Preparation of Inclusion Complex of Camptothecin with Cucurbit7uril and Exploration of the Properties of Inclusion Complex System / 中国药学杂志

OBJECTIVE: To prepare and verify the anticancer drug camptothecin(CPT) and its inclusion complex with cucurbit[7]uril(CB[7]). METHODS: Camptothecin-cucurbit[7]uril inclusion complex was prepared by the lyophilization. The complex was characterized by fluorescence spectroscopy, Fourier transformation-infrared spectroscopy(FI-IR), differential scanning calorimetry(DSC), X-ray diffraction(XRD) and 1H-NMR. The dissolution properties of the inclusion complex was analyzed by ultraviolet spectrum. RESULTS: The formation of 1:2 complex with CB[7] in aqueous solution was confirmed by fluorescence spectroscopy and the apparent stability constant was 3.95×1012 L2•mol-2.The stability and solubility of camptothecin was significantly improved after it was included with cucurbit[7]uril. CONCLUSION: Stable complex can be formed between camptothecin and cucurbit[7]uril,and the solubility of camptothecin is increased by CB[7] significantly.

Interaction of oleanolic acid and its derivatives with bovine serum albumin by spectrofluorimetry / 中国药科大学学报

Oleanolic acid was chemically modified to improve its interaction with bovine serum albumin,thus to increase the mutual binding ability.As a lead compound,oleanolic acid reacted with Jones-reagent,then methyl iodide and finally hydroxylamine to obtain four different derivatives.Their structures were confirmed by IR and 1H NMR analysis.The interaction between these derivatives and bovine serum albumin and the effect of temperature and trace metal ions as Cu2+ and Co2+ on the interaction were investigated by fluorescence spectroscopy.All these derivatives exhibited improvement of the interaction compared with oleanolic acid with 16 times stronger for OA2.The interaction also increased with the presence of trace metal ions as Cu2+ and Co2+.These results indicate that chemical modification can improve the interaction of oleanolic acid with bovine serum albumin.

Antioxidant activity and protective role on protein glycation of synthetic aminocoumarins

Background: Synthesized aminocoumarins are heterocyclic compounds possessing potential for the treatment of insulin-dependent diabetes mellitus with unexplored anti-glycative action. Results: In this study 4-aminocoumarin derivatives (4-ACDs) were evaluated in vitro for antiglycation (AG) activities by using the human serum albumin (HSA)/glucose system, for 8 weeks of incubation. The glycation and conformational alteration of HSA in the presence of the tested compounds were evaluated by Congo red assay, fluorescence and circular dichroism spectroscopy. The antioxidant (AO) capacity were also tested by four different assays including: DPPH (2,2'-diphenyl-1-picrylhydrazyl radical), ABTS (2,2-azinobis (3-ethylbenzothiazoline-6-sulphonate) diammonium salt), FRAP (ferric reducing antioxidant power) and β-carotene-linoleic acid assay. The tested compounds showed AG and AO effects. The intensity of the accomplished AO potential is related to the type of the used assay. Significant alterations in the secondary (monitored by CD spectropolarimetry) and tertiary structure (assessed by spectrofluorimetry) of HSA upon glycation were mitigated by the 4-ACDs, suggesting their suppressive role in the late stage (post-Amadori) of the HSA glycation. Conclusions: By the analogues, in vitro ascertained AO and AG properties of 4-ACD may be recognized as rationale for their protective role against oxidative changes of proteins, thereby precluding diabetic complications in humans.

Development and Validation of a Stability Indicating Spectrofluorimetric Method for the Determination of Lanzoprazole via its Degradation Product.

