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1.
CdS nanoparticles (CdS NPs) of different sizes were synthesized by the citrate reduction method. It was found that CdS NPs could enhance the chemiluminescence (CL) of the luminol‐potassium ferricyanide system and baicalin could inhibit CdS NPs‐enhanced luminol‐potassium ferricyanide CL signals in alkaline solution. Based on this inhibition, a flow‐injection CL method was established for determination of baicalin in pharmaceutical preparations and human urine samples. Under optimized conditions, the linear range for determination of baicalin was 5.0 x 10?6 to 1.0 x 10?3 g/L. The detection limit at a signal‐to‐noise ratio of 3 was 1.7 x 10 ?6 g/L. CL spectra, UV‐visible spectra and transmission electron microscopy (TEM) were used to investigate the CL mechanism. The method described is simple, selective and obviates the need of extensive sample pretreatment. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
2.
A simple and sensitive spectrofluorimetric method was developed for the determination of Ribavirin in pharmaceutical formulations. The proposed method was based on the fluorescence spectral behaviour of Ribavirin in a sodium dodecyl sulfate (SDS) micellar system. In an aqueous acetate buffer solution of pH 4.0, the fluorescence intensity of Ribavirin was significantly enhanced by about 217% in the presence of SDS. Fluorescence intensity was measured at 396 nm after excitation at 270 nm for Ribavirin. The fluorescence‐concentration plot was rectilinear over the range of 0.01‐3.0 µg/mL for Ribavirin with a lower detection limit of 5.02 x 10‐3 µg/mL. The method was successfully applied to the analysis of the drug in its commercial capsules. Results were in good agreement with those obtained with the official method. The application of the proposed method was extended to stability studies of Ribavirin after exposure to different forced degradation conditions such as acidic, alkaline, photo and oxidative conditions according to ICH guidelines. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
A simple, sensitive and selective spectrofluorimetric method has been developed for the determination of tobramycin (TOB) in human serum and pharmaceutical preparations. The method is based on the reaction between the primary amino group of TOB and fluorescamine in borate buffer, pH 8.5, to give a highly fluorescent derivative which is measured at 469 nm after excitation at 388 nm. The fluorescence intensity was directly proportional to the concentration over the range 300–1500 ng/mL, with a limit of detection of 65 ng/mL and limit of quantitation of 215 ng/mL. All variables were investigated to optimize the reaction conditions. The method was validated according to International Conference on Harmonization guidelines in terms of specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. Good recoveries were obtained ranging from 97.4 to 100.64%, indicating that no interference was observed from concomitants usually present in pharmaceutical dosage forms. The method was successfully, applied for the analysis of the drug substance in its pharmaceutical preparations and spiked serum samples. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
4.
Simple and rapid synchronous fluorometric methods were adopted and validated for the simultaneous analysis of a binary mixture of diphenhydramine (DIP) and ibuprofen (IBU) ( Mix I) or DIP and phenylephrine (PHE) (Mix II) in their co‐formulated pharmaceuticals without prior separation. Analysis of Mix I is based on the measurement of the peak amplitudes (D1) of synchronous fluorescence intensities at 265.1 nm for DIP and 260 nm for IBU. The relationship between the concentration and the amplitude of the first‐derivative synchronous fluorescence spectra showed good linearity over the concentration ranges 0.50–10.00 μg ml?1 and 0.50–7.90 μg ml?1 for DIP and IBU, respectively. Analysis of Mix II was based on measurement of the peak amplitude (D1) synchronous fluorescence intensities at 230 nm for DIP and at 253.9 nm for PHE. Moreover, for Mix II, the peak amplitude (D2) synchronous fluorescence intensities were measured at 227.9 nm for DIP and at 264.9 nm for PHE. Calibration plots were rectilinear over the concentration range 0.30–3.50 μg ml?1 and 0.03–0.75 μg ml?1 for DIP and PHE, respectively. The proposed methods were successfully applied to determine the studied compounds in pure form and in pharmaceutical preparations. 相似文献
5.
