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1.
J Genet Couns ; 27(2): 323-325, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29204808

RESUMO

Aurora Health Care in eastern Wisconsin has a clinical genetics program driven by genetic counselors in the cancer/adult and prenatal genetics settings. In 2015, the workforce shortage of genetic counselors left us with 4 open positions for genetic counselors that we were unable to fill. We explored many models of alternative service delivery, and determined virtual health (VH) via telemedicine to be the best option for our system. Historically, telemedicine technologies have been used to provide access to healthcare services to patients in remote areas. We, however, were struggling to find genetics counselors to staff both our remote clinics and urban clinics. To solve this problem, we recruited genetic counselors from across the country to work remotely from their current home or home office utilizing VH to staff our clinics. We then created clinical workflows and an implementation process of virtual health for 9 prenatal and cancer clinics across the eastern Wisconsin footprint of our healthcare system over the course of 12 months. Here we provide our experience and process in establishing a VH program in order to help other institutions that have been affected by the workforce shortage of clinical genetics professionals.


Assuntos
Serviços de Saúde Comunitária/organização & administração , Aconselhamento Genético , Telemedicina/organização & administração , Adulto , Feminino , Humanos , Gravidez , Wisconsin
2.
Headache ; 57(1): 17-20, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27704538

RESUMO

BACKGROUND: This retrospective observational study describes what appears to be a not-uncommon yet not previously typified headache disorder, "end-menstrual migraine" (EMM) named for its proximate occurrence with the terminal days of menstrual bleeding each month. METHODS: Our menstrual migraine (MM) clinic's database was queried for patients with migraine, regular menses, and the locally used diagnostic code of EMM, signifying the patient's assertion that she had migraine at the end of menses as well as calendar data confirming that association. Serum ferritin levels were available for all subjects with EMM. RESULTS: Among the most recently seen 119 women in the clinic, 85 had both regular menses and a diagnosis of migraine, and were thus appropriate for evaluation. In this selected population, 30 women (35.3%) were confirmed to have EMM. Twenty-eight of those 30 patients (93.3%) had ferritin levels that fell below the generally accepted lower desirable limit of 50 ng/mL (mean = 21.9 ng/mL) - half of whom fell below 18 ng/mL, the established minimum levels for women. CONCLUSIONS: EMM is a common complaint in women evaluated for menstrual-related migraine (MRM), yet these migraines occur many days after the estrogen withdrawal that precipitates MRM. The authors do not believe that EMM is hormonally mediated, but rather that it is causally related to menstrual blood loss, resulting in a brief relative anemia with consequent migraine. Further study is needed to substantiate this association, search for confounders, and evaluate response to iron therapy.


Assuntos
Menstruação/fisiologia , Transtornos de Enxaqueca/fisiopatologia , Adulto , Feminino , Ferritinas/sangue , Hormônios/metabolismo , Humanos , Estudos Retrospectivos
3.
Headache ; 56(2): 240-58, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26615983

RESUMO

The sphenopalatine ganglion (SPG) has attracted the interest of practitioners treating head and face pain for over a century because of its anatomical connections and role in the trigemino-autonomic reflex. In this review, we discuss the anatomy of the SPG, as well as what is known about its role in the pathophysiology of headache disorders, including cluster headache and migraine. We then address various therapies that target the SPG, including intranasal medication delivery, new SPG blocking catheter devices, neurostimulation, chemical neurolysis, and ablation procedures.


Assuntos
Gânglios Autônomos/anatomia & histologia , Gânglios Autônomos/fisiologia , Cefaleia , Bloqueio do Gânglio Esfenopalatino/métodos , Animais , Cefaleia/patologia , Cefaleia/fisiopatologia , Cefaleia/terapia , Humanos
4.
Adv Drug Deliv Rev ; 199: 114831, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37100206

RESUMO

Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.


