Ana Bergold | Universidade Federal do Rio Grande do Sul (original) (raw)

Papers by Ana Bergold

The Open Antimicrobial Agents Journal, 2010

The stability of the broad-spectrum antibiotic ceftiofur was studied in order to investigate the ... more The stability of the broad-spectrum antibiotic ceftiofur was studied in order to investigate the kinetics of pho- todegradation of this drug, using a stability-indicating liquid chromatography (LC) method. The degradation was carried out in aqueous solutions, prepared from reference substance and two pharmaceutical products (Excenel ® and Topcef ® ) containing sodium ceftiofur powder for injection, in quartz cells under UVC ( 254 nm) and UVA light (352 nm). The kinetics parameters of reaction order and the rate constants of the degradation were determined for both products. The degradation process of sodium ceftiofur in solution can be described by first-order kinetics under the experimental conditions used in this study. The obtained results show that the LC method is satisfactory in the determination of the kinetics of degradation of sodium ceftiofur in the presence of its photolytic degradation products. The present study reveals the photolability of the drug. Thus, appropriate l...

Journal of AOAC International, 2007

Ceftiofur sodium is a third-generation broad-spectrum cephalosporin antibiotic, formulated as an ... more Ceftiofur sodium is a third-generation broad-spectrum cephalosporin antibiotic, formulated as an intramuscular injection, that is approved for use in pigs, cattle, poultry, and dogs. The present work reports a method to quantify ceftiofur in powder for injection by comparing the cylinder plate assay and the liquid chromatographic (LC) method. The assay is based on the inhibitory effect of ceftiofur upon the strain of Micrococcus luteus ATCC 10240 used as the test microorganism. Ceftiofur sodium at concentrations ranging from 2.0 to 8.0 microg/mL can be measured in powder for injection. A prospective validation showed that the method is linear (r2 = 0.9998), with precise relative standard deviation (RSD) of 0.8% for product A (Excenel; Pharmacia and Upjohn Co., Kalamazoo, MI) and of 0.6% for product B (Topcef; Eurofarma Lab. Ltda, São Paulo, Brazil), with intermediate precision; between-day RSD = 1.0 and 1.1%, between-analyst RSD = 0.8 and 0.8% for products A and B, respectively and ...

This paper describes the validation of an isocratic HPLC method for the assay of losartan potassi... more This paper describes the validation of an isocratic HPLC method for the assay of losartan potassium tablets and capsules and the evaluation of the stability of drug substance after stress tests by photodiode array detection. The method employ a Shimadzu CLC-C8 column with triethylamine solution (0.5%) pH 2.4 and acetonitrile 60:40 (v/v) as the mobile phase and ultraviolet (UV) detection at 225 nm. A linear response (r>0.999) was observed over the concentration range of 15-45 μg/ml. The results showed good recoveries, ranging from 98.77 to 101.45% and the relative standard deviation (R.S.D.) intra-day and inter-day were ≤ 0.80%. The peak purity was determined by PDA detector. As the method could effectively separate the drug from its degradation products, it can be used in stability studies for drug substance. RESUMEN. “Validación de un método isocrático de valoración de losartano potásico en tabletas y cápsulas mediante HPLC y ensayos de stress para la evaluación de la estabilida...

A high performance liquid chromatography isocratic procedure was developed for the assay of ketoc... more A high performance liquid chromatography isocratic procedure was developed for the assay of ketoconazole in shampoo. Two solutions, (A) monoisopropylamine-methanol (2:500, v/v) and (B) ammonium acetate-water (1:200, w/v) were prepared. The mobile phase is a mixture of A and B (7:3, v/v), with pH adjusted to 5.5 with acetic acid. The chromatographic system consists of a LiChrospher® 100 RP-8 column (150 x 46 mm, 5 μm), flow rate of 1.0 mL/min and UV detector at 225 nm. The method validation yielded good results. Relative standard deviation (RSD) of 0.42% and accuracy of 97.2% were obtained. Calibration curve was linear between 60.0 and 480.0 μg/mL, with correlation coefficient of 0.9999. RESUMEN. “Cuantificacion de Ketoconazol en Champu por Cromatografia Liquida de Alta Eficiencia”. Fue desarrollado un procedimiento para cuantificar el ketoconazol en champu mediante cromatografia liquida de alta eficiencia. La fase movil consiste en una mezcla de las siguientes soluciones: (A) monois...

