active than methylparaben. Activity may be improved by using combinations of parabens since synergistic effects occur. Activity has also been reported to be improved by the addition of other excipients see Methylparaben for further information. 

Systemically, no adverse reactions to parabens have been reported, although they have been associated with hypersensitivity reactions. See Methylparaben for further information. 

The activity of the parabens increases with increasing chain length of the alkyl moiety, but solubility decreases. Activity may be improved by using combinations of parabens since synergistic effects occur. Ethylparaben is commonly used with methylparaben and propylparaben in oral and topical formulations (such mixtures are commercially available for example, Nipasept (Nipa Laboratories Inc.). Activity has also been reported to be improved by the addition of other excipients see Methylparaben for further information. 

Methylparaben is widely used as an antimicrobial preservative in cosmetics, food products, and pharmaceutical formulations see Table I. It may be used either alone or in combination with other parabens or with other antimicrobial agents. In cosmetics, methylparaben is the most frequently used antimicrobial preservative. ... 

The antimicrobial activity of methylparaben and other para-bens is considerably reduced in the presence of nonionic surfactants, such as polysorbate 80, as a result of micelliza-tion. ° However, propylene glycol (10%) has been shown to potentiate the antimicrobial activity of the parabens in the presence of nonionic surfactants and prevents the interaction between methylparaben and polysorbate 80. ... 

Methylparaben and propylparaben are affirmed GRAS Direct Food Substances in the USA at levels up to 0.1%. All esters except the benzyl ester are allowed for injection in Japan. In cosmetics, the EU and Brazil allow use of each paraben at 0.4%, but the total of all parabens may not exceed 0.8%. The upper limit in Japan is 1.0%. 

Methylparaben and other parabens are widely used as antimicrobial preservatives in cosmetics and oral and topical pharmaceutical formulations. Although parabens have also been used as preservatives in injections and ophthalmic preparations, they are now generally regarded as being unsuitable for these types of formulations owing to the irritant potential of the parabens. These experiences may depend on... 

The EINECS number for methylparaben is 202-785-7. In addition to the most commonly used paraben esters, some other less-common esters have also been used see Table VIII. A specification for methylparaben is contained in the Food Chemicals Codex (FCC). 

Discoloration and/or precipitation occur with various substances, especially phenols, tannins, tars, and tarlike materials. The antimicrobial activity of paraben preservatives is reduced in the presence of polysorbates. See Methylparaben. 

Cosmetic Ingredient Review. 1984. Final report on the safety assessment of methylparaben, ethyl-paraben, propylparaben, andbutylparaben./. Amer. Col. Toxicol. 3 147-209. 

Uniphen P-23. [Induchem AG Lipo] Phenoxyethanol methylparaben, ethyl-paraben, pnq>ylparaben, butylparabm. 

Talcoseptic C. [Vevy] Talc, phen-oxyethanol, methylparaben, ethyl-paraben, propylpar en, bu lparaben. 

FIGURE 15.2 (a) Ion mobility spectrum of a standard solution of methylparaben, ethyl-paraben, propelparaben, butylparaben, and benzylparaben. (b) IMS spectrum of a sample blank. (C) IMS spectrum of a topical cream showing the presences of parabens at the level of approximately 1 mg/g. (From Lokhnauth and Snow, Determination of parabens in pharmaceutical formulations by solid-phase microextraction-ion mobility spectrometry. Anal. Chem. 2005,77, 5938-5946. With permission.)... 

Methylparaben, potassium salt. See Potassium methyl paraben... 

Prepfos. See Pentasodium triphosphate Preserval B. See Benzyl paraben Preserval Butilique. See Butylparaben Preserval E. See Ethyl paraben Preserval M. See Methylparaben Preserval P. See Propylparaben Press-Aid SP] Press-Aid XP. See Synthetic wax... 

Alcohol Benzoic acid Benzyl alcohol Calcium chloride Heptyl paraben Hexamethylenetetramine Lactic acid Methylparaben Myristalkonium chloride ... 

Lauramidopropyl PEG-dimonium chloride phosphate Lauroampho PEG-glycinate phosphate Potassium butyl paraben Potassium ethylparaben Potassium methyl paraben Potassium propylparaben Potassium sorbate Sodium butylparaben Sodium ethylparaben Sodium methylparaben Sodium propylparaben Sucrose myristate bactericide, photographic film Cocamidopropyl hydroxysultaine N,N-Dimethyl-N-lauric acid-amidopropyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyi-N-myristyi-N-(3-suifopropyi)-ammonium betaine N,N-Dimethyi-N-paimityi-N-(3-suifopropyi)-ammonium betaine N,N-Dimethyi-N-stearyi-N-(3-suifopropyi)-ammonium betaine... 

Benzylparaben Potassium butyl paraben Potassium ethylparaben Potassium propylparaben Sodium butylparaben Sodium ethylparaben Sodium methylparaben Sodium propionate Sodium propylparaben Sorbic acid Thiabendazole... 

Olealkonium chloride Phenoxyisopropanol Phenyl benzoate Phenylmercuric acetate Phenylmercuric benzoate Phenylmercuric borate Phenylmercuric bromide Phenylmercuric chloride Phenylparaben o-Phenylphenol Piroctone olamine Polyaminopropyl biguanide Potassium benzoate Potassium butyl paraben Potassium caroate Potassium ethylparaben Potassium metabisulfite . Potassium methylparaben Potassium paraben Potassium o-phenylphenate... 

Potassium propionate Potassium propylparaben Potassium salicylate Potassium sorbate Potassium sulfite Propionic acid Propyl benzoate Propylparaben Quatemium-15 Salicylic acid Silver borosilicate Silver chloride Silver magnesium aluminum phosphate Sodium benzoate Sodium bisulfite Sodium butylparaben Sodium dehydroacetate Sodium ethylparaben Sodium formate Sodium hydroxymethylglycinate Sodium iodate Sodium metabisulfite Sodium methylparaben Sodium paraben Sodium o-phenylphenate... 

Sodium 2-mercaptobenzothiazole Sodium pentachlorophenate Sodium o-phenylphenate Sodium salicylate Thymol Tributyltin acetate Tributyltin oxide Zinc dimethyidithiocarbamate Zinc 2-mercaptobenzothiazole preservative, food-packaging materials Methylparaben Propylparaben preservative, fruit drinks Heptyl paraben... 

Phenylmercuric borate Phenylmercuric nitrate Potassium benzoate Potassium bisulfite Potassium butyl paraben Potassium caroate Potassium ethylparaben Potassium lactate Potassium metabisulfite Potassium methylparaben Potassium propylparaben Potassium salicylate Potassium sorbate Potassium sulfite Propionic acid Propylene glycol Propyl gallate Propylparaben Salicylic acid Sodium ascorbate... 

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