Assuntos
Pulmão , Vacinas , Humanos , Aerossóis , Imunoterapia , Sistemas de Liberação de Medicamentos
5.
J Pharm Sci ; 111(3): 699-709, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34808214

RESUMO

The measurement of polydisperse protein aggregates and particles in biotherapeutics remains a challenge, especially for particles with diameters of ≈ 1 µm and below (sub-micrometer). This paper describes an interlaboratory comparison with the goal of assessing the measurement variability for the characterization of a sub-micrometer polydisperse particle dispersion composed of five sub-populations of poly(methyl methacrylate) (PMMA) and silica beads. The study included 20 participating laboratories from industry, academia, and government, and a variety of state-of-the-art particle-counting instruments. The received datasets were organized by instrument class to enable comparison of intralaboratory and interlaboratory performance. The main findings included high variability between datasets from different laboratories, with coefficients of variation from 13 % to 189 %. Intralaboratory variability was, on average, 37 % of the interlaboratory variability for an instrument class and particle sub-population. Drop-offs at either end of the size range and poor agreement on maximum counts of particle sub-populations were noted. The mean distributions from an instrument class, however, showed the size-coverage range for that class. The study shows that a polydisperse sample can be used to assess performance capabilities of an instrument set-up (including hardware, software, and user settings) and provides guidance for the development of polydisperse reference materials.


Assuntos
Laboratórios , Software , Tamanho da Partícula
6.
BMC Res Notes ; 13(1): 385, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32799916

RESUMO

OBJECTIVE: The aim is to perform a pilot study evaluating the differences in healthcare service use and its associated costs by infant feeding mode in an infant's first year of life. Data from a prospective cohort study and administrative databases were linked to examine healthcare use in healthy full term infants (N = 160). Exposure was categorized as exclusively breastfed, mixed fed and exclusively formula fed. Outcomes included hospitalizations, emergency room and physician visits. Descriptive statistics and generalized linear modelling were performed. RESULTS: Overall $315,235 was spent on healthcare service use for the sample of infants during their first year of life. When compared to exclusive breastfeeding, mixed feeding and exclusive formula feeding were found to be significant predictors of total healthcare service use costs (p < 0.05), driven by costs of hospital admissions. Due to the human and economic burden associated with not breastfeeding, policies and programs that support and encourage breastfeeding should be priority.


Assuntos
Aleitamento Materno , Fórmulas Infantis , Canadá , Feminino , Humanos , Lactente , Armazenamento e Recuperação da Informação , Projetos Piloto , Estudos Prospectivos
7.
PLoS One ; 14(5): e0216406, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31071134

RESUMO

Biological and bioinspired polymer microparticles have broad biomedical and industrial applications, including drug delivery, tissue engineering, surface modification, environmental remediation, imaging, and sensing. Full realization of the potential of biopolymer microparticles will require methods for rigorous characterization of particle sizes, morphologies, and dynamics, so that researchers may correlate particle characteristics with synthesis methods and desired functions. Toward this end, we evaluated biopolymer microparticles using flow imaging microscopy. This technology is widely used in the biopharmaceutical industry but is not yet well-known among the materials community. Our polymer, a genetically engineered elastin-like polypeptide (ELP), self-assembles into micron-scale coacervates. We performed flow imaging of ELP coacervates using two different instruments, one with a lower size limit of approximately 2 microns, the other with a lower size limit of approximately 300 nanometers. We validated flow imaging results by comparison with dynamic light scattering and atomic force microscopy analyses. We explored the effects of various solvent conditions on ELP coacervate size, morphology, and behavior, such as the dispersion of single particles versus aggregates. We found that flow imaging is a superior tool for rapid and thorough particle analysis of ELP coacervates in solution. We anticipate that researchers studying many types of microscale protein or polymer assemblies will be interested in flow imaging as a tool for quantitative, solution-based characterization.


Assuntos
Sistemas de Liberação de Medicamentos , Elastina/química , Microscopia , Avaliação Pré-Clínica de Medicamentos
8.
J Hum Lact ; 34(1): 20-29, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29182888

RESUMO

BACKGROUND: The 17-item Iowa Infant Feeding Attitude Scale (IIFAS) has been widely used to assess maternal attitudes toward infant feeding and to predict breastfeeding intention. The IIFAS has been validated among prenatal women located in Newfoundland and Labrador in Canada, although its length may prove challenging to complete in a clinical setting. Research aim: The authors aimed to reduce the number of items from the original 17-item IIFAS scale while maintaining reliability and validity. METHODS: A nonexperimental cross-sectional design was used among 1,283 women in their third trimester residing in Newfoundland and Labrador. Data were collected from August 2011 to June 2016. An exploratory factor analysis using principal component analysis was performed to explore the underlying structure of the IIFAS. The internal consistency of both the 17-item and reduced version was assessed using Cronbach's alpha and item-total correlation. The area under the curve and linear regression model were used to assess predictive validity of intention to breastfeed. RESULTS: Our findings revealed that a 13-item IIFAS (Cronbach's α = .870) had relatively similar internal consistency to the original IIFAS (Cronbach's α = .868). Three themes were extracted from the factor analysis, resulting in the removal of four items. The reduced scale demonstrated an excellent ability to predict breastfeeding intention (area under the curve = 0.914). CONCLUSION: The reduced 13-item version of the IIFAS is a psychometrically sound instrument that maintains its accuracy and validity when measuring maternal feeding attitudes during pregnancy and can be more time efficient in clinical settings compared with the 17-item IIFAS.


Assuntos
Ciências da Nutrição Infantil/normas , Conhecimentos, Atitudes e Prática em Saúde , Gestantes/psicologia , Psicometria/normas , Adulto , Alimentação com Mamadeira/psicologia , Alimentação com Mamadeira/normas , Aleitamento Materno/psicologia , Ciências da Nutrição Infantil/métodos , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Terra Nova e Labrador , Gravidez , Terceiro Trimestre da Gravidez , Cuidado Pré-Natal/métodos , Psicometria/instrumentação , Psicometria/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários
9.
J Hum Lact ; 34(4): 691-698, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29742357

RESUMO

BACKGROUND: The original 17-item Iowa Infant Feeding Attitude Scale (IIFAS) has been validated and widely used to assess attitudes toward breastfeeding. A reduced 13-item version of the IIFAS was recently validated in a Canadian setting. However, cutoff scores for categorization of infant feeding attitudes on both scales have not yet been established. Research Aim: The aim of this study was to determine optimal cut-ff scores predicting infant feeding attitudes and outcomes for the original and reduced IIFASs. METHODS: A population-based prospective cohort study was undertaken in the Canadian province of Newfoundland and Labrador. A sample of 658 pregnant women were followed up to 1 month postpartum. The receiver operating curve and Youden index were assessed to identify the sensitivity and specificity of cutoff scores. The magnitude at which these scores predicted postpartum feeding outcomes was evaluated using linear regression. RESULTS: Scores of ≤60 (sensitivity = 0.81, specificity = 0.87) and ≤45 (sensitivity = 0.84, specificity = 0.83) for the 17-item and 13-item IIFASs, respectively, were found to be optimal cutoff scores for predicting negative breastfeeding attitudes. The cutoff score for the reduced IIFAS version maintained its ability to predict women who formula-fed at 1 month postpartum (adjusted odds ratio = 6.32, 95% confidence interval = 1.84-11.61) compared with the original scale (adjusted odds ratio = 4.62, 95% confidence interval = 2.42-16.52). CONCLUSION: The proposed cutoff scores for the original and reduced IIFASs have excellent predictive ability to determine infant feeding attitudes and outcomes. The classification of scores enhances the use and applicability of the IIFAS.


Assuntos
Atitude Frente a Saúde , Aleitamento Materno/psicologia , Comportamento Alimentar/psicologia , Cuidado do Lactente/classificação , Gestantes/psicologia , Adulto , Estudos de Coortes , Comportamento Alimentar/classificação , Feminino , Política de Saúde , Humanos , Lactente , Cuidado do Lactente/métodos , Cuidado do Lactente/normas , Estudos Longitudinais , Terra Nova e Labrador , Razão de Chances , Gravidez , Cuidado Pré-Natal/classificação , Cuidado Pré-Natal/métodos , Cuidado Pré-Natal/normas , Psicometria/instrumentação , Psicometria/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários
10.
J Hum Lact ; 33(2): 278-284, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28418804

RESUMO

BACKGROUND: Despite high rates of intention to exclusively breastfeed, rates of exclusive breastfeeding in Canada are low. Supplementation may begin in hospital and is associated with reduced breastfeeding duration. Research aim: The aim of this investigation was to explore determinants of in-hospital nonmedically indicated supplementation of infants whose birthing parents intended to exclusively breastfeed. METHODS: This study is a cross-sectional one-group nonexperimental design, focused on participants who intended to exclusively breastfeed for 6 months ( n = 496). Data were collected between October 2011 and October 2015 in Newfoundland and Labrador. Variables measured included age; rural/urban location; education; income; race; marital status; parity; smoking status; having been breastfed as an infant; previous breastfeeding experience; Iowa Infant Feeding Attitude Scale score; delivery mode; infant birth weight; birth satisfaction; skin-to-skin contact; length of participant's hospital stay; breastfeeding advice from a lactation consultant, registered nurse, or physician; and first impression of breastfeeding. We evaluated determinants of in-hospital nonmedically indicated supplementation using bivariate and multivariate logistic regression analyses. RESULTS: Overall, 16.9% ( n = 84) of infants received nonmedically indicated supplementation in hospital. Multivariate modeling revealed four determinants: low total prenatal Iowa Infant Feeding Attitude Scale score (odds ratio [OR] = 1.96, 95% confidence interval [CI] [1.18, 3.27]), no previous breastfeeding experience (OR = 2.03, 95% CI [1.15, 3.61]), negative first impression of breastfeeding (OR = 2.67, 95% CI [1.61, 4.43]), and receiving breastfeeding advice from a hospital physician (OR = 2.86, 95% CI [1.59, 5.15]). CONCLUSION: Elements of the hospital experience, self-efficacy, and attitudes toward infant feeding are determinants of nonmedically indicated supplementation of infants whose birthing parents intended to exclusively breastfeed.


Assuntos
Aleitamento Materno/estatística & dados numéricos , Suplementos Nutricionais/estatística & dados numéricos , Comportamento Alimentar , Intenção , Pais/psicologia , Adolescente , Adulto , Aleitamento Materno/psicologia , Estudos de Coortes , Feminino , Humanos , Lactente , Fórmulas Infantis/estatística & dados numéricos , Recém-Nascido , Estudos Longitudinais , Terra Nova e Labrador , Autorrelato , Inquéritos e Questionários
11.
Health Equity ; 1(1): 96-102, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30283838

RESUMO

Purpose: Infant feeding differences are strongly tied to socioeconomic status. The goal of this study is to compare determinants of early breastfeeding cessation incidence in socioeconomically marginalized (SEM) and socioeconomically privileged (SEP) populations, focusing on birthing parents who intended to breastfeed. Methods: This cohort study includes data from 451 birthing parents in the Canadian province of Newfoundland and Labrador who reported intention to breastfeed in the baseline prenatal survey. Multivariate logistic regression techniques were used to assess the determinants of breastfeeding cessation at 1 month in both SEM and SEP populations. Results: The analysis data included 73 SEM and 378 SEP birthing parents who reported intention to breastfeed at baseline. At 1 month, 24.7% (18/73) in the SEM group had ceased breastfeeding compared to 6.9% (26/378) in the SEP group. In the SEP population, score on the Iowa Infant Feeding Attitude Scale (IIFAS) (odds ratio [OR] 3.33, p=0.01) was the sole significant determinant. In the SEM population, three significant determinants were identified: unpartnered marital status (OR 5.10, p=0.05), <1 h of skin-to-skin contact after birth (OR 11.92, p=0.02), and negative first impression of breastfeeding (OR 11.07, p=0.01). Conclusion: These results indicate that determinants of breastfeeding cessation differ between SEM and SEP populations intending to breastfeed. Interventions intended on improving the SEM population's postpartum breastfeeding experience using best practices, increasing support, and ensuring at least 1 h of skin-skin contact may increase breastfeeding rates.

12.
J Hum Lact ; 32(3): NP9-NP18, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25425631

RESUMO

BACKGROUND: Maternal attitudes to infant feeding are predictive of intent and initiation of breastfeeding. OBJECTIVES: The Iowa Infant Feeding Attitude Scale (IIFAS) has not been validated in the Canadian population. This study was conducted in Newfoundland and Labrador, a Canadian province with low breastfeeding rates. Objectives were to assess the reliability and validity of the IIFAS in expectant mothers; to compare attitudes to infant feeding in urban and rural areas; and to examine whether attitudes are associated with intent to breastfeed. METHODS: The IIFAS assessment tool was administered to 793 pregnant women. Differences in the total IIFAS scores were compared between urban and rural areas. Reliability and validity analysis was conducted on the IIFAS. The receiver operating characteristic (ROC) of the IIFAS was assessed against mother's intent to breastfeed. RESULTS: The mean ± SD of the total IIFAS score of the overall sample was 64.0 ± 10.4. There were no significant differences in attitudes between urban (63.9 ± 10.5) and rural (64.4 ± 9.9) populations. There were significant differences in total IIFAS scores between women who intend to breastfeed (67.3 ± 8.3) and those who do not (51.6 ± 7.7), regardless of population region. The high value of the area under the curve (AUC) of the ROC (AUC = 0.92) demonstrates excellent ability of the IIFAS to predict intent to breastfeed. The internal consistency of the IIFAS was strong, with a Cronbach's alpha greater than .80 in the overall sample. CONCLUSION: The IIFAS examined in this provincial population provides a valid and reliable assessment of maternal attitudes toward infant feeding. This tool could be used to identify mothers less likely to breastfeed and to inform health promotion programs.


Assuntos
Atitude Frente a Saúde , Alimentação com Mamadeira/psicologia , Aleitamento Materno/psicologia , Mães/psicologia , Gravidez/psicologia , Inquéritos e Questionários , Adulto , Estudos Transversais , Feminino , Humanos , Intenção , Terra Nova e Labrador , Curva ROC , Reprodutibilidade dos Testes , População Rural , População Urbana
13.
J Chromatogr Sci ; 48(9): 733-41, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20875235

RESUMO

A new stability-indicating reversed-phase HPLC (RP-HPLC) method has been developed and validated for simultaneous assay of betamethasone dipropionate (BD) and chlorocresol and also for the estimation of BD related compounds in a pharmaceutical cream matrix. In addition, this newly developed RP-HPLC method was also demonstrated as suitable for a pharmaceutical ointment product that does not contain chlorocresol. The RP-HPLC method uses a Waters SymmetryShield RP18 analytical column (150 × 4.6 mm). Water (mobile phase A) and acetonitrile (mobile phase B) were used in the gradient elution with a flow rate of 1.5 mL/min and detection wavelength at 240 nm. A Waters XBridge Shield RP18 analytical column (150 × 4.6 mm) was identified as an alternate column. The limit of detection (LOD) and the limit of quantitation (LOQ) are 0.02 µg/mL and 0.05 µg/mL, respectively. The precision of the method for BD is less than 0.3% RSD, and the accuracy of BD ranged from 99.5% to 102.6%. The stability-indicating capability of this method has been demonstrated by analyzing aged samples of the product. This RP-HPLC method was successfully validated per ICH guidelines and proved to be suitable for routine quality control use.


Assuntos
Betametasona/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Cresóis/análise , Betametasona/análise , Betametasona/química , Cresóis/química , Estabilidade de Medicamentos , Modelos Lineares , Pomadas/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
Electrophoresis ; 28(11): 1752-61, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17476716

RESUMO

In this study, polymers of sodium 10-undecenoyl L-leucinate (SUL) and sodium undecenyl sulfate (SUS) as well as their copolymerized molecular micelles (CoPMMs) were applied in MEKC as pseudostationary phases to separate benzodiazepines and alkyl phenyl ketones. SDS, a common pseudostationary phase used in MEKC, was also used for comparison. The van't Hoff relationship was applied to compute the temperature dependence of the MEKC retention factors of the test solutes to estimate the enthalpy, entropy, and the Gibbs free energy. Nonlinear van't Hoff plots were obtained with the majority of benzodiazepines indicating that the thermodynamic parameters were temperature-dependent in all surfactant systems for these solutes. In contrast, all alkyl phenyl ketones resulted in linear van't Hoff plots.


Assuntos
Benzodiazepinas/química , Cromatografia Capilar Eletrocinética Micelar/métodos , Cetonas/química , Micelas , Acetofenonas/isolamento & purificação , Benzodiazepinas/isolamento & purificação , Butirofenonas/isolamento & purificação , Cetonas/isolamento & purificação , Propiofenonas/isolamento & purificação , Temperatura , Termodinâmica
15.
Electrophoresis ; 26(2): 415-25, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15657889

RESUMO

Sodium di(undecenyl) tartarate monomer (SDUT), a vesicle-forming amphiphilic compound possessing two hydrophilic carboxylate head groups and two hydrophobic undecenyl chains gemini surfactant, was prepared and polymerized to form a polymeric gemini surfactant (i.e., poly-SDUT). These anionic surfactant systems with carboxylate (SDUT and poly-SDUT) and sulfate (sodium dodecyl sulfate, SDS) head groups as well as mixed surfactant systems (SDS/SDUT, SDS/poly-SDUT, and SDUT/poly-SDUT) were then applied as novel pseudostationary phases in micellar electrokinetic chromatography (MEKC). The SDUT and poly-SDUT were characterized using various analytical techniques. Retention factors of 36 benzene derivatives were calculated in 20 mM phosphate buffer of each surfactant system. The retention factor values of the test solutes show that there are distinctive selectivity differences between the surfactant systems. Solute-pseudostationary phase interactions in MEKC were also examined by determining the free energy of transfer of the substituted functional groups from the aqueous buffer phase into the pseudostationary phase.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Tensoativos/química , Ânions , Derivados de Benzeno/isolamento & purificação , Ácidos Carboxílicos , Interações Hidrofóbicas e Hidrofílicas , Sulfatos , Termodinâmica
16.
Electrophoresis ; 24(24): 4209-20, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14679568

RESUMO

An achiral monomeric surfactant (sodium 10-undecenyl sulfate, SUS) and a chiral surfactant (sodium 10-undecenoyl L-leucinate, SUL) were synthesized and polymerized individually to form poly-SUS and poly-SUL. These surfactants were then copolymerized at various molar ratios to produce a variety of copolymerized surfactants (CoPSs), possessing both achiral (sulfate) and chiral (leucinate) head groups. The CoPSs, poly-SUS, poly-SUL, and sodium dodecyl sulfate were characterized using several analytical techniques. The aggregation numbers of the polymeric surfactants and the partial specific volumes were determined by the use of fluorescence quenching and density measurements, respectively. These polymeric surfactants were investigated as novel pseudostationary phases in micellar electrokinetic chromatography (MEKC) for the separation of chiral and achiral solutes. Solute hydrophobicity was found to have major influence on the MEKC retention of alkyl phenyl ketones. In contrast, hydrogen-bonding ability of benzodiazepines is the major factor that governs their retention, but hydrophobicity has an insignificant effect on MEKC retention of benzodiazepines.


Assuntos
Benzodiazepinas/química , Cromatografia Capilar Eletrocinética Micelar/métodos , Interações Hidrofóbicas e Hidrofílicas , Dodecilsulfato de Sódio/química , Tensoativos/química , Micelas , Estrutura Molecular
17.
Anal Chem ; 75(22): 6089-96, 2003 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-14615986

RESUMO

In this study, we report the use of ionic liquids as modifiers in the separation of achiral and chiral analytes in micellar electrokinetic chromatography. In this investigation, polymeric surfactants and ionic liquids were added to a low-conducting buffer solution. The polymeric surfactants used in this study were poly(sodium N-undecylelinic sulfate) and poly(sodium oleyl-l-leucylvalinate). The ionic liquids used in this study were chosen because of their high conductivity, hydrophobicity, and good solvating properties. Thus, it was expected that these ionic liquids would have the ability to assist in the separation of hydrophobic mixtures while maintaining adequate background current. Three analyte mixtures were separated using various buffer combinations of polymeric surfactant and ionic liquids. The ionic liquids were shown to improve the resolution and peak efficiency of the analytes while maintaining adequate background current.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Cetonas/isolamento & purificação , Fenóis/isolamento & purificação , Tensoativos , Íons/química , Cetonas/química , Estrutura Molecular , Fenóis/química , Estereoisomerismo , Fatores de Tempo
18.
Electrophoresis ; 25(4-5): 758-65, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14981705

RESUMO

One disadvantage of amino acid-based chiral selectors for micellar electrokinetic chromatography (MEKC) is that either they have very low solubility or are insoluble at acidic pHs. In order to increase solubilities at lower pHs, we have synthesized a highly water-soluble achiral surfactant and copolymerized it with an amino acid-based chiral surfactant. These two surfactants were polymerized either separately or at various molar rations of binary solutions, yielding pure molecular or copolymerized surfactant (CoPS), respectively. All surfactants were characterized by use of several analytical techniques prior to using them as novel pseudostationary phases in MEKC. The chromatographic performance of the CoPS in MEKC was tested with chiral and achiral analytes. The highly soluble sulfate head group significantly increased the solubility of amino acid-based CoPS over a wide range of pH. Three chiral binaphthyl derivatives were tested and each surfactant system was found to have different selectivity.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Polímeros/síntese química , Tensoativos/síntese química , Aminoácidos/química , Ânions , Concentração de Íons de Hidrogênio , Naftóis/química , Naftóis/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/química , Solubilidade , Estereoisomerismo , Tempo
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