International Scientific and Professional …, 2010

The objective of this work was to develop and validate a rapid high performance liquid chromatogr... more The objective of this work was to develop and validate a rapid high performance liquid chromatography (HPLC) method for the quantitative analysis of fluorouracil (5-FU) in polymeric nanoparticles. Chromatographic analyses were performed on an RP C18 column with a mobile phase consisting of acetonitrile and water (10:90, v/v) at a flow rate of 1 mL/min. The 5-FU was detected and quantitated using a photodiode array detector at a wavelength of 265 nm. The method was shown to be specific and linear in the range of 0.1-10 μg/mL (r = 0.9997). The precision (intra-and inter-day) was demonstrated because the maximum relative standard deviation was 3.51%. The method is robust relative to changes in flow rate, column and temperature. The limits of detection and quantitation were 10.86 and 32.78 ng/mL, respectively. The method fulfilled the requirements for reliability and feasibility for application to the quantitative analysis of 5-FU in polymeric nanoparticles. Uniterms: Fluorouracil/determination. Nanoparticles. High performance liquid chromatography/ quantitative analysis/method validation. O objetivo deste trabalho foi desenvolver e validar um método rápido de cromatografia líquida de alta eficiência (CLAE) para análise quantitativa de fluorouracila (5-FU) em nanopartículas poliméricas. Corridas cromatográficas foram realizadas sob uma coluna RP C18 com uma fase móvel consistindo de acetonitrila e água (10:90, v/v) a um fluxo de 1 mL/min. O 5-FU foi detectado e quantificado através de um detector de fotodiodos em um comprimento de onda de 265 nm. O método demonstrou ser específico e linear na faixa de 0,1-10 μg/mL (r =0.9997). As precisões (intra e inter dia) revelaram um desvio padrão relativo máximo de 3,51%. O método é robusto considerando mudanças realizadas no fluxo da fase móvel, temperatura e marca da coluna. Os limites de detecção e quantificação foram de 10,86 e 32,78 ng/mL, respectivamente. O método cumpriu os requisitos para ser considerado confiável e viável para aplicação na análise quantitativa de 5-FU em nanopartículas poliméricas. Unitermos: Fluorouracila/determinação. Nanopartículas. Cromatografia líquida de alta eficiências/ análise quantitativa/validação de método.

Chromatographia, Sep 30, 2005

A simple, selective and accurate high performance liquid chromatographic (HPLC) method was develo... more A simple, selective and accurate high performance liquid chromatographic (HPLC) method was developed and validated for the analysis of esomeprazole magnesium trihydrate (ES) in tablets. Chromatographic separation was achieved isocratically on a C18 column utilizing a mobile phase of acetonitrile/phosphate buffer (60:40, v/v, pH 7) at a flow rate of 1.0 mL/min with UV detection at 205 nm. Lansoprazole was used as an internal standard (IS). The calibration curve of ES was linear in the range of 100~1000 ng/mL (r = 0.9992, n = 4). The RSD values for intra-and inter-day precision were 0.66~0.86% and 0.84~1.11%, respectively. The proposed method was successfully applied to the determination of ES in tablets. The mean recovery for ES from the tablets ranged between 97.82~98.22%. ES was subjected to neutral, acid and alkali hydrolysis as well as oxidation, dry heat treatment and photodegradation. Being simple, accurate and selective, the method can be used for routine quality control analysis.

Revista da Faculdade de Odontologia de Porto Alegre

Os autores estudaram soluções de NaOCI de uso endodOntico, em diferentes concentrações de cloro, ... more Os autores estudaram soluções de NaOCI de uso endodOntico, em diferentes concentrações de cloro, buscando esclarecer os seguintes tópicos: a) Velocidade de "envelhecimento" (perda do teor de cloro) nas diferentes concentrações - 5%, 2,5% - 1% - 0,5% b) Tempo de dissolução de uma polpa dentária (in vitro) das diferentes concentrações. c) Procura de um estabilizador para o NaOCI

Química Nova

Brazilian law forbids the addition of cheese whey in milk. However, adulteration with cheese whey... more Brazilian law forbids the addition of cheese whey in milk. However, adulteration with cheese whey is one of the most applied fraud due to its low cost. The detection of this fraud is the quantification of Caseinomacropeptide (CMP). The CMP is a constituent of the whey that can be used as adulteration marker. Thus, an analytical method capable of identifying CMP by Fourier Transform Infrared Spectra (FTIR) was developed using chemometrics methods. Firstly, we attempted to develop an exploratory analysis model by Hierarchical Grouping Analysis (HCA) and Principal Component Analysis (PCA) that indicated similarity between samples of raw milk and semi-skimmed milk. Moreover, in the PCA scores, it was possible to observe a tendency of separation between samples with different concentrations of CMP. Afterwards, multivariate regression models were used for Partial Least Squares (PLS), Partial Least Square with Interval Synergism (siPLS) and Supporting Machines with Least Squares (LS-SVM) to quantify the adulteration in different types of milk by Cheese serum through the CMP. All the models were then compared to each other and the results of the official method with Liquid Chromatography Tandem mass spectrometry (LCMS/MS) analysis used by the Ministry of Livestock and Supply (MAPA). The model LS-SVM, employing the full spectrum, obtained the best result compared to the other models (PLS and siPLS) to quantify the CMP in the milk samples.

Chemico-biological interactions, 2018

Malaria is one of the most significant infectious diseases that affect poor populations in tropic... more Malaria is one of the most significant infectious diseases that affect poor populations in tropical areas throughout the world. Plants have been shown to be a good source for the development of new antimalarial chemotherapeutic agents, as shown for the discovery of quinine and artemisinin derivatives. Our research group has been working with semisynthetic triterpene derivatives that show potential antimalarial activity toward different strains of Plasmodium falciparum by specifically modulating calcium pathways in the parasite. Promising results were obtained for nanomolar concentrations of the semisynthetic betulinic acid derivative LAFIS13 against the P. falciparum 3D7 strain in vitro, with a selectivity index of 18 compared to a mammalian cell line. Continuing these studies, we present here in vitro and in vivo toxicological evaluations of this compound, followed by docking studies with PfATP6, a sarco/endoplasmic reticulum Ca-ATPase (SERCA) protein. LAFIS13 showed an LD between ...

Pesquisa Agropecuária Brasileira

The objective of this work was to validate a fast method with low-solvent use, for the analysis o... more The objective of this work was to validate a fast method with low-solvent use, for the analysis of trans-resveratrol and quercetin in red wines. The wines were prepared, using a classical method, from the grape (Vitis vinifera) cultivars Cabernet Franc, Cabernet Sauvignon, Malbec, Merlot, Petit Verdot, Pinot Noir, Ruby Cabernet, Syrah, Tannat, and Tempranillo. Samples were filtered and analyzed by high-pressure liquid chromatography (HPLC) with a diode array detector (DAD), at 306 and 371 nm, for trans-resveratrol and quercetin, respectively. An octylsilane column was used, and the mobile phase was composed by a gradient of methanol, water, and formic acid. The method was validated according to the following figures of merit: specificity, linearity, limit of detection, limit of quantification, precision, accuracy, and robustness. The proposed HPLC-DAD method may be established for the analysis of trans-resveratrol and quercetin in red wines.

Chemical Papers

Quantification of bioactive phenols, like stilbenes and flavonols (SaF), has been conducted to ev... more Quantification of bioactive phenols, like stilbenes and flavonols (SaF), has been conducted to evaluate the nutraceutical potential of red wines. However, there is still a lack of full validated, fast and accessible liquid chromatography methods offering high selectivity and a simple procedure. We present here the use of a high-resolution mass spectrometer to evaluate the selectivity of a feasible and traditional liquid chromatography technique (HPLC-DAD) to analyze markers of aglycone SaF in red wines. The SaF compounds were tested: trans-resveratrol, trans-eviniferin, quercetin, myricetin, and kaempferol, as well as trans-cinnamic acid, one of their precursors. System suitability and validation tests were employed for the selected conditions (octylsilane column, methanol mobile phase, and gradient elution). The validation process ensured the HPLC-DAD method was selective, linear, sensitive, precise, accurate and robust. The method was then applied to red wine samples from the Campanha Gaúcha region, Southern Brazil. The real samples contained different SaF levels, showing that the method is applicable to routine use. Furthermore, this was the first SaF characterization of red wines from the Campanha Gaúcha, contributing to regional and product development. Keywords Bioactive phenols Á Red wine Á Liquid chromatography Á Mass spectrometry Á Validation Abbreviations Symbols t R Retention time (min) V/V Volume/volume (%) R s Resolution TF Asymmetry k Capacity factor N Theoretical plates r 2 Coefficient of determination F calc Calculated Fisher value F tab Fisher table value n Number of repetitions p Probability m/z Mass/charge (Da) Greek letters k max Maximum ultraviolet absorption wavelength (nm)

Phytotherapy research : PTR, 2017

Passiflora incarnata L. (Passifloraceae) has been traditionally used for treatment of anxiety, in... more Passiflora incarnata L. (Passifloraceae) has been traditionally used for treatment of anxiety, insomnia, drug addiction, mild infections, and pain. The aim of this study was to investigate the effect of a commercial extract of P. incarnata in the analgesia induced by alcohol withdrawal syndrome in rats. In addition, brain-derived neurotrophic factor and interleukin-10 levels were evaluated in prefrontal cortex, brainstem, and hippocampus. Male adult rats received by oral gavage: (1: water group) water for 19 days, 1 day interval and water (8 days); (2: P. incarnata group) water for 19 days, 1 day interval and P. incarnata 200 mg/kg (8 days); (3: alcohol withdrawal group) alcohol for 19 days, 1 day interval and water (8 days); and (4: P. incarnata in alcohol withdrawal) alcohol for 19 days, 1 day interval and P. incarnata 200 mg/kg (8 days). The tail-flick and hot plate tests were used as nociceptive response measures. Confirming previous study of our group, it was showed that alcoho...

Journal of pharmaceutical and biomedical analysis, Jan 30, 2016

The use of medications during lactation is a common practice; however, pharmacological treatments... more The use of medications during lactation is a common practice; however, pharmacological treatments impose serious doubts to both professionals and nursing mothers regarding the safety of drugs used during this period. Most of drugs are excreted in breast milk and there is great variability in the amount of analytes that can be received by the infant. Dilemmas about breastfeeding arise most commonly in relation to postpartum depression. Depression is a major clinical problem during the postpartum period and the vulnerability to onset or recurrence of depressive symptoms increases the possibility of psychotropic drug use during lactation. Selective inhibitors of serotonin reuptake are commonly prescribed for the treatment of depressive disorders, including fluoxetine, sertraline, citalopram, and paroxetine. A validated bioanalytical method using liquid chromatography coupled to mass spectrometry was developed and validated for determination of antidepressants in human milk following pr...

Rbm Rev Bras Med, May 1, 1995

Resumo: O uso de antibactérianos tópicos tem papel decisivo no controle de infecçoes em queimadur... more Resumo: O uso de antibactérianos tópicos tem papel decisivo no controle de infecçoes em queimaduras. A presente revisao discute vantagens e desvantagens dos fármacos disponíveis para o tratamento de queimados: nitrato de prata, iodopovidona, mafenida, ...

Acta Farmaceutica Bonaerense, 2000

Associações de vitaminas do complexo B estão presentes cada vez mais na forma de medicamentos par... more Associações de vitaminas do complexo B estão presentes cada vez mais na forma de medicamentos para uso humano e veterinário, nas mais diferentes formas de apresentação e, normalmente, combinados com minerais. Tem marcada presença na indústria alimentícia como aditivos alimentares. Por outro lado, essas associações tem sido motivo de preocupação para profissionais do controle de qualidade no que diz respeito ao seu doseamento, uma vez que estão envolvidos diferentes acessórios e equipamentos para determiná-los, com conseqüente aumento do custo de análise. Esse trabalho buscou racionalizar metodologia por CLAE com pareamento iônico, que permite a determinação simultânea de tiamina, riboflavina, piridoxina, nicotinamida e pantotenato de cálcio, em associação com minerais, em duas diferentes soluções orais, uma para uso humano e outra para uso veterinário, envolvendo o menor número possível de equipamentos e acessórios. Para essa associação de vitaminas não existem métodos oficiais para doseamento concomitante de pantotenato de cálcio. Fez-se uso de dois reagentes de pareamento iônico, 409 hexanossulfonato de sódio e heptanossulfonato de sódio, verificando-se ser o segundo o mais adequado para o caso. Dentre diferentes composições de fase móvel testadas, a mais adequada foi a seguinte: heptanossulofonato de sódio 0,005M, 2 mL de ácido acético, 1,5 mL de trietilamina, 15% de metanol e pH 3,0, elevando-se a um volume final de 500 mL.Devido ao pantotenato de cálcio, é necessário trabalhar em dois comprimentos de onda distintos: 210 nm para o pantotenato e 270 nm para as demais vitaminas. Esta fase móvel está sendo adaptada para que o método analítico seja confiável e as determinações possam ser validadas. (CNPq/UFRGS).