Parabens polyethylene glycols

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. 

The antibacterial activity of certain antibiotics is reduced in polyethylene glycol bases, particularly that of penicillin and bacitracin. The preservative efficacy of the parabens may also be impaired owing to binding with polyethylene glycols. 

Methyl and propyl paraben Organic peroxides Phenacetin Phenolphthalein Polyethylene glycol Polymers... 

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)... 

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