A simple chemiluminescence (CL) method using flow injection has been developed for the determination of clindamycin, based on the inhibitory effect of clindamycin on the CL generated from the luminol-K(3)Fe(CN)(6) system in alkaline medium. It was found that the decrement of CL intensity was linear with the logarithm of clindamycin concentration over the range 0.7-1000 ng/mL. The detection limit was 0.2 ng/mL with a relative standard deviation (RSD) of <5.0% (n = 7). At a flow rate of 3.0 mL/min, a complete analytical process could be performed within 0.5 min, including sampling and washing. The proposed procedure was applied successfully to the determination of clindamycin in pharmaceutical preparations and human urine without pretreatment. 相似文献
6.
A highly sensitive and simple spectrofluorimetric method was developed for the determination of loratadine (LRT) and desloratadine (DSL) in their pharmaceutical formulations. The proposed method is based on investigation of the fluorescence spectral behaviour of LRT and DSL in a sodium dodecyl sulphate (SDS) micellar system. In aqueous solution of acetate buffer of pH 4.5, the fluorescence intensities of both LRT and DSL were greatly enhanced (240%) in the presence of SDS. The fluorescence intensity was measured at 438 nm after excitation at 290 nm for both drugs. The fluorescence–concentration plots were rectilinear over the range 0.05–2.0 µg/mL for both LRT and DSL, with lower detection limits of 5.13 × 10?3 and 6.35 × 10?3 µg/mL for LRT and DSL, respectively. The method was successfully applied to the analysis of the two drugs in their commercial tablets, capsules and syrups, and the results were in good agreement with those obtained with the official or comparison methods. The proposed method is specific for the determination of LRT in the presence of other co‐formulated drugs, such as pseudoephedrine. The application of the proposed method was extended to stability studies of LRT and DSL after exposure to different forced degradation conditions, such as acidic, alkaline and oxidative conditions, according to ICH guidelines. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
A simple, highly sensitive and validated spectrofluorimetric method was applied in the determination of clonazepam (CLZ). The method is based on reduction of the nitro group of clonazepam with zinc/CaCl2, and the product is then reacted with 2‐cyanoacetamide (2‐CNA) in the presence of ammonia (25%) yielding a highly fluorescent product. The produced fluorophore exhibits strong fluorescence intensity at ?em = 383 nm after excitation at ?ex = 333 nm. The method was rectilinear over a concentration range of 0.1–0.5 ng/mL with a limit of detection (LOD) of 0.0057 ng/mL and a limit of quantification (LOQ) of 0.017 ng/mL. The method was fully validated and successfully applied to the determination of CLZ in its tablets with a mean percentage recovery of 100.10 ± 0.75%. Method validation according to ICH Guidelines was evaluated. Statistical analysis of the results obtained using the proposed method was successfully compared with those obtained using a reference method, and there was no significance difference between the two methods in terms of accuracy and precision. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
8.
A responsive spectrofluorometric method was developed for the determination of sitagliptin phosphate using l -tyrosine as a fluorescence probe. The fluorescence intensity of l -tyrosine was quenched with sitagliptin phosphate. The fluorescence intensity was recorded at 307 nm using a 272 nm excitation wavelength. The calibration plot between fluorescence intensity and the concentration of drug was linear in the range of 0.1 to 2.0 mM with a good correlation value of 0.997. The limit of detection and quantification were established to be 3.7 × 10−4 and 1.23 × 10−3 mM, respectively. Commonly used excipients did not interfere with sitagliptin phosphate measurement. The proposed method was used to measure the sitagliptin phosphate in its standard type, dosage form, and biological samples. The percent recovery ranged from 97.41–103.36%. The static quenching was shown to be responsible for quenching as indicated by the Stern–Volmer plot. The method was validated using ICH guidelines and profitably applied for the content uniformity test, resulting in a high percent recovery and small relative standard deviation. The proposed approach is effortless, susceptible, selective, economic, and provides a high precision and accuracy, and can be used to determine sitagliptin phosphate in the pharmaceutical industry. 相似文献
9.
