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1.
Int J Biol Macromol ; 121: 104-112, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30291928

RESUMO

The novel silane crosslinked (TEOS) hydrogels based on eco-friendly biodegradable chitosan/guargum were prepared by blending with PEG to develop pH sensitive hydrogels (CGP) and achieved its hydrophilicity and target specificity for controlled release of drug. The crosslinker amount was varied to analyze its effect on the hydrogel properties and were characterized using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution) and in-vitro release of cephradine (CED). FTIR confirmed the presence of characteristic peaks and crosslinking between the components while SEM images showed the formation of clear micro- and macro-pores. The swelling behavior in water showed that compared to the controlled hydrogel, the crosslinked hydrogels revealed more swelling but a decrease in swelling with further increase in the amount of crosslinker was observed. The hydrogels showed low swelling at basic and neutral pH while maximum swelling was observed at acidic pH. This pH response made these hydrogels an ideal candidate for injectable controlled release. The CED was loaded on hydrogels and its release mechanism was studied in PBS, SGF and SIF which revealed that out of all hydrogels (CGP100, CGP150, CGP200 and CGP250), CGP100 has shown CED release of 85% in 130 min in PBS and 82.4% in SIF.


Assuntos
Cefradina/química , Quitosana/química , Portadores de Fármacos/química , Galactanos/química , Hidrogéis/química , Mananas/química , Gomas Vegetais/química , Tampões (Química) , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Concentração Osmolar , Água/química
2.
Ecotoxicol Environ Saf ; 159: 56-62, 2018 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-29730409

RESUMO

Our research investigated the hormesis effect of cefradine on the specific growth rates (µ) of single-celled algae (Chlamydomonas reinhardtii) from aqueous solutions. We found the specific growth rate of C. reinhardtii slightly increased with cefradine concentrations within the range 0.5-10 mg/L. Effects of algae density, initial solution pH, and temperature on the adsorption batch assays were investigated. The optimum conditions for cefradine adsorption occurred at a density of 5 × 106 algae cells/mL, a solution pH of 7.0, and a temperature of 25.0 °C. A Box-Behnken design was employed to evaluate correlations between influential factors and cefradine adsorption. The results showed a significant interaction between algae density and temperature. The maximum removal rate could reach 50.13% under the optimal conditions. Additionally, the adsorption mechanisms were explored through Langmuir and Freundlich isotherm equations, adsorption kinetics, and thermodynamics. The results suggested that the adsorption process was monolayer, spontaneous, and endothermic with an increase in randomness at the algae-solution interface, which followed a pseudo-second-order model. All the data indicated that the alga performed a better removal capacity in the antibiotic-containing wastewater treatment process. This study lays the groundwork for a better understanding of the interaction mechanism between cefradine and Chlamydomonas reinhardtii in water solutions under dark condition.


Assuntos
Antibacterianos/química , Cefradina/química , Chlamydomonas reinhardtii/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Antibacterianos/análise , Antibacterianos/farmacologia , Cefradina/análise , Cefradina/farmacologia , Chlamydomonas reinhardtii/efeitos dos fármacos , Chlamydomonas reinhardtii/genética , Concentração de Íons de Hidrogênio , Cinética , Soluções , Temperatura Ambiente , Termodinâmica , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/farmacologia , Purificação da Água/métodos
3.
Rapid Commun Mass Spectrom ; 32(7): 576-582, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29397004

RESUMO

RATIONALE: Cephalosporins (e.g. cephalexin, cefradine) are a major group of widely used ß-lactam antibiotics. Hydrolysis of the ß-lactam ring is an important reaction (often undesired) which leads to deactivation of ß-lactams. To the best of our knowledge there is no electrospray ionization mass spectrometry (ESI-MS) data reported concerning the products of hydrolysis of cephalosporins. METHODS: The hydrolysis of cephalexin and cefradine was performed in aqueous NaOH solutions. After the process the solutions were analyzed by high-performance liquid chromatography (HPLC)/ESI-MS. The elemental compositions of the ions discussed were confirmed by the accurate mass measurements on a quadrupole time-of-flight (QTOF) mass spectrometer. RESULTS: Unexpectedly, complexes between the hydrolysis products of cephalexin and cefradine (CFLh and CFRh ) and iron cation were detected upon HPLC/ESI-MS analysis, namely the ions [(CFLh -H)2 +Fe]+ and [(CFRh -H)2 +Fe]+ , although iron was not added to the analyzed solutions or to the mobile phase. These ions were found to be very stable in the gas phase. CONCLUSIONS: The detection of the complexes between the hydrolysis products of cephalosporins and iron may have a positive impact on the sensitivity and specificity of HPLC/ESI-MS analyses of the hydrolysis products of some cephalosporins.