A simple and a stability indicating spectrofluorometric method was developed and validated for the analysis of lanzoprazole via its degradation product in formulation. The proposed method was based on measuring the fluorescence intensity of the degradation products at 410 nm for the emission wavelength and at 322 nm for the excitation wavelength. The method was validated in accordance with the ICH requirements, which involved accuracy, precision, linearity, selectivity and both limit of detection and limit of quantification. Linearity was obtained in concentration range 1– 10 μg/ml. The mean percentage recoveries were 99.39 ± 0.11%. The degradation product was obtained in acidic stress condition. The proposed procedure was successfully applied for the determination of lanzoprazole in pure form, laboratory-prepared mixtures, tablet and expired batch. Statistical comparison between the results obtained by the suggested method and that obtained by the official method for the determination of the drug was done and it was found that there were no significant differences between them. For ease and convince of such method, where analysis can be done within a short period of time in comparison with the chromatographic methods. The method was validated according to United States Pharmacopeia Guidelines.

Development of dissolution test method for a telmisartan/amlodipine besylate combination using synchronous derivative spectrofluorimetry

The dissolution process is considered an important in vitro tool to evaluate product quality and drug release behavior. Single dissolution methods for the analysis of combined dosage forms are preferred to simplify quality control testing. The objective of the present work was to develop and validate a single dissolution test for a telmisartan (TEL) and amlodipine besylate (AML) combined tablet dosage form. The sink conditions, stability and specificity of both drugs in different dissolution media were tested to choose a discriminatory dissolution method, which uses an USP type-II apparatus with a paddle rotating at 75 rpm, with 900 mL of simulated gastric fluid (SGF without enzymes) as the dissolution medium. This dissolution methodology provided good dissolution profiles for both TEL and AML and was able to discriminate changes in the composition and manufacturing process. To quantify both drugs simultaneously, a synchronous first derivative spectrofluorimetric method was developed and validated. Drug release was analyzed by a fluorimetric method at 458 nm and 675 nm for AML and TEL, respectively. The dissolution method was validated as per ICH guidance.

O processo de dissolução é considerado como uma importante ferramenta in vitro para avaliar a qualidade do produto e o comportamento de liberação do fármaco. Prefere-se um ensaio único de dissolução para formas farmacêuticas contendo associação de fármacos pela simplificação dos testes de controle de qualidade. O objetivo do presente trabalho foi desenvolver e validar um teste de dissolução único para forma farmacêutica comprimidos contendo telmisartana (TEL) e besilato de anlodipino (AML) associados. Condições "sink", estabilidade e especificidade de ambos os fármacos nos diferentes meios de dissolução foram avaliadas para selecionar um método de dissolução discriminatório, que utiliza um aparato do tipo II da USP, com pás girando a 75 rpm e 900 mL de fluido gástrico simulado (SGF sem enzima) como o meio de dissolução. Estas condições proporcionaram bons perfis de dissolução para ambos, TEL e AML, sendo capaz de discriminar as mudanças na composição e processo de fabricação. Para quantificar os dois fármacos simultaneamente, um método de fluorescência derivada sincronizado foi desenvolvido e validado. A quantidade de fármaco liberado foi analisada pelo método fluorimétrico em 458 e 675 nm para a AML e TEL, respectivamente. O método de dissolução foi validado de acordo com a orientação da ICH.

Optimization of a spectrofluorimetric method based on a central composite design for the determination of potassium losartan in pharmaceutical products

Here, a spectrofluorimetric method for the determination of potassium losartan (PL) in pharmaceutical products is described. The effects of critical parameters, pH, acid molarity, and temperature, on the fluorescence intensity of PL were analyzed, and these parameters were optimized using a central composite design (CCD). The highest fluorescent intensity at excitation (λex) and emission (λem) wavelengths of 248 nm and 410 nm, respectively, was achieved using 0.01 M sulfurous acid (pH 2) at 21.6 °C. Under optimum conditions, the method was linear from 0.025-0.5 µg/mL, with a reasonably high correlation coefficient (0.9993). Furthermore, the method was very sensitive (LOQ, 0.006), accurate (RE, ≤7.06), and precise (%RSD, ≤6.51). After development and validation of the method, samples containing PL were analyzed with this method, and the obtained data were statistically compared with those obtained with a previously published reference method using a two one-sided equivalence test (TOST). According to the data, the results from the proposed and reference assays were equivalent.