Sevgi Tatar Ulu 《Luminescence》2012,27(5):426-430
A sensitive spectrofluorimetric method was developed for the determination of tizanidine in human plasma, urine and pharmaceutical preparations. The method is based on reaction of tizanidine with 1‐dimethylaminonaphthalene‐5‐sulphonyl chloride (dansyl chloride) in an alkaline medium to form a highly fluorescent derivative that was measured at 511 nm after excitation at 383 nm. The different experimental parameters affecting the fluorescence intensity of tizanidine was carefully studied and optimized. The fluorescence–concentration plots were rectilinear over the ranges 50–500 and 20–300 ng/mL for plasma and urine, respectively, detection limits of 1.81 and 0.54 ng/mL and quantification limits of 5.43 and 1.62 ng/mL for plasma and urine, respectively. The method presents good performance in terms of linearity, detection and quantification limits, precision, accuracy and specificity. The proposed method was successfully applied for the determination of tizanidine in pharmaceutical preparations. The results obtained were compared with a reference method, using t‐ and F‐tests. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
10.
A rapid, simple, accurate and highly sensitive spectrofluorimetric method was developed for the simultaneous analysis of nebivolol hydrochloride (NEB) and amlodipine besylate (AML). The method was based on measuring the synchronous fluorescence intensity of the drugs at Δλ = 40 nm in methanol. Various experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully studied and optimized. The calibration plots were rectilinear over concentration ranges of 0.05–1.5 µg/mL and 0.5–10 µg/mL for NEB and AML with limits of detection (LOD) of 0.010 and 0.051 µg/mL and limits of quantitation (LOQ) of 0.031 and 0.156, respectively. The peak amplitudes (2D) of the second derivative synchronous fluorimetry (SDSF) were estimated at 282 nm for NEB and at 393 nm for AML. Good linearity was obtained over the concentration ranges. The proposed method was successfully applied to the determination of the studied compounds in laboratory‐prepared mixtures, commercial single and laboratory‐prepared tablets. The results were in good agreement with those obtained using the comparison method. The mean percent recoveries were found to be 100.12 ± 0.77 and 99.91 ± 0.77 for NEB and AML, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
11.
Layth I. Abd Ali Aryan F. Qader Musher I. Salih Hassan Y. Aboul‐Enein 《Luminescence》2019,34(2):168-174
An easily performed, specific, sensitive, rapid, reliable and inexpensive procedure for the spectrofluorometric quantitation of ascorbic acid was proposed using acriflavine as a fluorescence quenching reagent. The procedure was based on the determined quenching effect of ascorbic acid on the natural fluorescence signal of acriflavine and the reaction between ascorbic acid and acriflavine in Britton–Robinson buffer solution (pH 6) to produce an ion‐associated complex. The reduction in acriflavine fluorescence intensity was detected at 505 nm, while excitation occurred at 265 nm. The relationship between quenching fluorescence intensity (?F) and concentration of ascorbic acid was linear (R2 = 0.9967) within the range 2–10 μg/ml and with a detection limit of 0.08 μg/ml. No significant interference was detected from other materials often found in pharmaceutical nutritional tablets. The obtained results were compared with those from high‐performance liquid chromatography and appeared in good agreement, with no important differences in precision or accuracy. The proposed spectrofluorimetric method was used to determine the amount of ascorbic acid in a number of commercial pharmaceutical nutritional supplement tablets with a 95% confidence performance. 相似文献
12.
Samadhan P. Pawar Laxman S. Walekar Dattatray B. Gunjal Dattatray K. Dalavi Anil H. Gore Prashant V. Anbhule Shivajirao R. Patil Govind B. Kolekar 《Luminescence》2017,32(6):918-923
We here for the first time demonstrate an analytical approach for the highly selective and sensitive detection of amoxicillin (Amox) in aqueous medium based on the fluorescence quenching of quantum dots (QDs). The change in fluorescence intensity of mercaptopropionic acid‐capped cadmium sulphide (MPA‐CdS) QDs is attributed to the increasing concentration of Amox. The results show that the fluorescence quenching of QDs by Amox takes place through both static and dynamic types of quenching mechanism. The fluorescence quenching of QDs with increase in concentration of Amox shows the linear range between 5 μg ml?1 and 30 μg ml?1 and the limit of detection (LOD) is 5.19 μg ml?1. There is no interference of excipients, which are commonly present in pharmaceutical formulation and urine samples. For the practical application approach, the developed method has been successfully applied for the determination of Amox in pharmaceutical formulations and urine samples with acceptable results. 相似文献
13.