Assuntos
Cefalexina/análise , Cefradina/análise , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Ferro/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Cefalexina/química , Cefradina/química , Hidrólise , Compostos de Ferro/química , Hidróxido de Sódio
4.
Chem Commun (Camb) ; 53(54): 7604-7607, 2017 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-28639649

RESUMO

Computational enzyme design exhibits excellent performance for identifying potential scaffolds from structural databases and creating new enzymatic catalysts from naught. Using the active site-matching algorithm ProdaMatch, we identified a new scaffold cocaine esterase from Rhodococcus sp. that showed modest activity (kcat/Km = 0.018 M-1 s-1) towards the hydrolysis of ß-lactam antibiotic cephradine. The identified cocaine esterase scaffold afforded low sequence identity (<30%) with the known ß-lactam synthases, such as penicillin G acylase or α-amino acid ester hydrolase, and was able to catalyze the condensation reaction between d-dihydrophenylglycine methyl ester and 7-aminodesacetoxycephalosporanic acid to produce cephradine via a kinetically controlled synthesis. By virtue of the computational enzyme design protocol, hundreds of sequences were predicted in the cocaine esterase scaffold to promote the catalytic activity towards the hydrolytic reaction of cephradine. Moreover, a single mutant (F261T) was experimentally confirmed to have improved the catalytic efficiency by ten times (kcat/Km = 0.193 M-1 s-1), indicating that the novel scaffold cocaine esterase may be potentially redesigned to become an industrially useful cephradine synthase.


Assuntos
Algoritmos , Hidrolases de Éster Carboxílico/química , Biologia Computacional , Bases de Dados de Proteínas , Biocatálise , Hidrolases de Éster Carboxílico/metabolismo , Domínio Catalítico , Cefradina/química , Cefradina/metabolismo , Modelos Moleculares , Estrutura Molecular , Conformação Proteica
5.
Nanoscale ; 7(47): 19985-20002, 2015 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-26564987

RESUMO

Herein, we report a detailed experimental study supported by DFT calculations to understand the mechanism behind the synthesis of cefradine (CFD--an antibiotic) labeled gold nanoparticles (Au NPs) by employing CFD as both a mild reducing and capping agent. The analysis of the effect of growth conditions reveals that a higher concentration of HAuCl4 results in the formation of an increasing fraction of anisotropic structures, higher temperature leads to the formation of quasi-spherical particles instead of anisotropic ones, and larger pH leads to the formation of much smaller particles. The cyclic voltammetry (CV) results show that when the pH of the reaction medium increases from 4 to 6, the reduction potential of CFD increases which leads to the synthesis of nanoparticles (in a pH 4 reaction) to quantum clusters (in a pH 6 reaction). The MALDI-TOF mass spectrometry results of supernatant of the pH 6 reaction indicate the formation of [Au8(CFD)2S6] QCs which show fluorescence at ca. 432 nm with a Stokes shift of ca. 95 nm. The blue luminescence from Au8 QCs was applied for sensing of Hg(2+) ions on the basis of an aggregation-induced fluorescence quenching mechanism and offers good selectivity and a high sensitivity with a limit of detection ca. 2 nM which is lower than the detection requirement of 10 nM by the U.S. EPA and 30 nM by WHO for drinking water. We have also applied the sensing probe to detect Hg(2+) ions in bacterial samples. Further, we have investigated the antibacterial property of as-synthesized Au NPs using MIC, growth curve and cell survival assay. The results show that Au NPs could reduce the cell survival very efficiently rather than the cell growth in comparison to the antibiotic itself. The scanning electron microscopy study shows the degradation and blebbing of the bacterial cell wall upon exposure with Au NPs which was further supported by fluorescence microscopy results. These Au NPs did not show reactive oxygen species generation. We believe that the bacterial cytotoxicity is due to the direct contact of the Au NPs with bacterial cells.


Assuntos
Antibacterianos/química , Ouro/química , Mercúrio/química , Nanopartículas Metálicas/química , Acetatos/química , Anisotropia , Proliferação de Células , Sobrevivência Celular , Cefradina/química , Concentração de Íons de Hidrogênio , Íons , Luminescência , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Nanotecnologia/métodos , Estresse Oxidativo , Pontos Quânticos , Espécies Reativas de Oxigênio/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectroscopia de Luz Próxima ao Infravermelho , Eletricidade Estática
6.
Chemosphere ; 134: 452-8, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26001938

RESUMO

The direct and indirect photodegradation of six cephalosporins was predicted using a photochemical model, on the basis of literature values of photochemical reactivity. Environmental photodegradation would be important in surface water bodies with depth ⩽ 2-3m, and/or in deeper waters with low values of the dissolved organic carbon (DOC ⩽ 1 mg C L(-1)). The half-life times would range from a few days to a couple of weeks in summertime. In deeper and higher-DOC waters and/or in different seasons, hydrolysis could prevail over photodegradation. The direct photolysis of cephalosporins is environmentally concerning because it is known to produce toxic intermediates. It would be a major pathway for cefazolin, an important one for amoxicillin and cefotaxime and, at pH<6.5, for cefapirin as well. In contrast, direct photolysis would be negligible for cefradine and cefalexin. The DOC values would influence the fraction of photodegradation accounted for by direct photolysis in shallow water, to a different extent depending on the role of sensitisation by the triplet states of chromophoric dissolved organic matter.


Assuntos
Cefalosporinas/química , Fotólise , Poluentes Químicos da Água/análise , Amoxicilina/química , Carbono/química , Cefazolina/química , Cefalexina/química , Cefradina/química , Água Doce/química , Meia-Vida , Concentração de Íons de Hidrogênio , Hidrólise , Modelos Químicos , Modelos Teóricos
7.
Environ Sci Technol ; 49(3): 1552-8, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25590945

RESUMO

Understanding hydrolysis pathways and kinetics of many antibiotics that have multiple hydrolyzable functional groups is important for their fate assessment. However, experimental determination of hydrolysis encounters difficulties due to time and cost restraint. We employed the density functional theory and transition state theory to predict the hydrolysis pathways and kinetics of cephradine, a model of cephalosporin with two hydrolyzable groups, two ionization states, two isomers and two nucleophilic attack directions. Results showed that the hydrolysis of cephradine at pH = 8.0 proceeds via opening of the ß-lactam ring followed by intramolecular amidation. The predicted rate constants at different pH conditions are of the same order of magnitude as the experimental values, and the predicted products are confirmed by experiment. This study identified a catalytic role of the carboxyl group in the hydrolysis, and implies that the carboxyl group also plays a catalytic role in the hydrolysis of other cephalosporin and penicillin antibiotics. This is a first attempt to quantum chemically predict hydrolysis of an antibiotic with complex pathways, and indicates that to predict hydrolysis products under the environmental pH conditions, the variation of the rate constants for different pathways with pH should be evaluated.


Assuntos
Antibacterianos/química , Cefradina/química , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Hidrólise , Cinética
8.
J Biomater Sci Polym Ed ; 25(3): 257-68, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24160558

RESUMO

This research described a novel composite electrospun nanofibers, which were consisted of MPEG-b-PLA micelles, chitosan, and PEO, realizing controlled release of both hydrophobic and hydrophilic drugs. 5-FU and Cefradine used as model drugs were successfully loaded in the nanofibers. The in vitro studies showed there was a low initial burst release of 5-FU from micelles-loaded nanofibers, and the final release proportion was about 91.4% after continually releasing for 109 h. In vitro cytotoxicity studies revealed that 5-FU-loaded nanofibers restrained HepG-2 cells efficiently, and the cell viability was 45.9% after three days of cultivation in solutions containing micelles-loaded nanofibers with 21.6 µg 5-FU. All results suggested that micelles-loaded nanofibers with two kinds of drugs can be used as an effective controlled drug delivery vehicle and may have a bright future in cancer chemotherapy or clinical treatments.


Assuntos
Portadores de Fármacos/química , Micelas , Nanofibras/química , Nanotecnologia , Poliésteres/química , Polietilenoglicóis/química , Cefradina/química , Preparações de Ação Retardada , Fluoruracila/química , Células Hep G2 , Humanos , Interações Hidrofóbicas e Hidrofílicas
9.
Acta Crystallogr C ; 69(Pt 11): 1229-33, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24192164

RESUMO

The crystal structure of cefradine dihydrate, C16H19N3O4S·2H2O, is considered in the pharmaceutical sciences to be the epitome of an isolated-site hydrate. The structure from single-crystal X-ray data was described in 1976, but atomic coordinates were not published. The atomic coordinates are determined here by combining the information available from the published single-crystal data with a dispersion-corrected density functional theory (DFT-D) method that has been validated to reproduce molecular crystal structures very accurately. Additional proof for the correctness of the structure comes from comparison with cefaclor dihydrate, C15H14ClN3O4S·2H2O, which is isomorphous and for which more complete single-crystal data are available. H-atom positions have not previously been published for either compound. The DFT-D calculations confirm that both cefradine and cefaclor are present in the zwitterionic form in the two dihydrate structures. A potential ambiguity concerning the orientation of the cyclohexadienyl ring in cefradine dihydrate is also clarified, and on the basis of the calculated energies it is shown that disorder should not be expected at room temperature. The DFT-D methods can be applied to recover full structural data in cases where only partial information is available, and where it may not be possible or desirable to obtain new experimental data.


Assuntos
Cefaclor/química , Cefradina/química , Cicloexenos/química , Cristalografia por Raios X , Ligações de Hidrogênio , Teoria Quântica
10.
J Biomater Sci Polym Ed ; 24(8): 972-85, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23647252

RESUMO

Novel biocompatible poly(lactide-co-glycolide) (PLGA) nanofiber mats with favorable biocompatibility and good mechanical strength were prepared, which could serve as an innovative type of tissue engineering scaffold or an ideal controllable drug delivery system. Both hydrophobic and hydrophilic drugs, Cefradine and 5-fluorouracil were successfully loaded into PLGA nanofiber mats by emulsion electrospinning. The natural bioactive protein gelatin (GE) was incorporated into the nanofiber mats to improve the surface properties of the materials for cell adhesion. Nanofibrous scaffolds were characterized by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, contact angle and tensile measurements. Emulsion electrospun fibers with GE had perfect hydrophilic and good mechanical property. The in vitro release test showed thedrugs released from emulsion electrospun fibers, which achieved lower burst release. The cells cytotoxicity experiment indicated that emulsion electrospun fibers were less toxic and tended to promote fibroblasts cells attachment and proliferation, which implied that the electrospun fibers had promising potential application in tissue engineering or drug delivery.


Assuntos
Materiais Biocompatíveis/química , Gelatina/química , Ácido Láctico/química , Nanofibras/química , Ácido Poliglicólico/química , Animais , Células Cultivadas , Cefradina/administração & dosagem , Cefradina/química , Sistemas de Liberação de Medicamentos , Emulsões , Fluoruracila/administração & dosagem , Fluoruracila/química , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
11.
Talanta ; 83(2): 312-9, 2010 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-21111139

RESUMO

The luminol-bovine serum albumin chemiluminescence system was proposed for the first time. It was found that the hydrophilic luminol bound to the hydrophilic domain at Trp(134) of BSA with accelerating the electrons transferring rate of excited 3-aminophthalate, which led to the enhancement CL intensity of luminol at 425 nm. The increment of chemiluminescence intensity was proportional to the concentrations of bovine serum albumin from 5.0 × 10(-11) to 1.0 × 10(-8)mol L(-1) with the linear equation of ΔI=7.47 C(BSA)+4.89 (R(2)=0.9950). Based on the remarkable quenching effect of cephalosporin on the luminol-bovine serum albumin chemiluminescence system, the interaction of bovine serum albumin-cephalosporin was studied by flow injection-chemiluminescence method. A valuable model for studying the interaction of bovine serum albumin-cephalosporin was constructed and the formula lg[(I(0)-I)/I]=lg K(D)+n lg[D] was obtained. The binding parameters calculated by the model did agree very well with the results obtained by fluorescence quenching method. The major binding force of bovine serum albumin with cephalosporins was the hydrophobic effect. The binding ability of cephalosporin analogues to bovine serum albumin followed the pattern: cefoperazone, ceftriaxone and cefotaxime>cefuroxime and cefaclor>cefadroxil, cefradine and cefazolin, which was close to the order of their antibacterial ability. Using flow injection chemiluminescence method also obtained the stoichiometric ratio, the average of association constant K(P) and dissociation degree α of luminol-bovine serum albumin were 1:1, 1.12 × 10(7)L mol(-1) and 0.086, respectively.


Assuntos
Cefalosporinas/química , Luminescência , Medições Luminescentes/métodos , Soroalbumina Bovina/química , Animais , Antibacterianos/química , Bovinos , Cefaclor/química , Cefadroxila/química , Cefazolina/química , Cefoperazona/química , Cefotaxima/química , Ceftriaxona/química , Cefuroxima/química , Cefradina/química , Ácidos Ftálicos/química , Termodinâmica , Triptofano/química
12.
Appl Spectrosc ; 64(10): 1154-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20925986

RESUMO

A new chemiluminescence reaction, the luminol-Cu(2+) reaction, was investigated for the determination of thirteen (13) cephalosporin antibiotics, namely cefalexin, cefadroxil, cefradine, cefazolin sodium, cefaclor, cefuroxime axetil, cefotaxime sodium, cefoperazone sodium, ceftriaxone sodium, ceftazidime, cefetamet pivoxil hydrochloride, cefixime, and cefpodoxime. It was found that, without adding any special oxidant, strong chemiluminescent (CL) signal could be produced from the reaction of the alkaline luminol with the above-mentioned antibiotics in the presence of Cu(2+). The experimental conditions for the reaction were carefully optimized with flow-injection mode. The detection limits are 0.3 ng/mL cefalexin, 3 ng/mL cefadroxil, 0.3 ng/mL cefradine, 0.02 µg/mL cefazolin sodium, 0.8 ng/mL cefaclor, 0.02 µg/mL cefuroxime axetil, 5 ng/mL cefotaxime sodium, 0.02 µg/mL cefoperazone sodium, 0.8 ng/mL ceftriaxone sodium, 1 ng/mL ceftazidime, 0.08 ng/mL cefetamet pivoxil hydrochloride, 0.8 ng/mL cefixime, and 2 ng/mL cefpodoxime. The proposed method was validated by direct application to commercial formulations and spiked milk samples containing cefradine. A possible reaction mechanism is also discussed.


Assuntos
Cefalosporinas/análise , Cobre/química , Substâncias Luminescentes/química , Medições Luminescentes/métodos , Luminol/química , Espectrometria de Fluorescência/métodos , Animais , Cefalosporinas/química , Cefradina/análise , Cefradina/química , Análise de Injeção de Fluxo/métodos , Modelos Lineares , Leite/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
Chemosphere ; 80(11): 1399-405, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20579689

RESUMO

Cephalosporins are widely used veterinary and human antibiotics, but their environmental fate and impacts are still unclear. We studied degradation of four cephalosporins (cefradine, cefuroxime, ceftriaxone, and cefepime) from each generation in the surface water and sediment of Lake Xuanwu, China. The four cephalosporins degraded abiotically in the surface water in the dark with half-lives of 2.7-18.7d, which were almost the same as that in sterilized surface water. Under exposure to simulated sunlight, the half-lives of the cephalosporins decreased significantly to 2.2-5.0d, with the maximal decrease for ceftriaxone from 18.7d in the dark to 4.1d under the light exposure. Effects of dissolved organic matter (DOM) and nitrate on photodegradation of the cephalosporins were compound-specific. While DOM (5 mg L(-1)) stimulated the photodegradation of only cefradine (by 9%) and cefepime (by 34%), nitrate (10 microM) had effects only on cefepime (stimulation by 13%). Elimination rates of the cephalosporins in oxic sediment (half-lives of 0.8-3.1d) were higher than in anoxic sediment (half-lives of 1.1-4.1d), mainly attributed to biodegradation. The data indicate that abiotic hydrolysis (for cefradine, cefuroxime, and cefepime) and direct photolysis (for ceftriaxone) were the primary processes for elimination of the cephalosporins in the surface water of the lake, whereas biodegradation was responsible for the elimination of the cephalosporins in the sediment. Further studies are needed on chemical structure, toxicity, and persistence of transformation products of the cephalosporins in the environment.


Assuntos
Antibacterianos/metabolismo , Cefalosporinas/metabolismo , Água Doce/química , Sedimentos Geológicos/química , Poluentes Químicos da Água/metabolismo , Aerobiose , Antibacterianos/análise , Antibacterianos/química , Biodegradação Ambiental , Cefepima , Ceftriaxona/análise , Ceftriaxona/química , Ceftriaxona/metabolismo , Cefuroxima/análise , Cefuroxima/química , Cefuroxima/metabolismo , Cefalosporinas/análise , Cefalosporinas/química , Cefradina/análise , Cefradina/química , Cefradina/metabolismo , Água Doce/microbiologia , Sedimentos Geológicos/microbiologia , Nitratos/química , Oxigênio/química , Fotólise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
14.
Talanta ; 81(1-2): 698-702, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20188984

RESUMO

The aggregation of gold nanoparticles (GNPs) capped with nonionic fluorosurfactant (FSN) could be induced rapidly and selectively by cephradine degradation products, but not by cephradine and other excipients in pharmaceutical formulations. A new detection method for cephradine has been developed based on the cephradine degradation products-induced aggregation of the GNPs. The present approach offers various advantages, such as simplicity and high selectivity. Under optimum conditions, the lowest detectable concentration of cephradine through this approach (S/N=3) is 0.8 microg mL(-1). The calibration curve was linear over the range of 2.0-10.0 microg mL(-1) for the detection of cephradine. The recoveries of cephradine were found to fall in the range between 97% and 105%. We have validated the applicability of our method through the analyses of cephradine in pharmaceutical formulations. Good agreements were obtained for the determination of cephradine between the present approach and official method.


Assuntos
Cefradina/análise , Ouro/química , Halogenação , Nanopartículas Metálicas/química , Tensoativos/química , Cefradina/química , Química Farmacêutica , Colorimetria , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Concentração Osmolar , Reprodutibilidade dos Testes , Temperatura Ambiente
15.
Yao Xue Xue Bao ; 45(11): 1421-6, 2010 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-21361043

RESUMO

Construction of a successful near infrared analysis model is a complex task. It spends a lot of manpower and material resources, and is restricted by sample collection and model optimization. So it is important to study on the extended application of the existing near infrared (NIR) models. In this paper, cephradine capsules universal quantitative model was used as an example to study on the feasibility of its extended application. Slope/bias correction and piecewise direct standardization correction methods were used to make the universal model to fit to predict the intermediates in manufacturing processes of cephradine capsules, such as the content of powder blend or granules. The results showed that the corrected NIR universal quantitative model can be used for process control although the results of the model correction by slope/bias or piecewise direct standardization were not as good as that of model updating. And it also indicated that the model corrected by slope/bias is better than that by piecewise direct standardization. Model correction provided a new application for NIR universal models in process control.


Assuntos
Cefradina/química , Modelos Químicos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Antibacterianos/química , Calibragem/normas , Estudos de Viabilidade
16.
J Fluoresc ; 19(5): 801-8, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19343485

RESUMO

It was first found that the intrinsic fluorescence of lysozyme at 340 nm can be quenched by cephalosporin analogues through the static quenching and non-radiative energy transferring procedure. In the acetate buffer solution with pH 7.0 and 298 K, the quenching fluorescence intensity was in a good linearity over the concentration of drugs in the range of 1-100 micromol L(-1), 0.1-100 micromol L(-1), 0.5-100 micromol L(-1) and 0.05-100 micromol L(-1) for cefradine, cefuroxime, cefotaxime and ceftriaxone, respectively. The quenching ability or the binding ability of the studied drugs followed the pattern: ceftriaxone > cefotaxime > cefuroxime > cefradine, which was close to the order of their antibacterial ability. The binding parameters including the association constant and the number of binding potential point were calculated at different temperatures (288, 298 and 308 K), and thermodynamic parameters DeltaH degrees, DeltaS degrees and DeltaG degrees were given. The binding mode of lysozyme with cephalosporins showed that the hydrophobic effect might play a major role. The binding distance between cephalosporin and tryptophan residue in lysozyme was obtained. The results provided the quantitative information for the binding of cephalosporin to lysozyme, and it was suggested that the drugs probably bound to the active site near Trp62 in lysozyme.


Assuntos
Cefotaxima/química , Ceftriaxona/química , Cefuroxima/química , Cefradina/química , Muramidase/química , Sítios de Ligação , Fluorescência , Muramidase/metabolismo , Espectrometria de Fluorescência , Temperatura Ambiente , Termodinâmica
17.
J Biomed Mater Res B Appl Biomater ; 84(2): 486-92, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17635037

RESUMO

Incorporation of antibiotics in the apatite coatings on titanium surface is an effective step for surgical infections of titanium implant. In this work, antibiotics cephradine and traditional Chinese medicine salviae miltlorrhizae (SM) were incorporated in the simulated body fluid (SBF). The apatite coatings were coprecipitated with cephradine and SM by a biomimetic method. The research showed that in the biomimetic coprecipitation process cephradine containing carboxylic groups were beneficial to the apatite coprecipitation. X-ray diffraction patterns showed that cephradine had a positive effect on the crystal growth in terms of cystallinity. And also in the Fourier transformed infrared spectra, the organic groups corresponded with cephradine were also observed. However, little apatite formed on the titanium immersed in SBF with SM. Probably, SM was more absorbed on the surface when calcium and phosphate ions precipitated.


Assuntos
Apatitas/química , Materiais Biomiméticos/química , Biomimética , Cefradina/química , Materiais Revestidos Biocompatíveis/química , Medicamentos de Ervas Chinesas/química , Titânio , Precipitação Química , Medicina Tradicional Chinesa
18.
Pak J Pharm Sci ; 20(3): 179-84, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17545100

RESUMO

The present work comprises of interaction studies of cephradine with antacids. Cephradine is included among the first generation cephalosporin, which is active against a wide range of Gram positive and Gram-negative bacteria including penicillinase-producing staphylococci. Since the presence of complexing ligand may affect the bioavailability of a drug in blood or tissues, therefore, in order to study the probable interaction of cephradine with antacids all the reaction conditions were simulated to natural environments. Antacids are commonly used in patients complaining of GI irritations. The behavior of cephradine in presence of seven antacids i.e., simethicone, magaldrate, magnesium carbonate, magnesium hydroxide, magnesium trisilicate, sodium bicarbonate and aluminium hydroxide was studied by using standard dissolution apparatus. Cephradine was monitored both by UV and by high performance liquid chromatography. The results revealed that antacids containing polyvalent cations retarded the in vitro availability of cephradine. Moreover, these studies indicated that cephradine was strongly adsorbed on antacids; magnesium trisilicate and simeco tablets (powdered) exhibited relatively higher adsorption capacities.


Assuntos
Antiácidos/química , Antibacterianos/química , Cefalosporinas/química , Cefradina/química , Adsorção , Cromatografia Líquida de Alta Pressão , Interações de Medicamentos , Espectrofotometria Ultravioleta
19.
J Nanosci Nanotechnol ; 6(9-10): 3210-4, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17048538

RESUMO

A novel controlled drug delivery system was fabricated by coating chitosan/PAA multilayer onto magnetic hollow spheres via a "Layer-by-Layer" (LBL) assembly approach. Cefradine was used as a model drug to evaluate the drug release characteristics of this core-shell hollow structure and the results show that it exhibits a sustained release of the drug and the release rate can be regulated by the pH environment of release medium. It is believed that this core-shell hollow structure, which combines the advantage of controlled delivery as well as magnetic targeting, has commendable potential in drug delivery therapeutics.


Assuntos
Resinas Acrílicas/química , Cefradina/química , Quitosana/química , Cristalização/métodos , Preparações de Ação Retardada/química , Portadores de Fármacos/química , Magnetismo/uso terapêutico , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Antibacterianos/química , Cefradina/administração & dosagem , Difusão , Eletrólitos/química , Microesferas , Tamanho da Partícula
20.
Arch Pharm Res ; 29(2): 178-82, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16526284

RESUMO

Four crystal forms of cephradine were isolated by recrystallization and characterized by powder X-ray diffractometry, differential scanning calorimetry, and thermogravimetric analysis. The dissolution patterns of four crystal forms of cephradine were studied in water at 37 +/- 0.5 degrees C, 90 rpm for 120 min. The amount dissolved at 120 min was highest for Form I (100%), followed by Form 3 (98.9%), Form 4 (77.83%), and Form 2 (75.55%). After storage for two months at 0% RH (silica gel, 20 degrees C), 52% RH (saturated solution of Na2Cr2O7 x 2H2O/ 20 degrees C), and 95% RH (saturated solution of Na2HPO4/20 degrees C), none of the crystal forms showed transformation.


Assuntos
Antibacterianos/química , Cefradina/química , Varredura Diferencial de Calorimetria , Cristalização , Estabilidade de Medicamentos , Solubilidade , Termogravimetria , Fatores de Tempo , Água/química , Difração de Raios X
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