Biography
Abstract
Bronopol (2-bromo-2-nitropropane-1,3-diol) is an effective preservative employed in cosmetic formulations. However, under specific conditions, bronopol can decompose releasing low levels of formaldehyde and nitrites . These last compounds can react with any secondary amines or amides to produce significant levels of carcinogenic nitrosamines. The production of nitrosamines in cosmetic products has to be avoided. For this reason, although the use of bronopol is authorized in the current European Regulation, the maximum allowed concentration of bronopol in cosmetic products is 0.1%. Nevertheless, there is still no official method of analysis for the determination of this compound. The aim of this work is to propose a fast and simple analytical method to determine bronopol in cosmetic products. The proposed method is based on a vortex-assisted emulsification extraction, as one-step solution extraction process to prepare cosmetic samples, followed by liquid chromatography with spectrophotometric detection at 250 nm. The best results were achieved by using a C18 column at the following optimized conditions: Temperature, 40ºC; Flow rate, 0.5 mL min-1; Mobile phase, ethanol and a 1% acetic acid aqueous solution were used to perform the separation by elution gradient. Satisfactory results were obtained for the analysis of 19 cosmetic samples including creams, shampoos and bath gels, with good recoveries and repeatability. Limits of detection and quantification were at the low Bg mL−1 levels. These good analytical features, as well as its environmentally-friendly characteristics, make the presented method suitable for the determination of bronopol in cosmetic products.
Biography
Asmaa El-Zaher has completed her PhD at Cairo University in 1999 and teaches pharmaceutical and medicinal chemistry in Cairo, Ain Shams, Misr International Universities in Egypt and Umm Al-Qura University in Saudi Arabia. She is specialized in drug analysis. She supervised more than 12 master and PhD awarded thesis and about the same number in progress. She has been awarded for her international publication for more than 4 times by Cairo University. She has published more than 25 papers in reputed journals and more than 10 conference abstracts. She has been serving as reviewer for many reputable journals.
Abstract
A rapid, precise and selective RPLC method was developed for the simultaneous determination of the widely used oral anti-diabetic; metformin hydrochloride (MTF), along with some of the most commonly prescribed oral anti-diabetic medications representing different pharmacological classes, namely; sitagliptin phosphate (SIT), pioglitazone hydrochloride (PGZ), gliclazide (GLZ), glibenclamide (GLB) and repaglinide (RPG), in bulk, laboratory prepared mixtures and their pharmaceutical formulations. The developed method is recommended for application in the quality control of the herbal anti-diabetic products to detect possible counterfeits. The chromatographic separation carried out using gradient elution mode with acetonitrile: 0.05 M potassium di hydrogen phosphate (MKP) and 0.01 M sodium octane sulphonate (SOS) (pH 3.55) at a flow rate of 0.85 ml/min on a Kromasil 100- C18, (30 x 0.4 cm, 10 µm) at a temperature of 40°C. UV detection carried out at 220 nm. The method validated according to ICH guidelines. Linearity, accuracy and precision were satisfactory over the concentration ranges of 0.05-205 µg/ml for MTF, at 0.05-100 µg/ml for PGZ, GLB and SIT, at 0.1-100 µg/ml for RPG and at 1-100 µg/ml for GLZ. The correlation coefficients were > 0.99 for all analytes. Limits of quantification (LOQs) found to be 0.002, 0.003, 0.009, 0.012, 0.007 and 0.024 µg/mL for MTF, SIT, PGZ, GLZ, GLB and RPG respectively. The method was successfully applied for the determination of each of the studied drugs in their synthetic mixtures and pharmaceutical dosage forms. The developed method is specific and accurate for the quality control and routine analysis of the cited drugs in their pharmaceutical preparations