Comparación del desempeño técnico-asistencial en programas escolares con diferentes modalidades de implementación / Comparison of technical-assisstance performance in school programs with different implementation modalities

Se comparó el desempeño técnico-asistencial de 2 programas de atención odontológica con iguales protocolos de atención y diferente modalidad de implementación. Ambos programas se caracterizaron por un perfil preventivo-promocional; uso de protocolos validados según riesgo biológico, atención odontológica adaptada a sedes no convencionales, recursos asignados por método de necesidades; ejecución por recurso humano pre-profesional supervisado y modulación por altas. La modalidad de implementación difirió en la densidad/concentración de las actividades realizadas: en el Programa Extensivo (PE) las acciones se implementaron con frecuencia semanal; en el Programa Intensivo (PI) las acciones se concentraron en una semana en el año. Cobertura anual: PE = 120 escolares de 6 a 9 años de edad; PI = 180 escolares y preescolares de 3 a 12 años de edad. Se midió la cantidad de prestaciones, sesiones y tiempo -en minutos- hasta alcanzar el Alta Básica Operativa (ABO). Para comparar grupos (PI y PE) se utilizaron los tests: U de Mann Whitney, t de Student para mues-tras independientes, chi cuadrado y comparación de proporciones. La razón de prestaciones/sesión fue significativamente mayor (p=0,000) en el programa intensivo. El número de prestaciones hasta el alta (ABO) y la razón tiempo/sesión no mostraron diferencias entre programas (p=0,8 p=0,087), mientras que se evidenció una mayor razón tiempo/prestación y tiempo en alcanzar el alta (ABO) en la modalidad extensiva (p=0,000). La modalidad intensiva mostró mayor eficiencia en el desempeño técnico asistencial que la extensiva (AU)

Aim: To compare technical-care performance of 2 dental care programs with the same care protocols and different implementation modalities. Both programs shared the following features: preventive-promotional profile; use of validated clinical protocols according to biological risk, dental care adapted to non-conventional settings, allocation of resources by needs method; supervised pre-professional human resource and modulation by discharges. The implementation mode differed in the density/concentration of the activities: in the extensive program (EP) the actions were implemented on a weekly basis along the year; in the intensive program (IP) the actions were concentrated in one week in the year. Annual coverage of the programs: 180 schoolchildren and preschoolers (3 -12 years old); EP = 120 schoolchildren (6 - 9 years old). We measured the following variables: the number of dental services performed, the number of sessions and the time, in minutes, to reach the basic operating discharge (BOD). We used the following tests to compare groups (IP and EP): Mann Whitney U; Student's t for independent samples, chi square and comparison of proportions test. The action per session ratio was significantly higher (p=0.000) in the intensive program. The number of actions performed until discharge (BOD) and the time per session ratio did not show differences between programs (p=0.8 p=0.087). In the extensive mode, compared to intensive mode, it took longer to reach discharge (BOD) (p=0.000) The program implemented with intensive modality (PI) showed greater efficiency regarding technical-care performance when compared to the extensive mode (AU)

Feasibility and Safety of Adopting Next-Day Discharge as First-Line Option After Transfemoral Transcatheter Aortic Valve Replacement.