Walid M. Ebeid Ehab F. Elkady Asmaa A. El‐Zaher Ramzia I. El‐Bagary Gabor Patonay 《Luminescence》2014,29(7):878-883
Aliskiren hemifumarate (ALS) and amlodipine besylate (AML) were simultaneously determined by two different spectrofluorimetric techniques. The first technique depends on direct measurement of the steady‐state fluorescence intensities of ALS and AML at 313 nm and 452 nm upon excitation at 290 and 375 nm, respectively, in a solvent composed of methanol and water (10: 90, v/v) . The second technique utilizes synchronous fluorimetric quantitative screening of the emission spectra of ALS and AML at 272 and 366 nm, respectively using Δλ of 97 nm. Effects of different solvents and surfactants on relative fluorescence intensity were studied. The method was validated according to ICH guidelines. Linearity, accuracy and precision were found to be satisfactory in both techniques over the concentration ranges of 1–15 and 0.4–4 µg/mL for ALS and AML, respectively. In the first technique, limit of detection and limit of quantification were estimated and found to be 0.256 and 0.776 µg/mL for ALS as well as 0.067 and 0.204 µg/mL for AML, respectively. Also, limit of detection and limit of quantification were calculated in the synchronous method and found to be 0.293 and 0.887 µg/mL for ALS as well as 0.034 and 0.103 µg/mL for AML, respectively. The methods were successfully applied for the determination of the two drugs in their co‐formulated tablets. The results were compared statistically with reference methods and no significant difference was found. The developed methods are rapid, sensitive, inexpensive and accurate for the quality control and routine analysis of the cited drugs in bulk and in pharmaceutical preparations without pre‐separation. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
14.
A simple and sensitive spectrofluorimetric method has been developed and validated for the determination of oseltamivir phosphate (OST) in pharmaceutical preparations. The method is based on the reaction between oseltamivir phosphate and o‐phthalaldehyde in presence of 2‐mercapto‐ethanol in borate buffer, pH 10.8, to give a highly fluorescent product measured at 450 nm after excitation at 336 nm. The different experimental parameters affecting the development and stability of the reaction product were studied and optimized. The fluorescence intensity–concentration plot is rectilinear over the range 0.05–1.0 µg/mL, with a lower detection limit of 5 ng/mL and limit of quantitation of 16 ng/mL. The developed method was successfully applied to the analysis of the drug in its commercial capsules and suspension, mean recoveries of OST were 99.97 ± 1.67% and 100.17 ± 1.18%, respectively (n = 3). Statistical comparison of the results obtained by the proposed and comparison method revealed no significant difference in the performance of the two methods regarding accuracy and precision. The proposed method was further extended to in vitro determination of the studied drug in spiked human plasma as a preliminary investigation; the mean recovery (n = 3) was 98.68 ± 5.8%. A reaction pathway was postulated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
A novel, quick, simple and highly sensitive spectrofluorimetric method was developed and validated for the determination of sitagliptin (SG) in its pharmaceutical formulations. The proposed method is based on investigation of the fluorescence spectral behavior of sitagliptin in an SDS micellar system. In an aqueous solution of phosphate buffer pH 4.0, the fluorescence intensity of SG in the presence of SDS was greatly enhanced, by 200%, i.e. twofold enhancement. The fluorescence intensity of SG was measured at 300 nm after excitation at 270 nm. The method showed good linearity in the range 0.03–10.0 µg/mL with a good correlation coefficient (r = 0.9998). The limits of detection and quantitation values were 5.31 and 16.1 ng/mL, respectively. The proposed method was successfully applied to the analysis of SG in its single and co‐formulated commercial tablets; the results were in good agreement with those obtained using a reference method. Application of the proposed method was extended to stability studies of SG after exposure to different forced degradation conditions according to the ICH guidelines, such as acidic, alkaline, thermal, photo‐ and oxidative stress. The chemical structure of certain potential degradation products (DPs) were investigated using LC‐MS. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
16.
A rapid, simple, and sensitive second‐derivative synchronous fluorimetric method has been developed and validated for the simultaneous analysis of a binary mixture of desloratadine (DSL) and montelukast sodium (MKT) in their co‐formulated tablets. The method is based on measurement of the synchronous fluorescence intensities of the two drugs in McIlvaine's buffer, pH 2.3, in the presence of carboxy methyl cellulose sodium (CMC) as a fluorescence enhancer at a constant wavelength difference (Δλ) of 160 nm. The presence of CMC enhanced the synchronous fluorescence intensity of DSL by 216% and that of MKT by 28%. A linear dependence of the concentration on the amplitude of the second derivative synchronous fluorescence spectra was achieved over the ranges of 0.10–2.00 and 0.20–2.00 µg/mL with limits of detection of 0.02 and 0.03, and limits of quantification of 0.05 and 0.10 µg/mL for DSL and MKT, respectively. The proposed method was successfully applied for the determination of the studied compounds in laboratory‐prepared mixtures and tablets. The results were in good agreement with those obtained with the comparison method. The high sensitivity attained by the proposed method allowed the determination of MKT in spiked human plasma with average % recovery of 100.11 ± 2.44 (n = 3). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
17.
18.
Orestis Ioannidis Basilios Papaziogas Panagiotis Tsiaousis George Paraskevas Evangelos J. Giamarellos‐Bourboulis Ioannis Koutelidakis 《Microbiology and immunology》2014,58(2):96/n-102
In order to investigate the effect of moxifloxacin on survival, lipid peroxidation and inflammation in immunosuppressed rats with soft tissue infection caused by Stenotrophomonas maltophilia, 144 white male Wistar rats were randomized into six groups: Groups A and B received saline or moxifloxacin once per day, respectively; Groups C and D received saline or moxifloxacin twice per day, respectively, and Groups E and F received saline or moxifloxacin three times per day, respectively. Blood samples were taken at 6 and 30 hr after administration of S. maltophilia. Malonodialdehyde (MDA), WBC counts, bacterial tissue overgrowth, serum concentrations of moxifloxacin and survival were assessed. Survival analysis proved that treatment with moxifloxacin every 8 hr was accompanied by longer survival than occurred in any other group. Tissue cultures 30 hr after bacterial challenge showed considerably less bacterial overgrowth in the spleens and lungs of moxifloxacin‐treated than in saline‐treated animals, but not in their livers. At 6 hr there were no statistically significant differences between groups. However, at 30 hr, MDA concentrations were significantly greater (P = 0.044) and WBC counts significantly lower (P = 0.026) in group D than in group C. No statistically significant variations were observed between the other groups. Moxifloxacin possibly stimulates lipid peroxidation and enhances phagocytosis, as indicated by MDA production and survival prolongation, without being toxic, as indicated by WBC count. Therefore, under the appropriate conditions, moxifloxacin has a place in treatment of infections in immunosuppressed patients and of infections caused by S. maltophilia. 相似文献
19.
Extended protein release from readily prepared, water-insoluble complexes with oppositely charged polyions is explored. Using hen egg-white lysozyme as a model, its sustained release from such complexes with a number of polyanions under physiological conditions has been demonstrated and rationalized. The rate of release varies orders of magnitude and is controlled by the nature of the polyanion (decreasing upon increase in its linear charge density, length, and hydrophobicity) and the complex particle size (the larger the particles, the slower the release). 相似文献
20.
生物传感器由生物识别元件和信号转换元件组成,能将目标化合物的浓度信号转化为易于检测的信号,现已被广泛应用于医药、环境、食品等各个领域。目前,可调节的色氨酸生物传感器在色氨酸及其衍生物的代谢工程和合成生物学研究中发挥着重要的作用,不同色氨酸生物传感器由于工作原理不同,在实际应用中具有各自的优势。本文综述了色氨酸生物传感器的研究进展,主要包括色氨酸生物传感器的类别、作用原理及优化策略,重点介绍了其在合成生物学中的典型应用实例。最后,针对色氨酸生物传感器设计与构建过程中面临的问题,提出了相应的解决方案,并对其发展趋势进行了展望。 相似文献