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1.
Appetite ; 100: 244-55, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26923742

RESUMO

The dominant taste sensations of three different types of chocolate gelati (milk chocolate, dark chocolate, and bittersweet chocolate) were determined using forty five trained panellists exposed to a silent reference condition and three music samples differing in hedonic ratings. The temporal dominance of sensations (TDS) method was used to measure temporal taste perceptions. The emotional states of panellists were measured after each gelati-music pairing using a scale specifically developed for this study. The TDS difference curves showed significant differences between gelati samples and music conditions (p < 0.05). Sweetness was perceived more dominant when neutral and liked music were played, while bitterness was more dominant for disliked music. A joint Canonical Variate Analysis (CVA) further explained the variability in sensory and emotion data. The first and second dimensions explained 78% of the variance, with the first dimension separating liked and disliked music and the second dimension separating liked music and silence. Gelati samples consumed while listening to liked and neutral music had positive scores, and were separated from those consumed under the disliked music condition along the first dimension. Liked music and disliked music were further correlated with positive and negative emotions respectively. Findings indicate that listening to music influenced the hedonic and sensory impressions of the gelati.


Assuntos
Chocolate , Preferências Alimentares , Sorvetes , Modelos Psicológicos , Música , Prazer , Percepção Gustatória , Adulto , Feminino , Preferências Alimentares/psicologia , Humanos , Masculino , Música/psicologia , Nova Zelândia , Escalas de Graduação Psiquiátrica , Distribuição Aleatória , Adulto Jovem
2.
J Food Sci Technol ; 53(11): 4033-4042, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28035159

RESUMO

Conventional gnocchi are small Italian dumplings made from potatoes, flour, and eggs. In this study, a range of gnocchi-type products containing navy bean and beef meat (10-40% w/w) were developed. The nutritional, physicochemical and sensory properties of the formulated gnocchi were determined, and a Modified in vitro Stomach Stir Tank (MISST) system was used to determine in vitro digestibility. Adding meat significantly increased the fat and protein content of cooked gnocchi type products compared to the control sample. Addition of navy bean and meat also significantly increased hardness, springiness, and chewiness, of most gnocchi type products compared to control sample. In vitro studies showed that pH increased faster in samples high in meat and navy bean content during the initial 30 min to control. The addition of high levels of meat emulsion and navy bean increased, springiness, beany, and meaty flavour. Gnocchi with 20% meat emulsion was similar to control upto some extent being characterized to have flocculent, soft, chewy, and wheaty in flavour. The addition of meat and navy bean did not affect the digestibility of starch in the gastrointestinal tract. Fortified gnocchi with meat and bean was showed a promising vehicle to deliver nutritive values without any changes in starch digestibility.

3.
Analyst ; 138(21): 6262-5, 2013 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-23979112

RESUMO

A multi-dimensional chromatographic approach was developed to measure the free fractions of drug enantiomers in samples that also contained a binding protein or serum. This method, which combined ultrafast affinity extraction with a chiral stationary phase, was demonstrated using the drug warfarin and the protein human serum albumin.


Assuntos
Química Farmacêutica/métodos , Varfarina/análise , Varfarina/química , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Ligação Proteica/fisiologia , Albumina Sérica/metabolismo , Estereoisomerismo , Fatores de Tempo , Varfarina/metabolismo
4.
J Sep Sci ; 34(16-17): 2255-63, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21661111

RESUMO

A noncompetitive peak decay method was used with 1 mm×4.6 mm id silica monoliths to measure the dissociation rate constants (kd) for various drugs with human serum albumin (HSA) and α1-acid glycoprotein (AGP). Flow rates up to 9 mL/min were used in these experiments, resulting in analysis times of only 20-30 s. Using a silica monolith containing immobilized HSA, dissociation rate constants were measured for amitriptyline, carboplatin, cisplatin, chloramphenicol, nortriptyline, quinidine, and verapamil, giving values that ranged from 0.37 to 0.78 s(-1). Similar work with an immobilized AGP silica monolith gave kd values for amitriptyline, nortriptyline, and lidocaine of 0.39-0.73 s(-1). These kd values showed good agreement with values determined for drugs with similar structures and/or affinities for HSA or AGP. It was found that a kd of up to roughly 0.80 s(-1) could be measured by this approach. This information made it possible to obtain a better understanding of the advantages and possible limitations of the noncompetitive peak decay method and in the use of affinity silica monoliths for the high-throughput analysis of drug-protein dissociation.


Assuntos
Cromatografia de Afinidade/métodos , Ensaios de Triagem em Larga Escala/métodos , Orosomucoide/química , Preparações Farmacêuticas/química , Albumina Sérica/química , Dióxido de Silício/química , Cromatografia de Afinidade/instrumentação , Ensaios de Triagem em Larga Escala/instrumentação , Humanos , Cinética , Preparações Farmacêuticas/sangue
5.
Food Chem ; 344: 128601, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33267990

RESUMO

Effect of air velocities, stepwise in-bag ageing and ageing time on the oxidative stability, proteolysis and digestibility of fresh and long-term frozen-stored dry-aged lean beef were studied. Increased air velocities and stepwise ageing regime had no effect (P > 0.05) on dry-aged beef lipid and protein oxidative stabilities and proteolysis pattern compared to control straight-dry-ageing. TBARS, protein carbonyl and free amino acids (FAAs) increased (P > 0.05) with ageing time. In-bag dry-ageing of beef improved its lipids and protein oxidative stability during long-term frozen storage compared to unaged beef. Improvement in beef protein digestibility was observed through increased release of FAAs and appearance of small protein fragments from SDS-PAGE in dry-aged samples compared to the unaged. The high lipid and protein oxidative stability of long-term frozen lean beef produced using stepwise in-bag ageing process suggest potential for the process to be used for producing dry-aged meat for export.


Assuntos
Manipulação de Alimentos/métodos , Carne/análise , Proteínas/metabolismo , Aminoácidos/análise , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Dessecação , Digestão , Eletroforese em Gel de Poliacrilamida , Congelamento , Oxirredução , Proteínas/química , Proteólise , Fatores de Tempo
6.
Meat Sci ; 181: 108438, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33589342

RESUMO

Rapid Evaporative Ionisation Mass Spectrometry (REIMS) was used to determine the impact of in-bag ageing regimes (stepwise-ageing at different air velocities and straight-dry-ageing) and trimming on the metabolic profile of dry-aged lean beef. Orthogonal projection to latent structures-discriminant analysis (OPLS-DA) models based on 1705 tentatively identified m/z features were found for ageing methods (Q2 = 0.85), ageing time (0 vs. 21 days, Q2 = 0.95) and sampling locations (surface meat vs. trimmings, Q2 = 0.94). No significant (P > 0.05) difference in metabolites due to air velocities. Small metabolites such as dipeptides and amino acids were more abundant, especially on the surface of untrimmed lean beef, following 21 days of straight-dry-ageing. Stepwise-ageing produced different metabolic profiles from straight-dry-ageing, suggesting that the two methods may differ in dry-aged meat quality and flavour. This work demonstrates REIMS's potential for real time differentiation of meat on processing parameters.


Assuntos
Manipulação de Alimentos/métodos , Espectrometria de Massas/veterinária , Carne Vermelha/análise , Animais , Bovinos , Análise Discriminante , Espectrometria de Massas/métodos , Músculo Esquelético
7.
Food Chem ; 347: 128999, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33465687

RESUMO

The effect of in-bag dry- and wet-ageing on metabolite profiles of lamb legs was determined using Rapid Evaporative Ionisation Mass Spectrometry (REIMS). Using orthogonal projection to latent structures-discriminant analysis (OPLS-DA) with REIMS, 1705 metabolite ions were identified (Q2 = 0.86) in four muscles: m. semimembranosus, m. biceps femoris, m. vastus lateralis and m. rectus femoris. A total of 663 metabolites differed between ageing methods (P < 0.05) which mainly resulted from proteolysis and lipid metabolism. Dry-aged lamb had higher pH (P = 0.016) and lower moisture content (P = 0.034) than the wet-aged. Dry-ageing produced more (P < 0.05) smaller sized metabolites including dipeptides and free amino acids and lipid oxidation metabolites compared to wet-aged equivalents. Different muscles had distinct REIMS metabolic profiles. Outcomes of this study demonstrated that REIMS can be used for authentication between in-bag dry- and wet-aged lamb based on their metabolic fingerprints.


Assuntos
Dessecação/métodos , Espectrometria de Massas/métodos , Metaboloma , Músculo Esquelético/metabolismo , Aminoácidos/análise , Animais , Cromatografia Líquida de Alta Pressão , Análise Discriminante , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Análise dos Mínimos Quadrados , Metabolismo dos Lipídeos , Proteínas Musculares/análise , Proteólise , Carne Vermelha/análise , Ovinos , Fatores de Tempo
8.
Foods ; 10(1)2020 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375684

RESUMO

The aim of this study was to produce in-bag dry-aged lamb and compare its meat quality, consumer acceptability, oxidative stability and in vitro digestibility to the wet-aged equivalents. Significantly higher pH, weight loss and reduced cook loss were observed in dry-aged lamb compared to the wet-aged (p < 0.0001). Dry-aged lamb had harder and chewier texture profiles and lower colour attributes (L*, a* and b*) than the wet-aged (p < 0.001). The dry-aged and wet-aged lamb were equally preferred (around 40% each) by the consumer panel, underpinning the niche nature of dry-aged meat. Significantly (p < 0.05) higher yeast and thiobarbituric acid reactive substances (TABRS) levels were observed in dry-aged lamb compared to the wet-aged. There was no difference in fatty acid profile, protein carbonyl content and pattern of proteolysis between ageing regimes (p > 0.05). Ageing regimes had no impact on overall digestibility; however, a greater gastric digestibility was observed in dry-aged lamb through the increased release of free amino acids (FAAs) compared to the wet-aged. Outcomes of this study demonstrated for the first time the possibility of producing dry-aged lamb legs of acceptable quality, oxidative stability and superior digestibility compared to the equivalent wet-aged lamb.

9.
J Sep Sci ; 32(15-16): 2776-85, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19630007

RESUMO

Silica monoliths in affinity microcolumns were tested for the high-throughput analysis of drug-protein interactions. HSA was used as a model protein for this work, while carbamazepine and R-warfarin were used as model analytes. A comparison of HSA silica monoliths of various lengths indicated columns as short as 1 to 3 mm could be used to provide reproducible estimates of retention factors or plate heights. Benefits of using smaller columns for this work included the lower retention times and lower back pressures that could be obtained versus traditional HPLC affinity columns, as well as the smaller amount of protein that is required for column preparation. One disadvantage of decreasing column length was the lower precision that resulted in retention factor and plate height measurements. A comparison was also made between microcolumns containing silica particles versus silica monoliths. It was demonstrated with R-warfarin that supports could be used in HSA microcolumns for the determination of retention factors or plate heights. However, the higher efficiency of the silica monolith made this the preferred support for work at higher flow rates or when a larger number of plates are needed during the rapid analysis of drug-protein interactions.


Assuntos
Carbamazepina/isolamento & purificação , Cromatografia Líquida de Alta Pressão/instrumentação , Albumina Sérica/isolamento & purificação , Dióxido de Silício/química , Varfarina/isolamento & purificação , Anticoagulantes/isolamento & purificação , Anticonvulsivantes/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Estrutura Molecular , Albumina Sérica/química
10.
J Sep Sci ; 32(5-6): 835-53, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19278006

RESUMO

The binding of drugs with proteins in blood, serum, or plasma is an important process in determining the activity, distribution, rate of excretion, and toxicity of drugs in the body. High-performance affinity chromatography (HPAC) has received a great deal of interest as a means for studying these interactions. This review examines the various techniques that have been used in HPAC to examine drug-protein binding and discusses the types of information that can be obtained through this approach. A comparison of these techniques with traditional methods for binding studies (e.g., equilibrium dialysis and ultrafiltration) will also be presented. The use of HPAC with specific serum proteins and binding agents will then be discussed, including HSA and alpha(1)-acid glycoprotein (AGP). Several examples from the literature are provided to illustrate the applications of such research. Recent developments in this field are also described, such as the use of improved immobilization techniques, new data analysis methods, techniques for working directly with complex biological samples, and work with immobilized lipoproteins. The relative advantages and limitations of the methods that are described will be considered and the possible use of these techniques in the high-throughput screening or characterization of drug-protein binding will be discussed.


Assuntos
Proteínas Sanguíneas/metabolismo , Preparações Farmacêuticas/sangue , Sítios de Ligação , Proteínas Sanguíneas/análise , Cromatografia Líquida de Alta Pressão
11.
Artigo em Inglês | MEDLINE | ID: mdl-18980867

RESUMO

The binding of verapamil to the protein human serum albumin (HSA) was examined by using high-performance affinity chromatography. Many previous reports have investigated the binding of verapamil with HSA, but the exact strength and nature of this interaction (e.g. the number and location of binding sites) is still unclear. In this study, frontal analysis indicated that at least one major binding site was present for R- and S-verapamil on HSA, with estimated association equilibrium constants on the order of 10(4)M(-1) and a 1.4-fold difference in these values for the verapamil enantiomers at pH 7.4 and 37 degrees C. The presence of a second, weaker group of binding sites on HSA was also suggested by these results. Competitive binding studies using zonal elution were carried out between verapamil and various probe compounds that have known interactions with several major and minor sites on HSA. R/S-Verapamil was found to have direct competition with S-warfarin, indicating that verapamil was binding to Sudlow site I (i.e. the warfarin-azapropazone site of HSA). The average association equilibrium constant for R- and S-verapamil at this site was 1.4 (+/-0.1)x10(4)M(-1). Verapamil did not have any notable binding to Sudlow site II of HSA but did appear to have some weak allosteric interactions with l-tryptophan, a probe for this site. An allosteric interaction between verapamil and tamoxifen (a probe for the tamoxifen site) was also noted, which was consistent with the binding of verapamil at Sudlow site I. No interaction was seen between verapamil and digitoxin, a probe for the digitoxin site of HSA. These results gave good agreement with previous observations made in the literature and help provide a more detailed description of how verapamil is transported in blood and of how it may interact with other drugs in the body.


Assuntos
Cromatografia de Afinidade/métodos , Albumina Sérica/metabolismo , Verapamil/sangue , Sítios de Ligação , Ligação Competitiva , Interações Medicamentosas , Humanos , Ligação Proteica , Estereoisomerismo , Tamoxifeno/sangue , Triptofano/sangue , Varfarina/sangue
12.
Food Chem ; 254: 317-325, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29548459

RESUMO

Bresaola made from New Zealand mutton and lamb, were compared in quality attributes. Mutton bresaola had slightly lower protein and higher moisture contents, and similar amount of intramuscular fat and instrumental colour compared to that of the lamb. 36 and 80 unique endogenous peptides were observed in mutton and lamb, respectively. Proteolysis during dry-curing was affected by the age of the animal and has resulted in softer and easier to chew textural properties to the mutton bresaola. Significantly higher amounts of total free amino acids and higher proportion of essential amino acids were detected in the mutton bresaola from digestion simulation compared to that from lamb. Expedited proteolysis measured in the form of the release of free amino acids was positively related to the animal age. Overall, bresaola from mutton had more favourable characteristics compared to that of the lamb.


Assuntos
Qualidade dos Alimentos , Produtos da Carne , Carneiro Doméstico , Fatores Etários , Aminoácidos Essenciais/análise , Animais , Cor , Digestão , Manipulação de Alimentos/métodos , Produtos da Carne/análise , Nova Zelândia , Valor Nutritivo , Proteólise
13.
Food Res Int ; 104: 134-142, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29433778

RESUMO

Red meat enriched versions of bread, spaghetti, yoghurt, ice cream and chocolate were prototyped and assessed for some of their physical, chemical and microbiological properties, as well as sensory appeal. The protein content of the products were significantly increased and their colour went darker with meat enrichment (p<0.05). Bread volume and spaghetti tensile strength increased and ice cream meltability and yoghurt apparent viscosity decreased with meat enrichment (p<0.05). The overall acceptability/liking of bread, flavoured ice cream and spaghetti were not affected (p>0.05) but that of non-flavoured ice cream and yoghurt went down (p<0.05) with meat enrichment. 75% of the 940 panellist who ate the meat-enriched chocolates either loved or slightly-liked them. The outcome of the present study would assist in making the nutrition of meat available in a wider range of product categories, helping the meat industry stretch its established business models, and encouraging further development of novel food choices for elderly and other groups of consumers.


Assuntos
Comportamento Alimentar , Manipulação de Alimentos/métodos , Alimentos Fortificados , Proteínas de Carne/análise , Valor Nutritivo , Carne Vermelha/análise , Fatores Etários , Cor , Comportamento do Consumidor , Elasticidade , Dureza , Humanos , Paladar , Resistência à Tração , Viscosidade
14.
Food Chem ; 242: 162-168, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29037673

RESUMO

This is the first study to investigate the extent of reduction in acrylamide formation during baking with the addition of (-)-epigallocatechin gallate (EGCG) extracted from green tea, and to determine whether EGCG influences the texture and colour attributes of bread, or interacts with other ingredients. EGCG powders were added to white bread formulations at the concentrations of 3.3, 6.6 and 9.9g·kg-1. The amount of acrylamide in the bread was analysed using liquid chromatography-mass spectrometry. EGCG addition significantly reduced the acrylamide formation by 37% compared to the control and decreased the moisture content of the bread by 6%. It did not affect its texture attribute, but increased the lightness and the yellowness and decreased the redness of bread crust (with contrasting results in crumb). It also decreased granule size and porosity. In conclusion, EGCG fortification is a feasible method to decrease acrylamide formation in baked bread.


Assuntos
Acrilamida/química , Pão , Catequina/análogos & derivados , Chá/química , Catequina/química , Catequina/isolamento & purificação , Triticum/química
15.
J Chromatogr A ; 1218(15): 2072-8, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20956006

RESUMO

This report examined the use of silica monoliths in affinity microcolumns containing human serum albumin (HSA) to measure the dissociation rates for various drugs from this protein. Immobilized HSA and control monolith columns with dimensions of 1 mm × 4.6 mm i.d. were prepared for this work and used with a noncompetitive peak decay method. Several drugs known to bind HSA were examined, such as warfarin, diazepam, imipramine, acetohexamide, and tolbutamide. Items that were studied and optimized in this method included the sample volume, sample concentration, and elution flow rate. It was found that flow rates up to 10 mL/min could be used in this approach. Work with HSA silica monoliths at these high flow rates made it possible to provide dissociation rate constants for drugs such as warfarin in less than 40s. The dissociation rate constants that were measured gave good agreement with values reported in the literature or that had been obtained with other solutes that had similar binding affinities for HSA. This approach is a general one that should be useful in examining the dissociation of other drugs from HSA and in providing a high-throughput method for screening drug-protein interactions.


Assuntos
Cromatografia de Afinidade , Proteínas Imobilizadas/metabolismo , Preparações Farmacêuticas/metabolismo , Dióxido de Silício/química , Cromatografia de Afinidade/instrumentação , Cromatografia de Afinidade/métodos , Ensaios de Triagem em Larga Escala , Humanos , Proteínas Imobilizadas/química , Cinética , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Ligação Proteica , Albumina Sérica/química , Albumina Sérica/metabolismo
16.
J Food Sci ; 76(2): R49-61, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21535784

RESUMO

Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.


Assuntos
Alimentos , Boca/fisiologia , Percepção Gustatória , Paladar/fisiologia , Fenômenos Químicos , Deglutição , Ingestão de Alimentos , Módulo de Elasticidade , Humanos , Mastigação , Odorantes , Percepção Olfatória , Reologia
17.
Curr Drug Metab ; 12(4): 313-28, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21395530

RESUMO

The binding of drugs with serum proteins can affect the activity, distribution, rate of excretion, and toxicity of pharmaceutical agents in the body. One tool that can be used to quickly analyze and characterize these interactions is high-performance affinity chromatography (HPAC). This review shows how HPAC can be used to study drug-protein binding and describes the various applications of this approach when examining drug interactions with serum proteins. Methods for determining binding constants, characterizing binding sites, examining drug-drug interactions, and studying drug-protein dissociation rates will be discussed. Applications that illustrate the use of HPAC with serum binding agents such as human serum albumin, α(1)-acid glycoprotein, and lipoproteins will be presented. Recent developments will also be examined, such as new methods for immobilizing serum proteins in HPAC columns, the utilization of HPAC as a tool in personalized medicine, and HPAC methods for the high-throughput screening and characterization of drug-protein binding.


Assuntos
Proteínas Sanguíneas/química , Proteínas Sanguíneas/metabolismo , Cromatografia de Afinidade/métodos , Cromatografia Líquida de Alta Pressão/métodos , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Sítios de Ligação , Interações Medicamentosas , Humanos , Ligação Proteica
18.
Anal Methods ; 3(7)2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24223625

RESUMO

The binding of drugs with serum proteins and binding agents such as human serum albumin, α1-acid glycoprotein, and lipoproteins is an important process in determining the activity and fate of many pharmaceuticals in the body. A variety of techniques have been used to study drug interactions with serum proteins, but there is still a need for faster or better methods for such work. High-performance liquid chromatography (HPLC) is one tool that has been utilized in many formats for these types of measurements. Advantages of using HPLC for this application include its speed and precision, its ability to be automated, its good limits of detection, and its compatibility with a wide range of assay formats and detectors. This review will discuss various approaches in which HPLC can be employed for the study of drug-protein interactions. These techniques include the use of soluble proteins in zonal elution and frontal analysis methods or vacancy techniques such as the Hummel-Dreyer method. Zonal elution and frontal analysis methods that make use of immobilized proteins and high-performance affinity chromatography will also be presented. A variety of applications will be examined, ranging from the determination of free drug fractions to the measurement of the strength or rate of a drug-protein interaction. Newer developments that will be discussed include recent work in the creation of novel mathematical approaches for HPLC studies of drug-protein binding, the use of HPLC methods for the high-throughput screening of drug-protein binding, and the creation and use of affinity monoliths or affinity microcolumns for examining drug-protein systems.

19.
J Chromatogr B Analyt Technol Biomed Life Sci ; 878(20): 1707-13, 2010 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20462808

RESUMO

This study examined the use of affinity microcolumns as tools for the rapid analysis and high-throughput screening of drug-protein binding. The protein used was immobilized human serum albumin (HSA) and the model analytes were warfarin and L-tryptophan, two solutes often used as site-specific probes for drug binding to Sudlow sites I and II of HSA, respectively. The use of HSA microcolumns in binding studies was examined by using both zonal elution and frontal analysis formats. The zonal elution studies were conducted by injecting the probe compounds onto HSA microcolumns of varying lengths while measuring the resulting retention factors, plate heights and peak asymmetries. A decrease in the retention factor was noted when moving from longer to shorter column lengths while using a constant amount of injected solute. However, this change could be corrected, in part, by determining the relative retention factor of a solute versus a reference compound injected onto the same microcolumn. The plate height values were relatively consistent for all column lengths and gave an expected increase at higher linear velocities. The peak asymmetries were similar for all columns up to 1 mL/min but shifted to larger values at higher flow rates and when using short microcolumns (e.g., 1 mm length). The association equilibrium constants and number of binding sites estimated by frontal analysis for warfarin with HSA were consistent at the various column sizes that were tested and gave good agreement with previous literature values. These results confirmed affinity microcolumns provide comparable results to those obtained with longer columns and can be used in the rapid analysis of drug-protein binding and in the high-throughput screening of such interactions.


Assuntos
Cromatografia de Afinidade/métodos , Albumina Sérica/química , Triptofano/química , Varfarina/química , Humanos , Cinética , Preparações Farmacêuticas/química , Ligação Proteica
20.
J Chromatogr B Analyt Technol Biomed Life Sci ; 878(7-8): 705-8, 2010 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-20138813

RESUMO

High-performance affinity chromatography was used to study binding by the drug lidocaine to human serum albumin (HSA) and alpha(1)-acid glycoprotein (AGP). AGP had strong binding to lidocaine, with an association equilibrium constant (K(a)) of 1.1-1.7 x 10(5) M(-1) at 37 degrees C and pH 7.4. Lidocaine had weak to moderate binding to HSA, with a K(a) in the range of 10(3) to 10(4) M(-1). Competitive experiments with site selective probes showed that lidocaine was interacting with Sudlow site II of HSA and the propranolol site of AGP. These results agree with previous observations in the literature and provide a better quantitative understanding of how lidocaine binds to these serum proteins and is transported in the circulation. This study also demonstrates how HPAC can be used to examine the binding of a drug with multiple serum proteins and provide detailed information on the interaction sites and equilibrium constants that are involved in such processes.


Assuntos
Cromatografia de Afinidade/métodos , Lidocaína/metabolismo , Orosomucoide/metabolismo , Albumina Sérica/metabolismo , Ligação Competitiva , Humanos , Cinética , Lidocaína/química , Modelos Lineares , Orosomucoide/química , Propranolol/química , Ligação Proteica , Albumina Sérica/química
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