OBJECTIVES: Data on next-day discharge (NDD) after transcatheter aortic valve replacement (TAVR) are limited. This study investigated the feasibility and safety of NDD as a first-line option (the very-early discharge [VED] strategy) compared with the early-discharge (ED) strategy (2-3 days as a first-line option) after TAVR. METHODS: We reviewed 611 consecutive patients who had minimalist TAVR (transfemoral approach under conscious sedation) and no in-hospital mortality; a total of 418 patients underwent ED strategy (since December 2013) and 193 patients underwent VED strategy (as part of a hospital initiative to reduce length of stay, since August 2016). NDD in the VED strategy was performed with heart team consensus in patients without significant complications. The primary outcome was a composite of 30-day all-cause mortality/rehospitalization. RESULTS: Sixty-five patients (33.7%) in the VED strategy and 10 patients (2.4%) in the ED strategy were discharged the next day (P<.001). NDD patients had received balloon-expandable (n = 30) or self-expanding valves (n = 45) and showed a similar primary outcome rate compared with non-NDD patients. After adjustment using propensity score matching (172 pairs), post-TAVR length of stay was significantly shorter in the VED group (3.2 ± 3.1 days) than in the ED group (3.5 ± 2.7 days; P<.01). The primary outcome did not differ between the two groups (7.0% vs 11.6%; P=.14), with comparable 30-day mortality rate (1.2% vs 2.3%; P=.68) and rehospitalization rate (5.8% vs 11.1%; P=.08). CONCLUSIONS: Utilization of NDD as a first-line option after minimalist TAVR is feasible and safe, and leads to further reduction in length of stay compared with an ED strategy.

A New Kinetic Spectrophotometric Method for the Quantitation of Amorolfine.

Amorolfine (AOF) is a compound with fungicide activity based on the dual inhibition of growth of the fungal cell membrane, the biosynthesis and accumulation of sterols, and the reduction of ergosterol. In this work a sensitive kinetic and spectrophotometric method for the AOF quantitation based on the AOF oxidation by means of KMnO4 at 30 min (fixed time), pH alkaline, and ionic strength controlled was developed. Measurements of changes in absorbance at 610 nm were used as criterion of the oxidation progress. In order to maximize the sensitivity, different experimental reaction parameters were carefully studied via factorial screening and optimized by multivariate method. The linearity, intraday, and interday assay precision and accuracy were determined. The absorbance-concentration plot corresponding to tap water spiked samples was rectilinear, over the range of 7.56 × 10-6-3.22 × 10-5 mol L-1, with detection and quantitation limits of 2.49 × 10-6 mol L-1 and 7.56 × 10-6 mol L-1, respectively. The proposed method was successfully validated for the application of the determination of the drug in the spiked tap water samples and the percentage recoveries were 94.0-105.0%. The method is simple and does not require expensive instruments or complicated extraction steps of the reaction product.

Antihypertensive effects of oleuropein-enriched olive leaf extract in spontaneously hypertensive rats.

The effects of chronic consumption of oleuropein-enriched (15% w/w) olive leaf extract (OLE) on blood pressure, endothelial function, and vascular oxidative and inflammatory status in spontaneously hypertensive rats (SHR) were evaluated. Ten Wistar Kyoto rats (WKY) and twenty SHR were randomly assigned to three groups: a control WKY group, a control SHR group and a SHR group treated with OLE (30 mg kg(-1)) for 5 weeks. Long-term administration of OLE reduced systolic blood pressure, heart rate, and cardiac and renal hypertrophy. OLE treatment reversed the impaired aortic endothelium-dependent relaxation to acetylcholine observed in SHR. OLE restored aortic eNOS phosphorylation at Ser-1177 and Thr-495 and increased eNOS activity. OLE eliminated the increased aortic superoxide levels, and reduced the elevated NADPH oxidase activity, as a result of reduced NOX-1 and NOX-2 mRNA levels in SHR. OLE reduced the enhanced vascular TLR4 expression by inhibition of mitogen-activated protein kinase (MAPK) signaling with the subsequent reduction of proinflammatory cytokines. In conclusion, OLE exerts antihypertensive effects on genetic hypertension related to the improvement of vascular function as a result of reduced pro-oxidative and pro-inflammatory status.