Descreve-se método espectrofluorométrico para a determinação de losartana potássica (PL) em produtos farmacêuticos. Os efeitos de parâmetros críticos (pH, molaridade ácida e temperatura) na intensidade da fluorecência foram otimizados usando o planejamento de componente central (DCC). A mais alta intensidade fluorescente com λex=248 nm e λem= 410 nm foi obtida usando ácido sulfúrico 0.01 M (pH 2) e 21.6 ºC. Nas condições ideais, a linearidade do método foi estabelecida na faixa de concentração de 0.025-0.5 µg/mL com coeficiente de correlação bastante elevado (0.9993). Além disso, o método foi muito sensível com valor de LOQ 0.006, exato (RE≤7.06) e preciso (RSD%≤6.51). Depois do desenvolvimento e validação do método, amostras de medicamentos contendo PL foram analisadas com este método e os resultados obtidos foram comparados estatisticamente com método de referência, publicado anteriormente, usando o Teste de equivalência TOST (Teste de Equivalência Unilateral). De acordo com os dados estatísticos, os resultados do ensaio de referência e do método proposto foram equivalentes.

Development of a spectrofluorimetric method for determination of thiabendazole in tablets.

In this study a spectrofluorimetric method has been developed for determination of thiabendazole drug active compound in tablets. For this purpose; thiabendazole drug active compound was measured fluorescence intensities at excitation (ex) and emission (em) wavelength in various solvents. Suitable solvent was determined for each compound from calibration graphs and tablets' excipients. Spectrofluorimetric method for the determination of thiabendazole in tablet was described under the optimum conditions. The wavelengths of excitation and emission were 370,0 nm and 428.8 nm respectively. The fluorescence intensity was linearly related to the drug concentration and the method was found to be highly accurate and precise, having a relative standard deviation of less than 0.8 %. This proposed method was applied to the determination of thiabendazole in tablet. The validity of the method was tested by the recovery studies of standard addition to pharmaceuticals and the result was found to be satisfactory. The results compared with official USP 24 HPLC method were in good agreement and statistical comparison by means of Student’s t-test and the variance ratio F-test showed no significant difference between the two methods. The proposed method is simple and sufficiently precise for quality control purposes in routine analysis.

Development and validation of spectrophotometric and spectrofluorimetric methods for simultaneous determination of Tofisopam.

Two simple, rapid and accurate spectrophotometric and spectrofluorimetric methods developed for the determination of Tofisopam (TF) in pure form and in pharmaceutical formulation. The spectrophotometric method (A) is based on the reduction of ferric into ferrous in presence of 1, 10-phenanthroline to give an orange –red colored ferroin complex measured at 510 nm. Method (B) spectrofluorimetric method is based on the oxidative coupling reaction of TF with 3-methylbenzothiazolin-2-one hydrazone (MBTH) hydrochloride in presence of cerium (IV) ammonium sulfate in an acidic medium. The quenching effect of TF on the fluorescence of excess cerous ions is measured at the emission λem 345 nm with excitation λex at 296 nm. The factors affecting the reactions were carefully studied and optimized. Beer,s law is obeyed in the range of 2-12 μg ml-1 for both methods with the mean percentages recovery of 100.04 ± 0.445 and 99.29 ± 0.563 for method (A) and (B), respectively. The two proposed methods were successfully applied for the determination of TF in Nodeprine tablets. Statistical comparison between the results obtained by these methods and that obtained by the official method for the determination of the drug was done, and it was found that there was no significant differences between them.

Spectrofluorimetric method for determination of some angiotensin Ⅱ receptor antagonists / 药物分析学报

A simple,rapid,accurate and highly sensitive spectrofluorimetric method has been developed for determination of some angiotensin Ⅱ receptor antagonists (AIIRA's),namely Losartan potassium (Los-K),Irbesartan (Irb),Valsartan (Val) and Candesartan cilexetil (Cand) in pure forms as well as in their pharmaceutical dosage forms.All the variables affecting the relative fluorescence intensity (RFI) were studied and optimized.Under the optimum conditions,linear relationships with good correlation coefficients (0.9982-0.9991) were obtained over the concentra tion range from 0.006μg/mL to 1.7μg/mL.Good accuracy and precision were successfully obtained for the analysis of tablets containing each drug alone or combined with hydrochlor othiazide (HCTZ) without interferences from the co-formulated HCTZ or the additives commonly present in tablets.

