Biomedical subjects

C N Carducci

Publications and source records attributed to C N Carducci.

At least 19 recordsLinked to original sources

PubMed2005

A link between lead and cadmium kinetic speciation in seawater and accumulation by the green alga Ulva lactuca.

In this work, studies on the bioaccumulation of Cd and Pb by Ulva lactuca at different sites of Gulf San Jorge (Patagonia, Argentina) are presented. Higher values of bioaccumulated Cd were found in Punta Maqueda - a site believed to serve as a control - in comparison to those in Punta Borja, a place highly exposed to urban and industrial activities. Consequently; the labile fractions of Cd and Pb in seawater were determined with a flow injection-preconcentration manifold interfaced to a graphite furnace-atomic absorption spectrometer (FI-GFAAS). The results obtained by kinetic speciation showed that the variable that correctly explains heavy metals accumulation in the alga, is the labile metal fraction in seawater. We propose to use an enhancement ratio - on the basis of the kinetically labile metal fraction - for calculation of the metal accumulated by the alga relative to its environment.

Argentina↗

PubMed2003

Simultaneous determination of free and conjugated bile acids in serum by cyclodextrin-modified micellar electrokinetic chromatography.

A simultaneous determination of 15 free and most conjugated forms of bile acids (BA) in serum using capillary electrophoresis is described. The optimized and validated method proposed in this work is straightforward and rapid, employing affordable equipment. A background electrolyte of 5 mM beta-cyclodextrin, 5 mM 2-hydroxypropyl-beta-cyclodextrin, 50 mM SDS and sodium borate-dihydrogen phosphate pH 7.0 with 10% of acetonitrile was used. The complete separation of 15 BA, not easily achievable with other methods, is performed in less than 12 min using a UV detector with good precision and accuracy. BA were extracted from pretreated serum samples using a C(18)-solid-phase extraction and the recovery values ranged from 65 to 107.8%. Limits of quantitation were between 0.58 and 3.2 microM. This method proved to be suitable to determine individual BA profiles which are more useful than total serum bile acids as indicators of metabolic disorders and hepatobiliary diseases.

Bile Acids and Salts↗

PubMed2001

Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

Bile Acids and Salts↗

PubMed2000

Determination of bile acids in pharmaceutical formulations using micellar electrokinetic chromatography.

A micellar electrokinetic chromatography method (MEKC) has been developed and validated for the determination of bile acids (BA) such as ursodeoxycholic acid (UDCA), dehydrocholic acid (DHCA) and deoxycholic acid (DCA) in pharmaceuticals for quality control purpose. The background electrolyte consisted of 20 mM borate-phosphate buffer containing 50 mM sodium dodecylsulfate (SDS), and acetonitrile as additive. UV detection was set at 185 nm. Selectivity, linearity, range, repeatability, intermediate precision and accuracy showed good results. Comparison of the values obtained by MEKC and HPLC methods were in close agreement.

Bile Acids and Salts↗

PubMed2000

Analysis of cis-trans isomers and enantiomers of sertraline by cyclodextrin-modified micellar electrokinetic chromatography.

In this work development, optimization and validation of a cyclodextrin-modified micellar electrokinetic chromatography (CD-modified MEKC) method is proposed to resolve separation of the sertraline hydrochloride and synthesis-related substances. Sertraline hydrochloride, the cis-(1S,4S) enantiomer form, is used as an antidepressant therapeutic agent. A buffer concentration composed of 20 mM sodium borate, pH 9.0 with 50 mM sodium cholate, 15 mM sulfated beta-cyclodextrin and 5 mM hydroxypropyl-beta-cyclodextrin was found to be the most suitable background electrolyte. Quantitation of the impurities at levels of 0.1% in different samples of the bulk drug was determined. A comparison of the results with those obtained by HPLC methodology was also accomplished. The method proved appropriate for testing the purity of sertraline hydrochloride in bulk drug.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed1999

Capillary electrophoretic method for quality control of phospholipid products.

A practical, low cost capillary electrophoretic method for phospholipid products employed in pharmaceutical, cosmetic and food industries with quality control purposes is described. The phospholipid components of the samples were hydrolyzed prior to their electrophoretic separation. The carrier electrolyte to determine choline, ethanolamine and serine consisted of 5 mM imidazole, pH 3.0 using indirect UV detection at 214 nm. Inositol was quantified employing a buffer of 40 mM sodium borate, pH 10.0 at 40 degrees C and detection at 185 nm. Analytical parameters were evaluated and the results obtained of phospholipid composition in commercial samples from soybeans and animal sources showed acceptable values.

Electrophoresis, Capillary↗

PubMed1999

Fecal bile acid excretion profile in gallstone patients.

