L. Gagliardi

Anti-inflammatory, analgesic and antipyretic 4,6-disubstituted 3-cyano-2-aminopyridines

Abstract 4,6-diaryl and 4,6-aryl-indolyl substituted 3-cyano-2-aminopyridines were synthesized and submitted to evaluation for their anti-inflammatory, analgesic and antipyretic activity. The electronegativity of the substituents and their displacement on the 4- or 6-aryl ring of the 4,6-diaryl-3-cyano-2-aminopyridine nucleus ( 3a – q ) influenced the anti-inflammatory activity which was higher in the presence of electron-realising groups. The introduction of the indol-3-yl substituent in the 4-position of the 3-cyano-2-aminopyridine nucleus ( 6a – x ) increased the anti-inflammatory and analgesic power, but there was no evidence of the relationship among the electronic characteristic of the substituents, their displacement on the 6-phenyl ring and the activity. Conversely, the displacement of the 2-hydroxyphenyl group in the 4-position ( 4a – e ) and of the indol-3-yl group in the 6-position ( 8h – w ) decreased the anti-inflammatory activity. All derivatives did not show any significative antipyretic activity.

High performance liquid chromatography-diode array and electrospray-mass spectrometry analysis of vardenafil, sildenafil, tadalafil, testosterone and local anesthetics in cosmetic creams sold on the Internet web sites

A simple high-performance liquid chromatography (HPLC) method with ultraviolet diode array (UV-DAD) and electrospray ionisation mass spectrometry (ESI-MS) detection has been developed for the determination of vardenafil, sildenafil, tadalafil, testosterone, procaine, lidocaine, prilocaine, and benzocaine in cosmetic creams sold as promising remedies for male erectile dysfunction and female genitals stimulation. The presence of these substances in commercial cosmetic samples is prohibited. Aliquots (1 g) of the cosmetic creams under investigation were diluted 1:100 in methanol, subjected to ultrasonic treatment, added with benzoic acid as internal standard, and analyzed by HPLC-DAD and HPLC-ESI-MS after a further 1:1000 dilution. The compounds were separated by reversed phase chromatography with water (0.02% trifluoroacetic acid) and acetonitrile gradient elution and detected by UV-DAD at 228, 255 and 290 nm and by ESI-MS positive ionisation mode. Benzoic acid was used as internal standard. Linearity was studied with UV-DAD detection from 2.5-7.8 to 250 microg/g range, depending on the different compounds and with ESI-MS in the 3.3-8.9 to 250 ng/g range. Good determination coefficients (r(2) > or = 0.99) were found in both UV-DAD and ESI-MS. Limits of quantifications ranged between 2.5 and 7.8 microg/g for HPLC-UV-DAD assay and between 3.3 and 8.9 ng/g for HPLC-ESI-MS assay depending on different analyzed substances. At three concentrations spanning the linear dynamic ranges of both UV-DAD and ESI-MS assay, mean recoveries were always higher than 90% for the different analytes and intra-assay and inter-assay precision always better than 15% and 12%. This method was successfully applied to the analysis of substances under investigations present in cosmetic creams, freely sold on the Internet web-sites.

Development of a tandem thin-layer chromatography–high-performance liquid chromatography method for the identification and determination of corticosteroids in cosmetic products

Abstract A solid-phase extraction clean-up and and a liquid chromatographic method with ultraviolet detection were developed for the analysis of 51 corticosteroids in cosmetic samples in order to screen commercial samples for the presence of undeclared synthetic corticosteroids. A thin-layer chromatographic analysis was carried out on silica gel plates, using different eluants and detection reagents. When such a preliminary chromatographic separation gave some indications about the presence of steroid compounds, the methanol extracts from real samples were applied to a solid-phase extraction C 18 cartridge, and the analytes eluted with ethyl ether. The high-performance liquid chromatographic separation was then carried out for the identification and determination of the analytes using a Purospher RP-18 column, an isocratic or a gradient elution with a mixture acetonitrile–water and a photodiode-array detector. The accuracy of the method was determined by spiking experiments on home-made cosmetic samples. The analytical recoveries were satisfactory.

High-performance liquid chromatography–diode array and electrospray-mass spectrometry analysis of non-allowed substances in cosmetic products for preventing hair loss and other hormone-dependent skin diseases

A simple high-performance liquid chromatography (HPLC) method with ultraviolet diode array (UV-DAD) and electrospray ionisation mass spectrometry (ESI-MS) detection has been developed for the determination of minoxidil, progesterone, estrone, spironolactone, canrenone, hydrocortisone and triamcinolone acetonide in cosmetic products. The presence of these substances in commercial cosmetic samples is prohibited. The compounds were separated by reversed phase chromatography with water (0.1% trifluoroacetic acid) and acetonitrile gradient elution and detected by UV-DAD at 230, 254 and 280 nm and by ESI-MS positive ionisation mode. Benzoic acid was used as internal standard. Linearity was studied with UV-DAD detection from 1.50 to 1,000 microg/ml or mug/g range, depending on the different compounds and type of cosmetic preparation and with ESI-MS in the 50-1,000 ng/ml or ng/g range. Good determination coefficients (r(2)>or=0.99) were found in both UV and ESI-MS. At three concentrations spanning the linear dynamic ranges of both UV-DAD and ESI-MS assay, mean recoveries were always higher than 90% for the different analytes. This method was successfully applied to the analysis of substances under investigations illegally added in cosmetic cream and lotions, sold on internet web sites to prevent hair loss and other hormone-dependent skin diseases, like acne and hirsutism.

Identification of cosmetic dyes by ion-pair reversed-phase high-performance liquid chromatography

A method based on ion-pair reversed-phase high-performance liquid chromatography with detection at four wavelengths between 400 and 600 nm is reported for the separation and identification of the most common synthetic colour additives in cosmetic products. All the dyes generally employed in the U.S.A. and almost all those in current use in cosmetics in the European Community have been taken into account. The chromatography was performed on a C8 bonded silica packed column, with a 60-min gradient changing from 10 to 95% acetonitrile in water containing 10(-2) M sodium perchlorate (pH 3.0) as mobile phase (flow-rate 2.5 ml/min). Detection limits are in the range 20-100 ng for all dyes investigated. The method has been applied to the analysis of commercial lipsticks.

Simultaneous determination of triprolidine, pseudoephedrine, paracetamol and dextromethorphan by HPLC

SummaryA simple, rapid and specific HPLC method has been developed for the determination of triprolidine, pseudoephedrine, paracetamol and dextromethorphan, in combination, in different pharmaceutical dosage forms, using a reversed-phase C18 column, gradient elution, and UV detection at 254 and 280 nm. No preliminary extraction procedure is required for liquid formulations and a very simple extraction procedure is required for tablets and creams. The recovery of the drugs ranged from 96.0 to 98.7%. The assay results obtained for eight commercially available formulations were in agreement with the amounts declared. The linearity and precision of the method have been assessed.

Determination of sun-screen agents in cosmetic products by reversed-phase high-performance liquid chromatography

As part of a study concerning the determination by high-performance liquid chromatography (HPLC) of sun-screen agents in cosmetics in order to verify their adherence to legislation within the European Economic Community (EEC), we have extended our investigation to a series of compounds commonly employed in suntan preparations as UV absorbers. We report the results of an analysis performed on 85 samples of commercial suntan cosmetics

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

We have developed a reversed-phase HPLC method that allows the complete separation of 22 preservatives, including triclosan and triclocarban, with optimization of the mobile phase composition

Simultaneous Determination of Antioxidants and Preservatives in Cosmetics and Pharmaceutical Preparations by Reversed-Phase HPLC

A high performance liquid chromatographic method for the simultaneous determination of multiple additives in o/w cosmetic and pharmaceutical formulations was developed by using a RP-8 Select B column, a linear gradient elution and UV detection. A very simple extraction procedure was required. The separation obtained for nine antioxidants and seven preservatives was very good under the chromatographic conditions used. Their analysis was carried out in commercial samples and satisfactory results were obtained both for the recovery and the coefficient of variation.

HPLC determination of rhodamine B (C.I. 45170) in cosmetic products

SummaryA method is proposed for the extraction, separation, identification and quantitative measurement of rhodamine B in cosmetics samples The colour is extracted with a solution of orthophosphoric acid in either water or DMF (depending on the type of cosmetic) adsorbed on a polyamide column, and then eluted with water and methanol. Further clean-up of the extract is performed by means of a Bond Elut C-18 cartridge, from which rhodamine B is eluted with methanol-water (8∶2). The final eluate is examined by HPLC. Chromatography is performed on a C-18 column with a gradient elution from 50∶50 to 70∶30 of acetonitrile-water, containing 0.1 M sodium perchlorate, in 15 min. A diodearray detector enables peak purity analysis. The method gives recovery values of approximately 90%, or better, and the reproducibility is within 4%.