Abstract
The preservatives are added to cosmetic preparations in order to prevent or inhibit the growth of micro organism and increase the shelf life of the product. Formaldehyde and methyl paraben are most widely used for this purpose and it is essential to evaluate their limit in newer cosmetic products since they were reported to be toxic while exceeding limits. In the present work formaldehyde was determined from Meswak tooth paste and herbal paste, using a colorimetric method. Methyl paraben was evaluated from Fair & Handsome cream, Dabur Red tooth paste and Ponds fairness cream by a reverse phase HPLC method. The colorimetric method developed for formaldehyde determination is based on aldehyde reaction with acetyl acetone at 40°C and measured at 413nm. An RP-HPLC method employed for methyl paraben was using C18 column with a mobile phase methanol: acetonitrile: water (25:15:60, v/v/v) and detection at 255nm. Preservatives were extracted by respective procedure and evaluated by the analytical methods. The amount of formaldehyde estimated from meswak paste was 0.0066ppm and from herbal paste it was 0.0273ppm. The amount of methyl paraben estimated was 0.036ppm, 0.069ppm and 0.016ppm respectively in Fair & Handsome cream, Dabur Red tooth paste and Ponds fairness cream. The estimated amounts of preservatives in selected cosmetics were found to be within the FDA limit. The two analytical methods developed for the preservatives are precise, accurate and sensitive. They can be employed to evaluate commercially available cosmetics in order to establish their safety for human consumption.
