Application of a capillary electrophoresis method for simultaneous determination of preservatives in pharmaceutical formulations

Combination of large volume sample stacking with polarity switching and cyclodextrin electrokinetic chromatography (LVSS-PS-CDEKC) for the determination of selected preservatives in pharmaceuticals

In this study, a large volume sample stacking (LVSS) with polarity switching (PS) and cyclodextrin electrokinetic chromatography (CDEKC) method has been developed for the simultaneous separation and determination of 8 preservatives: methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), isobutylparaben (IBP), sorbic acid (SA), benzoic acid (BA), p-hydroxybenzoic acid (PHBA) in pharmaceuticals. The effects of some typical parameters such as sample volume, applied voltage, composition and pH of the running buffer and organic modifier concentration were examined and optimized. Moreover, the impact of type and concentration of cyclodextrin as electrolyte modifiers was also investigated. The detection limits of analytes for the elaborated LVSS-PS-CDEKC method were found to be in 0.8-5 ng mL^-1 range, which were around 500 times lower than normal CDEKC without preconcentration technique. All analytes were completely resolved in less than 11 min in an uncoated fused-silica capillary of 75 μm internal diameter (I.D) x 50 cm length. The electrophoretic separation was performed in a 2 mM α-cyclodextrin and 25 mM tetraborate system (pH = 9.3) with an applied voltage of 25 kV. The established method was validated and confirmed to be applicable for the determination of the preservatives in a quality control of pharmaceuticals.

A survey of parabens in commercial pharmaceuticals from China and its implications for human exposure

Parabens are widely used as antimicrobial preservatives during pharmaceutical production. However, little information is available regarding the occurrence of parabens in commercial pharmaceuticals and their implications for human exposure. In this study, six commonly used parabens were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry with 100 commercial pharmaceuticals collected from China. Almost all of the pharmaceutical samples contained at least one kind of parabens with the detection frequency of 97%. The concentrations of Σ6parabens (sum of the six parabens) ranged from below MDL to 1256ng/g, with mean and median values of 94.8 and 119ng/g, respectively. Methyl paraben (MeP), ethyl paraben (EtP) and propyl paraben (PrP) were the predominant compounds. Significant positive correlation was observed between concentrations of MeP and PrP, indicating their co-applications in pharmaceuticals. Levels of Σ6parabens varied in different categories of pharmaceuticals and increased with their shelf lives. Based on the measured concentrations and daily ingestion rates of pharmaceuticals, the estimated daily intake (EDI) of parabens was calculated. The median values of EDIpharmaceutical for male adults, female adults and children were 4.05, 4.75 and 9.73ng/kg-bw/day, respectively, which were three orders of magnitude lower than those from foodstuffs and personal care products (PCPs). It was firstly reported that the total exposure dose was 0.326mg/kg-bw/day via foodstuffs, PCPs, and pharmaceuticals for Chinese female adults.

Analytical method for the determination and a survey of parabens and their derivatives in pharmaceuticals

Exposure of humans to parabens is a concern due to the estrogenic activity of these compounds. Parabens are widely used as preservatives in some personal care products, foodstuffs and pharmaceuticals owing to their low cost, high water solubility and broad spectrum antimicrobial properties. Despite this, little is known on the occurrence of parabens in pharmaceutical products. In this study, a method based on solid-liquid or liquid-liquid extraction (SLE or LLE), and high performance liquid chromatography (HPLC) coupled with triple quadrupole tandem mass spectrometry (QqQ or MS/MS) was developed for the determination of six most frequently used parabens and four paraben derivatives (methyl- and ethyl-protocatechuates, and mono- and di-hydroxybenzoic acids) in pharmaceuticals. A sample-purification step involving solid phase extraction (SPE) was optimized for the analysis of solid and lipid-rich pharmaceuticals. To our knowledge, this is the first comprehensive report on the occurrence of parabens in pharmaceuticals. The developed method was applied for the analysis of 128 liquid/syrup, cream, solid, prescription or over-the counter (OTC) drugs collected from the USA and a few other countries in Europe and Asia. Although majority of the drugs analyzed in the study did not contain parabens, concentrations as high as 2 mg/g were found in some drugs. Methyl- and propyl- parabens were the frequently detected compounds. 4-Hydroxybenzoic acid was the major metabolite found in pharmaceutical products.

