Determination of Oxybutynin in Pharmaceuticals <Emphasis Type="Italic">via</Emphasis> Reaction with Mixed Acids Anhydrides: Application to Content Uniformity Testing

Sensitive and simple spectrophotometric (Method I) and spectrofluorimetric (Method II) methods were developed and validated for the determination of oxybutynin HCl (OXB) in its dosage forms. The method was based on the reaction of OXB with malonic acid anhydride in acetic acid anhydride to form a highly yellow colored product that was measured at 375 nm spectrophotometrically. The same reaction product exihibits strong fluorescence that was measured at 440 nm after excitation at 390 nm. The factors affecting formation and stability of the reaction product were carefully studied and optimized, and the reaction mechanism was postulated. The absorbance-concentration plot is rectilinear over the range 4–40 μg/mL with LOD of 1.12 μg/mL and LOQ of 3.39 μg/mL. The fluorescence-concentration plot is rectilinear over the range 0.5–6 μg/mL with LOD of 0.11 μg/mL and LOQ of 0.33 μg/mL. The method was applied to the analysis of commercial tablets Detronin® and Uripan®. Statistical comparison of the results with those of the reference method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods respectively. The study was extended to content uniformity testing.     

Second-Derivative Synchronous Fluorescence Spectroscopy for the Simultaneous Determination of Fluphenazine Hydrochloride and Nortriptyline Hydrochloride in Pharmaceutical Preparations

A rapid, simple, and highly sensitive second-derivative synchronous fluorimetric (SDSF) method has been developed for the simultaneous analysis of binary mixtures of fluphenazine hydrochloride (FLZ) and nortriptyline hydrochloride (NTP) in their co-formulated tablets. The method is based upon measurement of the native fluorescence of these drugs at constant wavelength difference (Δλ)?=?120 nm in acetic acid. The different experimental parameters affecting the fluorescence intensity of the studied drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.25–3.0 and 1–10 μg/ml for FLZ and NTP respectively, with lower detection limits (LOD) of 0.05 and 0.18 μg/ml and quantitation limits of 0.15 and 0.53 μg/ml for FLZ and NTP respectively. The proposed method was successfully applied for the determination of the studied compounds in their synthetic mixtures and in commercial co-formulated tablets. The results obtained were in good agreement with those obtained by the reference methods.     

Determination of three analgesics in pharmaceutical and urine sample on nano poly (3, 4-ethylenedioxythiophene) modified electrode

Three analgesics, acetaminophen, acetylsalicylic acid, and dipyrone were determined by stripping voltammetry using nanosized poly(3,4-ethylenedioxythiophene)-modified glassy carbon electrode . The cyclic voltammetric behavior of the three analgesics was studied in aqueous acid, neutral, and alkaline conditions. One well-defined oxidation peak each for acetaminophen and acetylsalicylic acid and three oxidation peaks for dipyrone were observed in the cyclic voltammograms. The influence of pH, scan rate, and concentration revealed irreversible diffusion controlled reaction. A systematic study of the experimental parameters that affect the differential pulse stripping voltammetric response was carried out. Calibration was made under maximum peak current conditions. The scanning electron microscope analysis confirmed good accumulation of the drugs on the electrode surface. The range of study for both acetaminophen, acetylsalicylic acid were 0.015–0.4 and dipyrone was 0.025–0.4 μg/ml. The lower limit of determination for both acetaminophen, acetylsalicylic acid was 0.01 μg/mL and for dipyrone was 0.02 μg/mL. The suitability of the method for the determination of the three analgesics in pharmaceutical preparations and urine samples was also ascertained.     

Native Fluorescence Determination of Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceutical Preparations After Sorption on Sephadex SP C‐25

A simple, batch mode, solid phase spectrofluorimetric procedure has been developed for the determination of pyridoxine hydrochloride (PY) (vitamin B₆). The method is based on the measurement of the native fluorescence of the analyte at 395 nm (λ_exc = 295 nm) sorbed on Sephadex SP C‐25 beads. The cation‐exchange gel, previously equilibrated with the sample solution, is packed in a 1‐mm quartz cell in which the measurements are performed (diffuse transmitted fluorescence).

The method responds linearly in the measuring range of 50–500, 10–100 and 5–40 μg·l^? 1 with detection limits of 9.5, 2.3 and 0.60 μg·l^? 1 for 10, 25 and 50 ml of sample volume, respectively.

The relative standard deviation (n = 10) for the determination of 100 (10 ml), 60 (25 ml) and 30 μg·l^? 1 (25 ml) of PY is 1.3%, 2.2% and 3.7%, respectively. The method, which shows increasing sensitivity as the sample volume increases, was satisfactorily applied to the determination of vitamin B₆ in pharmaceutical preparations using the procedure for 10 ml of sample.     

In Situ Spectrodensitometric Determination of Methyl and Propyl Parabens,Benzoic and Sorbic Acids in Bulk Powder,Foods, and Pharmaceutical Formulations

ATLC spectrodensitometric procedure was developed for the determination of methyl paraben, propyl paraben, sorbic acid and benzoic acid as bulk powders or in pharmaceutical dosage forms and foods. The procedure was used for the determination of the two parabens singly or together and also was used for the determination of benzoic and sorbic acids singly because they were found singly in some commercial food and pharmaceutical products. The cited compounds were separated on silica gel with fluorescent indicator in systems, acetone-ethanol-aqueous ammonia 28%-ethyl acetate (84:3:9:9) for the determination of benzoic and sorbic acids and n-hexane-ethyl acetate-acetic acid (80:5:20) for the determination of the two parabens. Absorbance measurement (detection of reflectance) of separated compounds was carried out in situ, at 254 nm for the two parabens, sorbic acid, and at 228 nm for benzoic acid using multilevel calibration curves in the concentration ranges of 0.2—2.5 μg/spot, 0.5—3 μg/spot, and 2.5—12.5 μg/spot for sorbic acid, the two parabens, and benzoic acid, respectively. The results were evaluated by linear regression analysis. The mean % accuracies were found to be, mean ±C.V.(%), 99.65 ±0.963, 99.45±1.02, 99.60±0.825 and 99.34±0.969 for benzoic acid, sorbic acid, methyl paraben and propyl paraben in bulk powders, respectively. While in case of benzoic and sorbic acids in foods the mean % accuracies were found to be: 97.72±1.231 and 98.81±1.296, respectively. The mean % accuracies of methyl paraben, propyl paraben, sorbic acid in pharmaceutical dosage forms were found to be: 98.19±0.874, 97.830±0.799 and 98.36±0.572, respectively.     

化学发光分析法测定绿原酸

本文基于碱性介质中绿原酸对鲁米诺-铁氰化钾化学发光体系的抑制作用,首次建立了绿原酸的化学发光分析法,并探讨了其作用机理。方便简便、迅速、重复性好、灵敏度高。采用该法可测定1.0×10-8g/ml～1.0×10-5g/ml范围内的绿原酸,其检出限达到5.2×10-9g/ml,回收率为104%.     

Flow injection determination of metoclopramide based on KMnO4—HCHO chemiluminescence in a micellar medium

A novel flow injection chemiluminescence (CL) analysis method for the determination of metoclopramide in the presence of sodium dodecyl sulfonate (SDS) surfactant micelles is described. This method is based on the luminescent properties of the KMnO₄-HCHO-metoclopramide in acid medium sensitized by SDS. The optimized experimental conditions were evaluated and the possible mechanism was discussed. The CL increase is linearly related to the concentration of metoclopramide in the range 0-80.0 μg/ml with a detection limit of 31.3 ng/mL (S/N=3).The relative standard deviation for 20.0 μg/ml samples was 2.6% (n=11). The proposed method has been successfully applied to the determination of metoclopramide in tablets.     

Fluorimetric Determination of Cerium(IV) with Ascorbic Acid

A simple, sensitive, and selective method for the determination of cerium(IV), based on the oxidative reaction between cerium(IV) and ascorbic acid, has been described. The fluorescence comes from Ce(III) at λ_excitation 298 nm and λ_emission 358 nm, which, in turn, is obtained from the oxidation of ascorbic acid by Ce(IV) in the presence of sulfuric acid. The optimum conditions such as concentrations of ascorbic acid, sulfuric acid media and pH of the buffer solution were investigated. The fluorescent intensity of the system is linear over the range 0.0531 μg/ml to 0.3322 mg/ml Ce(IV) and detection limit and correlation coefficient are 0.0145 μg/ml and R=0.99987,respectively.     

催化动力学光度法测定抗癌中草药中痕量硒Ⅰ.溴酸钾—罗丹明B体系

研究了硝酸介质中痕量硒(Ⅳ)催化溴酸钾氧化罗丹明B的褪色反应及动力学条件, 建立了动力学光度法测定痕量硒(Ⅳ)的新方法, 其灵敏度为0.905 μg·L-1, 测定范围0～9.6 μg·L-1。用于测定抗癌中草药中的硒(Ⅳ), 获得了满意的结果。     

Rapid, Sensitive and Highly Selective (15)N Analysis of (15)N Enriched Nitrite in Water Samples and Soil Extracts by Nitric Oxide Production and CF-QMS Measurement

Abstract Nitrite is a very important intermediate in many microbiological N transformations in soils and water. The stable isotope (15)N is often used to investigate these processes. The determination of (15)N in low concentrations of nitrite in the presence of large concentrations of nitrate is very difficult. Methods used so far for the isotope analysis of nitrite are unsatisfactory, because the nitrite must be calculated as the difference between nitrate plus nitrite and nitrate alone. More useful are mehods by which the nitrite is selectively converted into a chemical form that is suitable for (15)N analysis and that is free from interference from other N species, particularly nitrate. Using this principle in the present study we developed a method where the nitrite is reduced to nitric oxide by iodide in acid medium. This reaction is fast and quantitative, and the (15)N abundance of NO can be precisely measured by continuous flow mass spectrometry. This method is used for samples from tracer experiments with artificially enriched nitrogen 15. Therefore, the use of simple quadrupole mass spectrometers directly linked to the reaction unit is possible with sufficient precision (Reaction-Continuous Flow Quadrupole Mass Spektrometry-RCFQMS). Using the technique developed sample volumes up to 10ml containing at least 1.0 μg nitrite-N (0, 1 μg/ml) with a (15)N abundance of ? 0.42 at.% gave a precision of RSD ? ± 3%.     

Comparative Study of the Ratio Spectra Derivative Spectrophotometry,Derivative Spectrophotometry and Vierordt's Method Appued to the Analysis of Lisinopril and Hydrochlorothiazide in Tablets

Abstract

Three new spectrophotometric methods are described for the determination of lisinopril and hydrochlorothiazide in their binary mixturer: First derivative spectrophotometry ratio spectra derivative and Vierordt's method. The procedures do not require any prior separation. In the derivative spectrophotometry, the dA/dλ values in the first derivative spectra of the mixture were measured at 269.6 nm for lisinopril and at 279.8 nm for hydrochlorothiazide. The calibration graphs were linear in the range 25.56–129.50 μg.ml^?1 for lisinopril and 10.60–139.80 μg.ml^?1 for hydrochlorothiazide. In ratio spectra derivative spectrophotometry, the calibration graphs for 15.68–129.50 μg.ml^?1 lisinopril and for 5.98–139.80 μg.ml^?1 hydrochlorothiazide were obtained by measuring the signals at 253.7 nm and 243.6 nm for lisinopril and at 280.1 nm and 270.8 nm for hydrochlorothiazide. In Vierordt's method, A¹ ₁ (1 %, 1 cm) values of lisinopril and hydrochlorothiazide were determined at 259.8 nm and 272.7 nm in the zero-order spectra. The quantity of both compounds were calculated by using the A¹ ₁ (1 %, 1cm) values. The methods were successfully applied to a pharmaceutical formulation for determination of both active compounds.     

Determination of free iodine concentration in an X-ray contrast agent

Based on the analysis of the absorption spectra of solutions of iodine in ethanol, we propose a simple and sensitive (at a level of 1 μg/g) method for determination of the concentration of free (not bound to polymer) iodine in substances synthesized from ether oils and iodine. The method uses absorption of molecular iodine in the UV region. Iodine dissolved in alcohols has a rather large absorption cross section in the UV region. These absorption bands can be used to detect very small quantities of iodine. It is shown that, for iodine concentrations in the 1–50 μg/g range, the intensity of absorption band at a wavelength of 359 nm depends linearly on the iodine concentration, which allows one to use this band to determine the concentration of iodine not bound with the polymer in the X-ray contrast material.     

The role of sensitivity of ALA (PpIX)-based PDT on Human embryonic kidney cell line (HEK293T)

Present study evaluates the effects of photodynamic therapy (PDT) with aminolevulinic acid (5-ALA) as photo sensitizer using Human embryonic kidney (HEK293T) cell line as an experimental model. Porphyrins derivatives are used as active cytotoxic antitumor agents in PDT. Above mentioned cell line were irradiated with red light (a diode laser, λ = 635 nm) at different doses (0–160 J/cm²) of light. The influence/effectiveness of incubation time, various concentrations of aminolevulinic acid (5-ALA) and light doses on the cellular viability was studied. HEK293T cells were deliberated by exposing the ALA-PpIX (0–1000 μg/ml) of concentrations. The optimal uptakes of photosensitizer (PS) in cell lines were investigated by means of spectro photo metric measurements. Cells viability was determined by means of neutral red assay (NRA). It was observed that alone, neither photosensitizer nor light dose have significant effect on cells viability, but optimal concentration of PS along with suitable dose of light exhibit effective impact on the viability of cell. Our results showed that light doses of 40 J/cm² demonstrates effective PDT outcome for HEK293T cell line when incubated with 400 μg/ml, with wrapping up view that HEK293T cell line is very sensitive to ALA-mediated PDT as compared to cell line published in our data. At the end results has been verified by using reactive oxygen species (ROS) measure test.     

Spectrophotometric Determination of Trace Amounts of Mercury with 3-(2-Thiazolylazo)-2, 6-Diaminopyridine and Gelatine

Abstract

A sensitive method for the determination of trace amounts of mercury by complexation with 3-(2-Thiazolylazo)-2, 6-diaminopyridine (2, 6-TADAP) is described. Hg(II) forms a 1:2 complex with the reagent. Beer's law is obeyed over the range 5–40 μg in the total volume of 10 ml. The molar absorptivity was found to be 1.4 × 10⁴ L mol^?1 cm^?1. This method is simple, rapid and involves no extraction steps whereby the use of gelatine as a solubilizing agent is described.     

Monitoring dissolved active trace elements in biogas plants using total reflection X-ray fluorescence spectrometry

Generally, full-scale biogas plants require trace elements supplementation to sustain a stable process. The aim was to apply total reflection X-ray fluorescence (TXRF) to monitor the dissolved, active elements, for the first time, at μg/L levels in biogas plants. The digester liquid is comparable to sludge with high solids content and high salt concentrations. The ions are usually measured in the dried fermenter slurry after acid digestion in its inactive bound form, although microorganisms can take up only dissolved ions as active agent. In this study, a procedure was developed to monitor dissolved ions in such environmental processes to prevent an overdose or underdose. The analytical figures of merit considered were the lowest possible limit of detection, the recovery of spiked ions and linearity. Samples were spiked with nickel, selenium and tungsten in the range of 10–200 μg/L. