243 research outputs found
Analisi di imminostilbeni (carbamazepina e oxcarbazepina) e metaboliti in fluidi biologici mediante HPLC-DAD
No full textDetermination of l-dopa, carbidopa, 3-O-methyldopa and entacapone in human plasma by HPLC-ED
No full textThe aim of the study was the development of analytical methods suitable for the quantification of ldopa,carbidopa and entacapone in plasma of Parkinsonian patients treated with Stalevo®. The metabolite3-O-methyldopa was also determined to obtain some indications on the pharmacokinetics of l-dopa.For the simultaneous analysis of l-dopa, 3-O-methyldopa and carbidopa, a RP C18 column as the stationaryphase and a mixture of methanol and a pH 2.88 phosphate buffer (8:92, v/v) as the mobile phasewere used. A feasible plasma pre-treatment based on protein precipitation was implemented, obtainingextraction yield higher than 94% for all the analytes. For the analysis of entacapone a RP C8 column anda mixture of methanol, acetonitrile and a pH 1.90 phosphate buffer as the mobile phase (17.5:22.5:60,v/v/v) were used. A plasma pre-treatment procedure was developed, based on solid phase extraction ofentacapone using Oasis HLB cartridges. Extraction yields were good, being always higher than 96%.Both methods, based on HPLC–ED (V = +0.8 V), have been fully validated. Good linearity was obtainedover the following concentration ranges: 100–4000 ngmL−1 for l-dopa, 200–10,000 ngmL−1 for 3-Omethyldopa,25–4000 ngmL−1 for carbidopa and 20–4000 ngmL−1 for entacapone. Precision data weresatisfactory, being R.S.D.% values lower than 5.64%; accuracy also resulted very good with recovery datahigher than 90%. The proposed methods have been successfully applied to the analysis of patient plasmasamples and seem to be suitable for therapeutic drug monitoring purposes
Rapid HPLC analysis of the antiepileptic lamotrigine and its metabolites in human plasma
No full textRapid HPLC analysis of the antiepileptic lamotrigine and its metabolites in human plasma
No full textA liquid chromatographic method with diode array detection (DAD) has been developed for the analysis of the antiepileptic agent lamotrigine (LTG) and its metabolites, lamotrigine 2-N-glucuronide and 2-N-methylated in plasma samples. The analytes were separated on a C8 RP column, using a mobile phase composed of methanol and a 0.45 mM, pH 3.5 phosphate buffer containing 0.17% triethylamine (24:76 v/v). Melatonin was used as the internal standard (IS). The DAD detector was set at 220 nm for the detection of all the analytes. A simple protein precipitation with methanol guaranteed high extraction yield values (>90%) and good purification from matrix interference. Good linearity was obtained in the 0.1-15.0 microg/mL range for LTG and lamotrigine 2-N-glucuronide and in the 0.1-2.0 microg/mL range for lamotrigine 2-N-methylated. The analytical method was validated in terms of precision, extraction yield, and accuracy. These assays gave RSD% values for precision always lower than 4.3% and mean accuracy higher than 80%. The method seems to be suitable for the analysis of plasma samples from patients treated with Lamicta
A functional food ingredient to promote good health: soy isoflavones. Friends or foes?
No full textSoy products are gaining interest in the health food industry, because of the increasing scientific findings proving their beneficial effects. Soy contains high amounts of proteins and lipids and many bioactive compounds like phytosterols and phytoestrogens. In particular, scientific research focuses on the last category that contains isoflavones naturally present in soy and soy foods. Many of the health benefits of soy are derived from its main isoflavones, genistein and daidzein. Despite the beneficial effects of isoflavones on health are still controversial, some epidemiological studies suggest that the consumption of soy products could play a role in the prevention of several cancers, menopausal symptoms, coronary heart disease and osteoporosis. Consequently, the industry is increasingly developing products that offer an alternative to traditional soy foods like tofu or soy milk, and precisely isoflavone concentrates and extracts for dietary supplements and new functional foods designed to provide health benefits for the consumer. In order to verify the content of the bioactive compounds of the main isoflavones (and their glicosides) in soy foods and derived dietary supplements, some analytical methods have been developed in our Laboratory of Pharmaco-Toxicological Analysis. Firstly, a capillary electrophoresis technique was selected for its high efficiency to separate numerous compounds in these complex food matrices. The development of a second method based on the use of HPLC in reversed phase mode is in progress
Output growth volatility and remittances
No full textSince output growth volatility has negative effects on growth, poverty and welfare, especially in poorer countries, it is crucial to identify the country-specific factors that affect it. The empirical literature has focused mostly on financial development, policy distortions and globalization variables. Among the latter, attention has been directed in particular to trade and financial openness. We contribute to this literature by adding what we see as the missing globalization variable, the one related to the increasingly important phenomenon of international migrations, namely emigrants' remittances. Remittances can help reduce output growth volatility thanks to their considerable magnitude, stability and low pro-cyclicality. Applying an empirical framework taken from the existing literature to a sample of about 60 emerging and developing economies over the period 1980-2003, we provide robust evidence that remittances are negatively correlated to output growth volatility. Instrumental variable estimation supports our intuition about the direction of causality.output growth volatility, workers’ remittances, compensation of employees, financial development, trade and financial openness
Comparison of analytical methods for the quality control of a new formulation containing soy extract and melatonin
No full textThree analytical methods have been developed and compared for the quality control of a new formulation (Soymen GN® capsules) containing soy extract and melatonin for the treatment of menopausal symptoms. The first method is based on micellar electrokinetic chromatography (MEKC) with diode-array detection, using a mixture of basic carbonate buffer (95%) and methanol (5%), containing 55 mM SDS, as the background electrolyte. The second method is a high-performance liquid chromatographic (HPLC) method with ultraviolet detection at 260 nm. The third method is an HPLC method coupled to amperometric detection which is carried out at an oxidation potential of + 0.8 V. In both HPLC systems, the chromatographic separation is obtained on a reversed-phase C18 column using a mixture of acetonitrile and an acidic phosphate buffer (25/75, v/v) as the mobile phase. A feasible pre-treatment procedure with a methanol/water mixture has been implemented to achieve the quantitative extraction of the main soy isoflavones and of melatonin from the capsules. The results obtained with the three methods are in good agreement with each other and satisfactory in terms of linearity (r2 > 0.9996), precision (RSD 97%). Thus, each of the three analytical methods seems to be suitable for the simultaneous analysis of the main soy isoflavones and melatonin in the new commercial formulation
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