Determination of additives in cosmetics by supercritical fluid extraction on-line headspace solid-phase microextraction combined with gas chromatography-mass spectrometry

A new hyphenated technique couples supercritical fluid extraction in situ derivatization and on-line headspace solid-phase microextraction to gas chromatography-mass spectrometry (SFE in situ derivatization on-line HS-SPME-GC-MS) for the determination of paraben preservatives and polyphenolic antioxidants in cosmetics. The preservatives and antioxidants were extracted from the cosmetic matrices with supercritical carbon dioxide at a pressure of 13,840 kPa. The supercritical fluid extraction was performed at 55 degrees C for 10 min of static extraction then 15 min of dynamic extraction. The extractant subsequently was derivatized in situ with the silylation reagent N,O-bis(trimethylsilyl)trifluoroacetamide with 0.1% trimethylchlorosilane. The product was then adsorbed on a polyacrylate solid-phase microextraction (SPME) fiber in the headspace. Sea sand was used as a dispersive material in the SFE step. The analytical linear ranges for the preservatives and antioxidants were found to be from 10 to 1000 ng g(-1) with RSD values below 7.8%. The detection limits ranged from 0.5 to 8.3 ng g(-1). These results are better than those obtained by using only SPME or SFE for trace preservatives and antioxidants analysis in cosmetic matrices. The new method was successfully utilized to determine the amounts of preservatives and antioxidants in real cosmetics without the need for tedious pretreatments.

Counterfeit homeopathic medicinal products: syrups. A simple and rapid LC-ESI-MS method to detect preservatives not declared in label

A rapid and simple LC-ESI-MS method for the simultaneous detection and quantitation of six preservatives in homeopathic syrups has been developed. Counterfeit homeopathic syrups are suspected to contain preservatives that are not declared in label. For this reason a method to ascertain the absence of sorbic and benzoic acids, methyl-, ethyl-, propyl- and butyl-parabens, as the most frequently utilised preservatives, has been developed. Analytes were eluted with a linear gradient of acetonitrile-5mM ammonium acetate in 12 min using 2,4-dichlorobenzylalchol as Internal Standard. The HPLC separation was performed on an Eclipse XDB-C18 (2.1 mm x 50 mm-5 microm) column and the ESI-MS detection was performed in negative ion mode. Linearity of the method was studied in the range of 2 pg to 10 ng injected and correlation coefficients r2 > or =0.9992 were obtained. LOD ranged from 0.04 to 0.4 ng mL(-1).

Capillary electrophoresis for the analysis of small-molecule pharmaceuticals

This paper reviews the application of CE to the analysis of small-molecule pharmaceuticals. The areas of pharmaceutical analysis covered are enantiomer separation, the analysis of small molecules such as amino acids or drug counter-ions, pharmaceutical assay, determination of related substances and physicochemical measurements such as log P and pK(a) of compounds. The different electrophoretic modes available and their advantages for pharmaceutical analysis are described. Recent applications of CE for each subject area are tabulated with electrolyte details.

Simultaneous analysis of antioxidants and preservatives in cosmetics by supercritical fluid extraction combined with liquid chromatography-mass spectrometry

This study evaluated supercritical fluid extraction (SFE) combined with liquid chromatography-mass spectrometry (LC-MS) to determine trace preservatives and antioxidants including methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol (alpha-t) and alpha-tocopherol acetate (alpha-ta) in cosmetic products. A supercritical fluid extraction procedure was used to isolate four paraben preservatives and four antioxidants from the cosmetic matrix before quantitative analysis. The optimum extraction condition was performed with static extraction for 5 min, then dynamic extraction for 20 min by using carbon dioxide supercritical fluid at 14,000 kPa and 65 degrees C. Methanol was used as collection solvent and the sea sand was chosen as a filling material. The analytes were separated on a C18 reversed-phase column using methanol-water as mobile phase and quantified by measuring its mass spectrometry. The linearity range is from 10 to 20,000 ng/g with RSD values below 18%. Detection limits are achieved at the level of 4.7-142 ng/g. It was successfully applied to the determination of paraben preservatives and antioxidants in cosmetics without tedious pretreatment.