Comparison of thin-layer chromatography, spectrofluorimetry and bright greenish-yellow fluorescence test for aflatoxin detection in corn

In this study the bright greenish-yellow fluorescence test, widely used by the corn milling industry, was compared to the thin-layer chromatography (TLC) and spectrofluorimetry methods for aflatoxin detection in 40 corn samples naturally contaminated by the Aspergillus section Flavi. According to the corn processing industry criteria, all the samples were adequate for human and animal consumption by the bright greenish-yellow fluorescence test, but TLC and spectrofluorimetry analysis detected aflatoxins above the maximum tolerated limit (20 µg/kg) in 7 and 8 samples, respectively. Aflatoxins were detected in 16 (40 percent) corn samples by TLC, with levels ranging from 4.0 to 54.0 µg/kg (mean 19.97 ± 15.97 µg/kg), and in 25 (62.5 percent) samples by spectrofluorimetry, with levels ranging from 1.0 to 58.66 µg/kg (mean 17.14 ± 17.81 µg/kg). The results indicated a good correlation (ρ = 0.97) between TLC and spectrofluorimetry for aflatoxin determination in naturally contaminated corn. The bright greenish-yellow fluorescence test was simple and quick, but it showed 20 percent false-negative results, suggesting its use only as screening method for detecting the suspected lots of grains that should be tested further for aflatoxin by more sensitive methods.

Neste trabalho a contagem de fluorescência luminosa amarelo-esverdeada, amplamente utilizada pela indústria de processamento de milho, foi comparada à cromatografia em camada delgada (CCD) e espectrofluorimetria para detecção de aflatoxinas em 40 amostras de milho naturalmente contaminadas por Aspergillus section Flavi. De acordo com os critérios da indústria processadora de milho, todas as amostras estavam adequadas para o consumo humano e animal pela contagem de fluorescência luminosa amarelo-esverdeada (CFLAE), porém as análises por CCD e espectrofluorimetria detectaram aflatoxinas acima do limite máximo tolerado (20 µg/kg) em 7 e 8 amostras, respectivamente. As aflatoxinas foram detectadas em 16 (40 por cento) amostras por CCD, com níveis variando de 4,0 a 54,0 µg/kg (média 19,97 ± 15,97 µg/kg) e, em 25 (62,5 por cento) amostras por espectrofluorimetria, com níveis variando de 1,0 a 58,66 mg/kg (média 17,14 ± 17,81 µg/kg). Os resultados indicaram uma boa correlação (ρ=0,97) entre CCD e espectrofluorimetria para detecção de aflatoxinas em amostras de milho naturalmente contaminadas. A CFLAE, apesar da simplicidade e rapidez, apresentou 20 por cento de resultados falso-negativos, sugerindo seu uso apenas como método de triagem para detecção de lotes de grão suspeitos de contaminação que devem ser avaliados posteriormente por métodos mais sensíveis.

Emission fi lter design to detect poultry skin tumorsusing fl uorescence hyperspectral imaging / Diseño del filtro de emisión para detectar tumores cutáneos en canales de aves usandoimagenes de fluorescencia hiperespectral / Desenho de um filtro de emissão para detectar tumores cutâneos em carcaças de avesusando imagens de fluorescência hiperespectral

This paper presents an optimal emission filter of the fluorescence imaging system to detect skintumors on poultry carcasses. The secure production of disease-free meat is crucial in the mass productionenvironment. The fluorescence spectra have been gaining the practical use in many areas because thefluorescence response is very sensitive in detecting trace elements. The spectral features of the specimenare embedded across broad spectral bands and have been analyzed in various methods. We apply thelinear discriminant analysis to determine the emission filter of fluorescence imaging system. It providesthe optimal attenuation of emission wavelengths in terms of discriminant power. The attenuation valuesprioritize wavelengths to select significant spectral bands. With the optimal filter, skin tumor parts ofchicken carcasses are enhanced saliently in resultant fluorescence images.