Supervivencia y estado de restauraciones con ionómero vítreo en un programa escolar docente-asistencial / Survival and status of glass ionomer restorations at a teaching care school program

Objetivos: describir la supervivencia y estado post-1 año de restauraciones con ionómero vítreo (IV) realizadas por recurso humano preprofesional y analizar la asociación entre el estado de las mismas y variables intervinientes. Métodos: se evaluaron 129 restauraciones (en 54 escolares; edad: 6 y 7 años) con IV (Ketac Molar Easymix), realizadas por estudiantes del último año de la carrera de odontología en un programa escolar con un a técnica sistematizada basada en los criterios de la restauración atraumática. Para la evaluación, cuatro examinadores basaron sus observaciones en el criterio de Franken que establece 7 categorías: 0= presente en buenas condiciones, 1= ligero defecto marginal, 2= ligero desgaste, 3= defecto marginal >0,5 mm, 4= desgaste >0,5 mm, 5= restauración partida o parcialmente perdida y 6= no presente. Para su análisis descriptivo, fueron reagrupadas en 3 categorías en términos de necesidad de reintervención: N1 (0 y 2) no necesita reintervención, N2 (1 y 3) necesita mínima intervención y N3 (4, 5 y 6) requiere reemplazo. Se consideran variables intervinientes: dentición, extensión de la cavidad y presencia de lesiones activas de caries en la cavidad bucal post-1 año clínica. Se calcularon las distribuciones de frecuencia y se estudió asociación con la prueba de Chi cuadrado. Resultados: la tasa de supervivencia post -1 año fue de 94,6 por ciento. El estado de las restauraciones mostró asociación significativa con la presencia de actividad de caries en boca en el momento de la evaluación. Conclusiones: la tasa de supervivencia de las restauraciones con IV post-1 año realizadas por recursos humano preprofesional supervisado, fue alta. La presencia de actividad de caries en boca podría ser una variable del estado de las restauraciones

Determination of Oxytetracycline from Salmon Muscle and Skin by Derivative Spectrophotometry.

A method was developed for the identification and quantification of oxytetracycline residues present in salmon muscle and skin using UV-Vis derivative spectrophotometry. With this method, it was possible to reduce the number of steps in the procedure typically required for instrumental analysis of a sample. The spectral variables, order of the derivative, scale factor, smoothing factor, and analytical wavelength were optimized using standard solutions of oxytetracycline dissolved in 900 mg/L oxalic acid in methanol. The matrix effect was significant; therefore, quantification for oxytetracycline residues was carried out using drug-free salmon muscle and skin samples fortified with oxytetracycline. The LOD and LOQ were found to be 271 and 903 µg/kg, respectively. The precision and accuracy of the method were validated using drug-free salmon muscle and skin tissues fortified at three different concentrations (8, 16, and 32 mg/kg) on 3 different days. The recoveries at all fortified concentrations were between 90 and 105%, and RSDs in all cases were less than 6.5%. This method can be used to screen out compliant samples and thereby reduce the number of suspect positive samples that will require further confirmatory analysis.

Quercetin and its metabolites inhibit the membrane NADPH oxidase activity in vascular smooth muscle cells from normotensive and spontaneously hypertensive rats.

Quercetin, the most abundant dietary flavonol, exerts antioxidant effects reducing vascular superoxide (O2(-)) and improving endothelial function in animal models of cardiovascular disease. Herein we evaluated the effects of quercetin, and its plasma metabolites, on the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activity, the main source of O2(-) in the vessel wall, in vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Quercetin and its metabolites isorhamnetin and kaempferol inhibited the NADPH-stimulated lucigenin-chemiluminescence signal in VSMCs from both strains. The inhibitory effect of quercetin-3-glucuronide increased after prolonged incubation and was inhibited in the presence of the ß-glucuronidase inhibitor saccharolactone. These effects were unrelated to their O2(-) scavenging properties, since they induced only a small inhibition of the rate of pyrogallol autoxidation at high concentrations. All bioflavonoids tested acted as non-competitive inhibitors with respect to NADPH. In conclusion, quercetin and its metabolites inhibit the NADPH oxidase activity in VSMCs reducing O2(-) generation more efficiently than their effect as O2(-) scavengers. The effect of quercetin-3-glucuronide was due to deconjugation and release of free quercetin. The effect is similar in VSMCs from normotensive and hypertensive animals.