Epidemiological studies have shown a positive association between cholesterol gallstones and colonic cancer. These two diseases may be somehow related with bile acids metabolic alterations. The aim of this study was to evaluate the profiles of fecal bile acid in gallstone patients, in order to estimate the quality and amount of fecal bile acids. A fecal bile acid profile of ten gallstone patients and ten controls was compared using high performance liquid chromatography. Total fecal bile acid excretion was significantly increased in gallstone patients compared with controls (692.7 mg/day (302.5-846.2) vs 165.7 mg/day (138.7-221.3), p < 0.01) as was the excretion of secondary free bile acids 562.9 mg/day (253.3-704.9) vs 99.9 mg/day (88.9-154.2), p < 0.01). Lithocholic and glycodeoxycholic acid percentages have also been found to show differences with controls of 55.4 (47.4-73.9) vs 24.6 (22.1-38.4) (p < 0.01) and 29.4 (3.3-41.7) vs 2.8 (1.0-3.8) (p < 0.03), respectively but deoxycholic acid has not shown differences between the two groups. Moreover, the percentage of ursodeoxycholic acid diminished significantly in gallstone patients (1.5 (1.0-2.8) vs 8.6 (6.0-10.39) (p < 0.001), and the decrease of chenodeoxycholic acid was also significant (20.0 (11.4-23.6) vs 8.9 (3.1-10.9) (p < 0.03) along with a rise in the ratios lithocholic/deoxycholic acids (1.8 (1.4-6.4) vs 0.9 (0.6-1.6) (p < 0.05) and glycine/taurine of deoxycholic acid (7.3 (4.1-46.6) vs 0.2 (0.1-0.5) (p < 0.01). In conclusion, we have observed a significant increase of total and secondary fecal bile acid excretion as well as a rise of LCA and GDCA percentages and a rise in the ratios of LCA/DCA and glycinet/taurine of DCA.

Adult↗

PubMed1996

Application of extraction disks in dissolution tests of clenbuterol and levothyroxine tablets by capillary electrophoresis.

Sample preparation procedures using octadecyl (C18) extraction disks were developed to obtain accurate and reproducible results for determinations of clenbuterol(20 micrograms per dose) and levothyroxine (100 micrograms per dose) in dissolution media of solid oral dosage forms. Preconcentration of samples allowed final concentrations of 1.1 micrograms/ml of clenbuterol and 4.0 micrograms/ml of levothyroxine to be reached prior to CE analysis. The results obtained by CE were in good agreement with those of HPLC. The precision of the migration time, peak area, peak height and accuracy were determined in both intra-day (n = 6) and inter-day (n = 18) assays. Linearity was demonstrated over the ranges 0.5-80.0 micrograms/ml of clenbuterol and 1.0-30.0 micrograms/ml of levothyroxine. The mean recoveries were higher than 94.0%, ranging from 50 to 125% levels with respect to dose potencies. The proposed methodology may be generally applied to determine drugs at ng/ml concentrations.

Chemistry, Pharmaceutical↗

PubMed1996

Determination of noscapine, hexylresorcinol and anethole in cough lozenges by liquid chromatography.

A liquid chromatographic method was developed for the simultaneous separation and determination of noscapine hydrochloride, hexylresorcinol and anethole in cough lozenges. Analysis was performed on a phenyl column with phosphate buffer- acetonitrile as mobile phase and the separated components were detected at 282 mm. Recoveries obtained for the analytes were of 94.6% for noscapine hydrochloride, 99.1% for hexylresorcinol and 96.3% for anethole. The values of the relative standard deviation were 0.8% for noscapine hydrochloride, 1.5% for hexylresorcinol and 1.1% for anethole. The analytical method was validated and a system suitability test was accomplished for the chromatographic method.

Anethole Trithione↗

PubMed1995

A survey of some trace elements in seaweeds from Patagonia, Argentina.

Cadmium and lead concentrations were determined in some common algal species living in the southernmost coasts of Argentina. Two different sampling areas were chosen: Gulf Nuevo, a locality being influenced by a developing industrial city, and Bay Camarones, a traditional harvest area for seaweed exploitation. Selected species of the genera Lessonia, Macrocystis and Gigartina, all of commercial interest, were collected from the harvest area, and analyses showed low levels of the metals in these species. Accumulation of Pb and Cd was also evident in other common brown seaweeds from the industrial site. Analysis of Al was included in this study due to an aluminum works near one of the sampling sites. High values of this metal ranging between 300 and 3000 mg Al/kg (dry basis) were recorded in the industrialized area. Amongst all of the species studied, Colpomenia sinuosa from Gulf Nuevo exhibited the highest values of aluminum. This preliminary survey showed that, except for Al, the levels of Cd and Pb were lower than those reported in same species of seaweeds from the polluted marine waters of the rest of the world.

Journal Article↗

PubMed1989

Atomic absorption spectrometric determination of inorganic and organic arsenic in some marine benthic algae of the southern atlantic coasts.

Arsenic in the inorganic and organic forms was analyzed in species of marine macro-algae growing in the South Atlantic Ocean. Species of the genera Lessonia, Gigartina, Adenocystis, Leathesia and Colpomenia were investigated. Arsenic accumulation was found in all species studied. Total As content ranged from 5.3 to 56.9 microg As g(-1) and the levels of the inorganic forms ranged from 0.2 to 2.0 microg As g(-1). The complete analytical procedure was validated against a standard reference material (NBS, SRM 1572, citrus leaves) and the value obtained was in good agreement with the certified value. Some commercial seaweed products were also analyzed.

Journal Article↗

PubMed1985