La producción de carne libre de enfermedades es crucial en producción pecuaria intensiva. Losespectros de fluorescencia se han estado usando en forma práctica en muchas áreas, ya que la respuestade fluorescencia es muy sensible para detectar elementos traza. Este artículo presenta un óptimo filtrode emisión para el sistema de imágenes de fluorescencia utilizado para detectar tumores cutáneos encanales de pollo. Las características espectrales de la muestra --insertas en bandas espectrales amplias- sehan analizado por varias metodologías. En este artículo aplicamos el análisis lineal discriminante paradeterminar el filtro de emisión del sistema de imágenes por fluorescencia, mediante el cual se obtiene laatenuación optima de las ondas de emisión en términos de poder discriminante. Los valores de atenuaciónpriorizan las longitudes de onda para seleccionar las bandas espectrales más significativas. Gracias a lautilización de este filtro optimizado, los tumores cutáneos existentes en la canal de pollo son magnificados,de modo que se alcanzan a diferenciar perfectamente en las imágenes de fluorescencia resultantes.

A produção de carne livre de doenças é crucial em produção pecuária intensiva. Os espectros defluorescência temse estado utilizando em forma prática em muitas áreas, já que a resposta da fluorescênciaé muito sensível para detectar elementos traça. Este artículo apresenta um óptimo filtro de emissão parao sistema de imagens de fluorescência utilizado para detectar tumores cutâneos em carcaças de frangos.As características espectrais da amostra, insertas em bandas espectrais amplas são utilizadas por variasmetodologias. Neste artículo aplicamos a análises linear discriminante para determinar o filtro de emissãodo sistema de imagens por fluorescência, mediante o qual obtém-se a atenuação óptima das ondas deemissão em termos de poder discriminante. Os valores de atenuação dão prioridade às longitudes deonda para seleccionar as bandas espectrais mais significativas. Graças à utilização do filtro optimizado,os tumores cutâneos existentes na carcaça de frango são magnificados, de fato que são diferenciadosperfeitamente nas imagens de fluorescência resultantes.

Study of the Interactions between Tetracyclines and Human Serum Albumin / 中国药房

OBJECTIVE:To discuss the interactions between tetracyclines(oxytetracycline,methacycline,tetracydine,and doxycycline)and human serum albumin(HSA).METHODS:The binding constants and the number of biding sites of tetracyclines with human serum albumin(HSA)at various temperatures were studied by using UV-visible absorption spectrum and spectrofluorimetry,and the enthalpy change(?H)entropy change(?S)were computed.According to the Frster nonradiative energy transfer theory,the critical distances R0 between donators and acceptors were derived.RESULTS:The thermodynamic parameters were as follows:?H0;R0:oxytetracycline:(1.82 nm),and methacycline(2.31 nm),tetracydine(2.98 nm),doxycycline(2.26 nm).CONCLUSION:Tetracyclines can all cause HSA's fluorescence quenching.The quenching mechanism is static quenching.The main acting force between them is electrostatic attraction.

Pesquisa de toxina paralisante dos moluscos em pescado / Investigation of paralyzing toxin from molluscs in fish

A toxina paralisante dos moluscos foi pesquisada em amostras de ostras, mariscos e peixes, colhidas em diferentes praias do litoral paulista. Foram empregados dois procedimentos analíticos: o químico e o bioensaio. Em decorrência do aparecimento de manchas avermelhadas nas águas e mortalidade de peixes na região, no período de agosto a setembro de 1983, suspeitou-se do fenômeno de "maré vermelhra". A toxina não foi detectada em nenhuma das amostras, pelos dois métodos empregados, que permitem segurança dos resultados, considerando que os testes foram realizados com o padrão de saxi toxina (AU).