Rotating disk sorptive extraction of Cu-bisdiethyldithiocarbamate complex from water and its application to solid phase spectrophotometric quantification.

This study demonstrates the first use of polydimethylsiloxane (PDMS) immobilized on a rotating disk for the extraction of copper from aqueous matrices and its subsequent direct determination by solid phase UV-Visible spectrophotometry. To accomplish the solid-phase extraction and the direct solvent-free spectrophotometric measurement, sodium diethyldithiocarbamate (NaDDTC) was used as an analytical reagent to form the uncharged chromophore complex Cu(DDTC)2, which absorbs at 432 nm. Different physicochemical conditions (pH, temperature, reagent concentration, chemical modifiers) and hydrodynamic factors (rotation velocity, extraction time, sample volume) were optimized. Under the optimized conditions, extraction equilibrium times of 30, 53 and 90 min were obtained for 100, 500 and 1000 mL of sample, respectively, with preconcentration factors of 286, 712 and 1284, respectively. The methodology was precise (repeatability and reproducibility of 7.2 and 8.4%, respectively, as relative standard deviation) and accurate (recovery of 96.7%) when analyzing a multielement certified reference standard. The latter study also confirmed the high selectivity of the extraction and determination of the copper chromophore over other metal ions. The obtained limits of detection and quantification reached values lower than 12 µg L(-1), which can be reduced further by increasing the sample volume. Accuracy was also assessed using both recovery tests on drinking water matrices (95.5% recovery) and comparison with results obtained by an independent method using inductively coupled plasma-optical emission spectroscopy (ICP-OES); no significant differences were observed.

PPARß activation restores the high glucose-induced impairment of insulin signalling in endothelial cells.

BACKGROUND AND PURPOSE: PPARß enhances insulin sensitivity in adipocytes and skeletal muscle cells, but its effects on insulin signalling in endothelial cells are not known. We analysed the effects of the PPARß/δ (PPARß) agonists, GW0742 and L165041, on impaired insulin signalling induced by high glucose in HUVECs and aortic and mesenteric arteries from diabetic rats. EXPERIMENTAL APPROACH: Insulin-stimulated NO production, Akt-Ser(473) and eNOS-Ser(1177) phosphorylation, and reactive oxygen species (ROS) production were studied in HUVECs incubated in low- or high-glucose medium. Insulin-stimulated relaxations and protein phosphorylation in vessels from streptozotocin (STZ)-induced diabetic rats were also analysed. KEY RESULTS: HUVECs incubated in high-glucose medium showed a significant reduction in insulin-stimulated production of NO. High glucose also reduced insulin-induced Akt-Ser(473) and eNOS-Ser(1177) phosphorylation, increased IRS-1-Ser(636) and ERK1/2-Thr(183) -Tyr(185) phosphorylation and increased ROS production. The co-incubation with the PPARß agonists GW0742 or L165041 prevented all these effects induced by high glucose. In turn, the effects induced by the agonists were suppressed when HUVEC were also incubated with the PPARß antagonist GSK0660, the pyruvate dehydrogenase kinase (PDK)4 inhibitor dichloroacetate or after knockdown of both PPARß and PDK4 with siRNA. The ERK1/2 inhibitor PD98059, ROS scavenger catalase, inhibitor of complex II thenoyltrifluoroacetone or uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone, also prevented glucose-induced insulin resistance. In STZ diabetic rats, oral GW0742 also improved insulin signalling and the impaired NO-mediated vascular relaxation. CONCLUSION AND IMPLICATIONS: PPARß activation in vitro and in vivo restores the endothelial function, preserving the insulin-Akt-eNOS pathway impaired by high glucose, at least in part, through PDK4 activation.

Determination of crystal violet in water by direct solid phase spectrophotometry after rotating disk sorptive extraction.

The microextraction of crystal violet (CV) from water samples into polydimethylsiloxane (PDMS) using the rotating disk sorptive extraction (RDSE) technique was performed. The extracting device was a small Teflon disk that had an embedded miniature magnetic stirring bar and a PDMS (560 µL) film attached to one side of the disk using double-sided tape. The extraction involves a preconcentration of CV into the PDMS, where the analyte is then directly quantified using solid phase spectrophotometry at 600 nm. Different chemical and extraction device-related variables were studied to achieve the best sensitivity for the determination. The optimum extraction was performed at pH 14 because under this condition, CV is transformed to the neutral and colorless species carbinol, which can be quantitatively transferred to the PDMS phase. Although the colorless species is the chemical form extracted in the PDMS, an intense violet coloration appeared in the phase because the -OH bond in the carbinol molecule is weakened through the formation of hydrogen bonds with the oxygen atoms of the PDMS, allowing the resonance between the three benzene rings to compensate for the charge deficit on the central carbon atom of the molecule. The accuracy and precision of the method were evaluated in river water samples spiked with 10 and 30 µg L(-1) of CV, yielding a relative standard deviation of 6.2% and 8.4% and a recovery of 98.4% and 99.4%, respectively. The method detection limit was 1.8 µg L(-1) and the limit of quantification was 5.4 µg L(-1), which can be decreased if the sample volume is increased.

Simultaneous determination of albendazole and praziquantel by second derivative spectrophotometry and multivariated calibration methods in veterinary pharmaceutical formulation.

The simultaneous determination of albendazole (ABZ) and praziquantel (PZQ) was performed by different mathematical approaches: second derivative spectrophotometry (SDS), classical least squares, regression of partial least squares and principal components regression based on spectral data of drugs dissolved in methanol-hydrochloric acid solution. The detection limits for multivariate calibrations were determined by creating a surrogate variable signal. SDS presented the best analytical features. The recoveries of ABZ and PZQ from the synthetic samples were near to 100 +/- 5%. The methods were applied in veterinary pharmaceutical formulation whose mass ratio ABZ:PZQ is 10:1; the results obtained were according to nominal content.

UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline.

The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0+/-0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, (1)H NMR, measurement of relaxation times T(1) and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

A new Cu(II)-5-(4-sulphophenylazo)-8-aminoquinoline complex used for copper determination in presence of gold and silver in water and mineral samples.

In this work, a characterization of reagent chromophore 5-(4-sulphophenylazo)-8-aminoquinoline [SPA] by IR and 1H RMN was carried out and a pK(a) value of 3.55+/-0.03 was found as well. An 1:2 stoichiometry for the Cu(II)-SPA complex was determined at pH 9 by Job and molar ratio methods. A value of 1.4 x 10(14) for the stability constant was also found. Based on the formation of this complex a new method for the copper determination in presence of gold and silver was developed by derivative spectrophotometry using a previous preconcentration on solid phase. In this method, the analytical measures were executed directly in the solid phase containing the complex. The Cu(II) reacts with the reagent chromophore SPA previously retained in the anionic exchange DEAE Sephadex A25. In this determination, the first derivative at 605 nm was used. The quantification range was between (3.2+/-0.3 x 10(-1)) x 10(-8) and (94.4+/-0.9) x 10(-8) mol L(-1) (3.2+/-0.3 x 10(-1)) x 10(-8), and (94.4+/-0.9) x 10(-8) mol L(-1). The repeatability expressed as RSD was between 1.1 and 2.0%. The method was applied successfully for the copper determination in mineral residuals and natural water samples. The results were consistent with those provided by ICP-mass spectrometry.

Simultaneous determination of Cu(II) and Ag(I) on SP Sephadex C25 as complexes with 1-phenyl-1,2-propanedione-2-oximethiosemicarbazone by derivative spectrophotometry.

