Determination of preservatives in cosmetic products by reversed-phase high-performance liquid chromatography

Industrial application of green chromatography - II. Separation and analysis of preservatives in skincare products using subcritical water chromatography

Several high-temperature liquid chromatography (HTLC) and subcritical water chromatography (SBWC) methods have been successfully developed in this study for separation and analysis of preservatives contained in Olay skincare creams. Efficient separation and quantitative analysis of preservatives have been achieved on four commercially available ZirChrom and Waters XBridge columns at temperatures ranging from 100 to 200°C. The quantification results obtained by both HTLC and SBWC methods developed for preservatives analysis are accurate and reproducible. A large number of replicate HTLC and SBWC runs also indicate no significant system building-up or interference for skincare cream analysis. Compared with traditional HPLC separation carried out at ambient temperature, the HTLC methods can save up to 90% methanol required in the HPLC mobile phase. However, the SBWC methods developed in this project completely eliminated the use of toxic organic solvents required in the HPLC mobile phase, thus saving a significant amount of money and making the environment greener. Although both homemade and commercial systems can accomplish SBWC separations, the SBWC methods using the commercial system for preservative analysis are recommended for industrial applications because they can be directly applied in industrial plant settings.

A novel gradient HPLC method for simultaneous determination of ranitidine, methylparaben and propylparaben in oral liquid pharmaceutical formulation

A selective and accurate high-performance liquid chromatographic method has been developed and validated for the simultaneous determination of ranitidine, methylparaben (MP) and propylparaben (PP) in oral liquids. Samples were purified by solid-phase extraction (SPE) using a copolymeric [poly(divinylbenzene-co-N-vinylpyrrolidone)] sorbent. The chromatographic separation was achieved by HPLC using a mixture of ammonium acetate solution (0.5 M), acetonitrile and methanol as the mobile phase with gradient elution, a Nucleosil C18 column and UV detection at 254 nm. The method was validated with respect to linearity, precision, accuracy, selectivity, and robustness. All the parameters examined met the current recommendations for bioanalytical method validation. The method was found to be applicable to routine analysis (assays and stability tests) of active compound (ranitidine) and preservatives (MP and PP).

Determination of combined p-hydroxy benzoic acid preservatives in a liquid pharmaceutical formulation by HPLC

This paper describes a reversed-phase high performance liquid chromatographic (RP-HPLC) assay method for the determination of combined p-hydroxy benzoic acid (ethylparaben (EP), methylparaben (MP) and propylparaben (PP)) preservatives in a liquid pharmaceutical formulation. The chromatographic separation was achieved with potassium phosphate buffer (pH 7.05)-methanol (47.5:52.5, v/v) as mobile phase, a Spherisorb C(18) column (250 mm x 4.6mm) and UV detection at 254 nm. The analysis time was <8 min. The method was validated with respect to linearity, precision, accuracy, selectivity, specificity and ruggedness. The calibration curves showed good linearity over the concentration range of 2-140 microg/ml. The correlation coefficient were >0.9999 in each case. The relative standard deviation (R.S.D.) values for intra- and inter-day precision studies were <1%. The procedure describe here is simple, selective and is suitable for routine quality control analysis and stability tests.

Optimization by experimental design and artificial neural networks of the ion-interaction reversed-phase liquid chromatographic separation of twenty cosmetic preservatives

Particular attention are recently receiving antimicrobial agents added as preservatives in hygiene and cosmetics commercial products, since some of them are suspected to be harmful to the human health. The preservatives used belong to different classes of chemical species and are generally used in their mixtures. Multi-component methods able to simultaneously determinate species with different chemical structure are therefore highly required in quality control analysis. This paper presents an ion interaction RP-HPLC method for the simultaneous separation of the 20 typical antimicrobial agents most used in cosmetics and hygiene products, that are: benzoic acid, salicylic acid, 4-hydroxybenzoic acid, methyl-, ethyl-, propyl-, butyl-, benzyl-benzoate, methyl-, ethyl-, propyl-, butyl-, benzyl-paraben, o-phenyl-phenol, 4-chloro-m-cresol, triclocarban, dehydroacetic acid, bronopol, sodium pyrithione and chlorhexidine. For the development of the method and the optimization of the chromatographic conditions, an experimental design was planned and models were built by the use of artificial neural network to correlate the retention time of each analyte to the variables and their interactions. The neuronal models developed showed good predictive ability and were used, by a grid search algorithm, to optimize the chromatographic conditions for the separation of the mixture.

Final report on the safety assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate

Benzyl Alcohol is an aromatic alcohol used in a wide variety of cosmetic formulations as a fragrance component, preservative, solvent, and viscosity-decreasing agent. Benzoic Acid is an aromatic acid used in a wide variety of cosmetics as a pH adjuster and preservative. Sodium Benzoate is the sodium salt of Benzoic Acid used as a preservative, also in a wide range of cosmetic product types. Benzyl Alcohol is metabolized to Benzoic Acid, which reacts with glycine and excreted as hippuric acid in the human body. Acceptable daily intakes were established by the World Health Organization at 5 mg/kg for Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate. Benzoic Acid and Sodium Benzoate are generally recognized as safe in foods according to the U.S. Food and Drug Administration. No adverse effects of Benzyl Alcohol were seen in chronic exposure animal studies using rats and mice. Effects of Benzoic Acid and Sodium Benzoate in chronic exposure animal studies were limited to reduced feed intake and reduced growth. Some differences between control and Benzyl Alcohol-treated populations were noted in one reproductive toxicity study using mice, but these were limited to lower maternal body weights and decreased mean litter weights. Another study also noted that fetal weight was decreased compared to controls, but a third study showed no differences between control and Benzyl Alcohol-treated groups. Benzoic Acid was associated with an increased number of resorptions and malformations in hamsters, but there were no reproductive or developmental toxicty findings in studies using mice and rats exposed to Sodium Benzoate, and, likewise, Benzoic Acid was negative in two rat studies. Genotoxicity tests for these ingredients were mostly negative, but there were some assays that were positive. Carcinogenicity studies, however, were negative. Clinical data indicated that these ingredients can produce nonimmunologic contact urticaria and nonimmunologic immediate contact reactions, characterized by the appearance of wheals, erythema, and pruritus. In one study, 5% Benzyl Alcohol elicited a reaction, and in another study, 2% Benzoic Acid did likewise. Benzyl Alcohol, however, was not a sensitizer at 10%, nor was Benzoic Acid a sensitizer at 2%. Recognizing that the nonimmunologic reactions are strictly cutaneous, likely involving a cholinergic mechanism, it was concluded that these ingredients could be used safely at concentrations up to 5%, but that manufacturers should consider the nonimmunologic phenomena when using these ingredients in cosmetic formulations designed for infants and children. Additionally, Benzyl Alcohol was considered safe up to 10% for use in hair dyes. The limited body exposure, the duration of use, and the frequency of use were considered in concluding that the nonimmunologic reactions would not be a concern. Because of the wide variety of product types in which these ingredients may be used, it is likely that inhalation may be a route of exposure. The available safety tests are not considered sufficient to support the safety of these ingredients in formulations where inhalation is a route of exposure. Inhalation toxicity data are needed to complete the safety assessment of these ingredients where inhalation can occur.

Simultaneous analysis of dehydroacetic acid, benzoic acid, sorbic acid and salicylic acid in cosmetic products by solid-phase extraction and high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method for simultaneous determination of dehydroacetic acid (DHA), benzoic acid (BA), sorbic acid (SOA) and salicylic acid (SA) was developed for application to cosmetic products. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-n-butylammonium (TBA) hydroxide as an ion-pair reagent. Cosmetic samples were purified by solid-phase extraction using Bond-Elut SI cartridges. Four acidic preservatives were eluted with methanol from cartridges. The HPLC assay was carried out using TSK gel ODS-80TM column (5 microm, 150 x 4.6 mm I.D.). The mobile phase consisted of a mixture of water and methanol (65:35, v/v) containing 2.5 mM TBA hydroxide adjusted with phosphoric acid to pH 7.0. The calibration curves of these preservatives showed good linearity with UV detection (235 nm). The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2.5 ng for DHA, 4.0 ng for BA, 2.0 ng for SOA and 5.5 ng for SA. The procedure described here is simple, selective and is suitable for quality control of finished cosmetic products.

Microbore liquid chromatography with electrochemical detection for the control of phenolic antioxidants in drugs and foods

Antioxidants are added to foods and drugs to inhibit their oxidation. As these additives are somewhat toxic, it is necessary to control the amount added to any food or drug. Liquid chromatography (LC) is a powerful tool for this purpose. Many antioxidants are electroactive molecules which enables the advantages of electrochemical detection or selectivity and sensitivity to be realized. The interest of analysts in microbore LC arises from the low mobile phase volumetric flow rates involved, the reduced on-column samples together with reduced chromatographic dilution and high efficiency. Coupling of microbore LC with electrochemical detection adds another advantage: the decrease of electrode ageing. The problem of extra-column band broadening with microbore column is discussed in the present communication. A micro LC-electrochemical detection system is constructed and tested using catecholamines. The limit of detection (LOD) for noradrenaline using a 0.7 mm bore column is found to be 0.1 pg injected in 0.2 microliter (0.6 femtomoles). Three phenolic antioxidants are studied: tert-butyl-p-hydroxyanisole (BHA), di-tert-butyl-hydroxytoluene (BHT) and n-propyl gallate (3,4,5-trimethoxybenzoic acid propyl ester). The dynamic range is four orders of magnitude with LODs down to 0.1 femtomoles (20 fg injected) with a 0.3 mm bore column. No electrode response change is observed after 60 injections of 3 ng BHA over 6 days. Antioxidants are determined in different pharmaceutical preparations and foodstuffs (chewing gums, dried potato flakes). The agreement between the manufacturer stated concentrations and observed results is found to be satisfactory.

Determination of preservatives in cosmetic products. II. High-performance liquid chromatographic identification

A high-performance liquid chromatographic (HPLC) procedure is presented for the separation and identification of preservatives that are listed in the current EEC Council Directive on cosmetic products or have been permitted in the past. The method consists of an extraction of acidified cosmetics with methanol, and separation of the extracts by HPLC. Using two isocratic and two gradient reversed-phase HPLC systems, 47 preservatives were characterized by their retention times. The preservatives in three commercial cosmetic products were tentatively identified by the procedure described. The HPLC procedure is suitable for confirmation of the presence of preservatives in cosmetic products as indicated by a previously reported thin-layer chromatographic procedure. In general this method will permit the routine detection of preservatives in cosmetics in an approximate concentration of 0.01% (w/w).

High-performance liquid chromatographic determination of six p-hydroxybenzoic acid esters in cosmetics using Sep-Pak florisil cartridges for sample pre-treatment

A rapid and simple method is described for the simultaneous determination of methyl, ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoic acid esters (parabens) in cosmetics by high-performance liquid chromatography (HPLC). The method involves a single extraction of parabens with diethyl ether and clean-up on a Sep-Pak Florisil cartridge. Fat-soluble excipients in the diethyl ether extracts are removed through the cartridges with hexane-chloroform (75:25). Parabens are then eluted from the cartridges with hexane-ethyl acetate (70:30) and determined by HPLC on a reversed-phase column with water-methanol (50:50) as the mobile phase using sec.-butylpraben as an internal standard. The method was applied to samples with complicated matrices such as cream, milk lotion, lotion and cleansing foam, and the recoveries were 99.0-102.3% with coefficients of variation of 0.3-1.2%.

Studies on the analysis of food additives by high-performance liquid chromatography. V. Simultaneous determination of preservatives and saccharin in foods by ion-pair chromatography

A high-performance liquid chromatographic method for the simultaneous determination of sorbic acid, benzoic acid, p-hydroxybenzoic acid and its methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl esters and saccharin in foodstuffs is described. For good separations of these compounds, acetonitrile-water-0.2 M phosphate buffer pH 3.6 (7:12:1) containing 2 mM cetyltrimethylammonium bromide as an ion-pair reagent and a Nucleosil 5C18 column are required. A steam distillation method and a Sep-Pak C18 cartridge method for the sample preparation are compared. The recoveries from a coffee drink were generally better than 93.8% and the relative standard deviations were 0.85-2.15% for the Sep-Pak C18 cartridge method.