Parabens polysorbates

Polysorbate 60 Parabens + bronopol + phenox. Parabens + phenoxyethanol Parabens... 

Preservatives such as sodium benzoate, sorbic acid, and methyl and propyl parabens have been used in liquid and semisolid dosage forms. There have been reports that the parabens have been inactivated when used in the presence of various surfactants. This loss of activity was thought to be due to the formation of complexes between the preservative and the surfactant. The interaction between polysorbate (Tween) 80 and the parabens has been demonstrated by a dialysis technique (Ravin and Radebaugh, 1990). It has also been shown that molecular complexes form when the parabens are mixed with polyethylene glycol (PEG) and methylcellulose. The degree of binding was less than that observed with Tween 80. Sorbic acid also interacts with Tweens but does not interact with PEGs. The quaternary ammonium compounds are also bound by Tween 80, which reduces their preservative activity. 

A typical formulation might include up to 2%i polax-amer 188, up to 0.5% polysorbate 80, up to 0.1% sodium cholate, and up to 1% lecithin, or 3-10%i phospholipids or lecithin. Typically, lipids are more easily processed by homogenization than by bead milling. Nanosuspensions can be preserved with, for example, benzyl alcohol, or methyl paraben and propyl paraben. ... 

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. ... 

Incompatible with oxidizing agents and protein, e.g., serum. Phenylethyl alcohol is partially inactivated by polysorbates, although this is not as great as the reduction in antimicrobial activity that occurs with parabens and polysorbates. ... 

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. 

Blanchard J. Effect of polyols on interaction of paraben preservatives with polysorbate 80./ Pharm Sci 1980 69 169—173. 

Surfactants may be included in an ophthalmic suspension to disperse the drug effectively during manufacture and in the product during use. Non-ionic surfactants are generally preferred because they tend to be less toxic. The level of surfactant included in the formulation should be carefully evaluated, as excessive amounts can lead to irritation in the eye, foaming during manufacture and upon shaking the product, or interactions with other excipients. The most likely interaction is with the preservative. For example, polysorbate 80 interacts with chlorobutanol, benzyl alcohol, parabens and phenyl ethanol and may result in a reduced preservative effectiveness in the product. 

Abbreviations BA benzyl alcohol BHT butylated hydroxytoluene BKC benzalkonium chloride BzCI benethonium chloride CCS croscarmellose sodium cit citric acid dex dextrose IPM isopropyl myristate KP potassium phosphates MCC microcrystalline cellulose MeC methyl cellulose MePB methyl parabens Mr relative molecular mass NaCit Na citrate NaCMC Na carboxymethylcellulose Na2edta disodium edetate NaP sodium phosphate PEG polyethylene glycol PE-OH phenylethyl alcohol PG propylene glycol pov povidone PrPB propyl parabens SAI steroidal anti-inflammatory Tw Tween (polysorbate)... 

The 5% cream contains fluorouracil in a vanishing-cream base consisting of white petrolatum, stearyl alcohol, propylene glycol, polysorbate 60, and parabens (methyl and propyl). 

A different picture arose when the Mayo Clinic examined over 700 eczema patients over a 2-year period for sensitivity to vehicle ingredients (Iden and Schroeter 1977). Here, sensitivity to ethylenediamine reached 7.9%, paraben mixtures in 3.3%, dichlorophene in 2.4%, propylene glycol in 1.5%, lanolin in 1.1%, polysorbate (Tween 20) in 1 %, and sorbic acid in 1 %. In the Danish survey (Hjorth and Trolle Lassen 1963) comprising routine patch testing in 1,664 ecze-... 

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