A simple, rapid, and sensitive method has been developed for the simultaneous determination of trace amounts of copper and silver using 1-phenyl-1,2-propanedione-2-oximethiosemicarbazone (PPDOT) as a chromogenic reagent. The proposed method was based on retention and preconcentration of the complexes Cu(III)-PPDOT and Ag(I)-PPDOT on a solid phase in acid medium. The complexes were quantitatively retained in the cation exchanger SP Sephadex C25, and the analytical measurements were executed directly in the solid phase by derivative spectrophotometry. In this simultaneous determination, the second derivative and the zero crossing method were used. The determination of copper and silver was carried out to 321.0 and 427.0 nm, respectively. In order to obtain quantitative recoveries of the metal ions, various experimental analytical parameters, such as pH, stirring time, volume, and amount of solid phase, were optimized. The effect of interfering ions on the determination was described. The recovery values for Cu(II) and Ag(I) were found to be > 98%, and the relative standard deviation was < or = 2%. The detection limits (3sigma criterion) for Cu(II) and Ag(I) were found to be 0.9 x 10(-8) and 13 x 10(-8) M, respectively. The developed method was utilized for preconcentration and determination of Cu(II) and Ag(I) in industrial effluents and natural water samples. The results were consistent with those provided by inductively coupled plasma/mass spectrometry.

Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater.

Chemical, electrochemical and flow variables were optimized to examine the effectiveness of the electrocoagulation process for the removal of copper, lead and cadmium. The electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12 mg dm(-3) of copper, 4 mg dm(-3) of lead and 4 mg dm(-3) of cadmium. The optimum conditions for the process were identified as pH=7, flow rate=6.3 cm(3) min(-1) and a current density between 31 and 54 A m(-2). When the electrode geometric area and time of electrolysis reached critical values, the copper removal reached a maximum value of 80%. A linear relationship was identified between the current density and the mass of generated sludge. In addition, a linear relationship was found between specific energy consumption and current density. The results of this investigation provide important data for the development of an industrial-scale electrolytic reactor.

Chefs' knowledge of coeliac disease (compared to the public): a questionnaire survey from the United Kingdom.

BACKGROUND: For patients with coeliac disease (CD), compliance with a gluten-free diet, when eating food not prepared at home may be difficult. AIMS: We assessed whether there are differences in the eating habits of coeliac patients when compared to the general public. In addition, we compared chefs' knowledge with the public's knowledge about CD. METHOD: A questionnaire survey about CD was performed on coeliac patients, chefs and the general public from the United Kingdom (UK). RESULTS: Three hundred and nineteen coeliac patients [mean age 53.8 years, 65.8% female], 513 members of the public [49.2 years, 62.6% female] and 322 chefs [37.6 years, 15.2% female] were interviewed. Chefs were less likely to have heard of CD when compared to the public (17.1% (55/322) versus 44.2% (227/513), respectively, P<0.0001). Coeliac patients ate less frequently at a friend's house than the general public (P = 0.003). Coeliac patients ate less frequently from take-away establishments (P<0.0001). However, coeliac patients' ate as frequently in restaurants (P = 0.078). CONCLUSIONS: In the UK, chefs appear to know less about CD than the general public. Patients with CD feel justifiably cautious when eating food not prepared at home. Educating chefs about a gluten-free diet may alleviate the social restrictions on coeliac patients.

Arsenic speciation in water samples containing high levels of copper: removal of copper interference affecting arsine generation by continuous flow solid phase chelation.

A simple continuous flow method is proposed to eliminate copper interference in arsenic speciation by hydride generation, based on the selective retention of this interfering ion in an iminodiacetate chelating resin previous to the hydride generation process. The arsines generated were cold trapped and measured by ICP/OES. The proposed method allows about 98% of the copper present in the samples to be removed. Minor co-retention of As(V) was observed as a result of electrostatic interaction between the arsenate anion and the nitrogen of the iminodiacetate group of the chelating resin Muromac A-1, the charge distribution of which is modified when copper is chelated. The species As(III), MMA and DMA were not retained in the microcolumn, probably because these species are mainly in the molecular form at the working pH value (4.5). In synthetic samples containing 50 microg l(-1) of each arsenic species together with 100 mg l(-1) copper, the recoveries obtained were: As(V) 97.6%, As(III) 100%, MMA 99.8%, and DMA 99.9%. The method was applied to arsenic speciation in river water samples containing high levels of copper.

Determination of attapulgite and nifuroxazide in pharmaceutical formulations by sequential digital derivative spectrophotometry.

A new method for the sequential determination of attapulgite and nifuroxazide in pharmaceutical formulations by first- and second-derivative spectrophotometry, respectively, has been developed. In order to obtain the optimal conditions for nifuroxazide stability, studies of solvent, light, and temperature effects were performed. The results show that a previous hydrolysis of 2 h in 1.0 x 10(-1)M NaOH solution is necessary in order to obtain stable compounds for analytical purposes. Subsequently, the first- and second-derivative spectra were evaluated directly in the same samples. The sequential determination of the drugs can be performed using the zero-crossing method; the attapulgite determination was carried out using the first derivative at 278.0 nm and the nifuroxazide determination, using the second derivative at 282.0 nm. The determination ranges were 5.7 x 10(-6)-1.0 x 10(-4) and 3.7 x 10(-8) -1.2 x 10(-4)M for attapulgite and nifuroxazide, respectively. Repeatability (relative standard deviation) values of 1.2 and 3.0% were observed for attapulgite and nifuroxazide, respectively. The ingredients commonly found in commercial pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in tablets. Further, infrared spectroscopy and cyclic voltammetry studies were carried out in order to obtain knowledge of the decomposition products of nifuroxazide.

Simultaneous determination of dapsone and pyrimethamine by derivative spectrophotometry in pharmaceutical formulations.

A simple and fast method was developed for the simultaneous determination of dapsone and pyrimethamine by first-order digital derivative spectrophotometry. Acetonitrile was used as a solvent to extract the drugs from the pharmaceutical formulations, and the samples were subsequently evaluated directly by digital derivative spectrophotometry. The simultaneous determination of both drugs was performed by the zero-crossing method at 249.4 and 231.4 nm for dapsone and pyrimethamine, respectively. The best signal-to-noise ratio was obtained when the first derivative of the spectrum was used. The linear range of determination for the drugs was from 6.6 x 10(-7) to 2.0 x 10(-4) and from 2.5 x 10(-6) to 2.0 x 10(-4) mol/L for dapsone and pyrimethamine, respectively. The excipients of commercial pharmaceutical formulations did not interfere in the analysis. Chemical and spectral variables were optimized for determination of both analytes. A good level of repeatability, 0.6 and 1.7% for dapsone and pyrimethamine, respectively, was observed. The proposed method was applied for the simultaneous determination of both drugs in pharmaceutical formulations.

Simultaneous determination of amiloride and furosemide in pharmaceutical formulations by first digital derivative spectrophotometry.

This work presents a simple and fast method for the simultaneous determination of amiloride and furosemide by digital derivative spectrophotometry. HCl 1 x 10(-2) mol/l dissolved in ethanol was used as solvent and to extract drugs from formulations. Subsequently the samples were evaluated directly by first digital derivative spectrophotometry, using a smoothing factor of 8 and scale factor of 1 x 10(-4). The simultaneous determination of furosemide and amiloride can be carried out at 241.4 and 343.6 nm, respectively. In both cases, the zero crossing approach was used. When both compounds are present together in a sample, it is possible to quantify one in the presence of the other, without mutual interference. The determination range was found to be of 6.9 x 10(-8) to 16 x 10(-5) and 6.8 x 10(-8) to 8 x 10(-5) mol/l, for amiloride and furosemide, respectively. A good level of repeatability (RSD) of 0.9 and 0.6% was observed for amiloride and furosemide, respectively. The ingredients commonly found in commercial pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations.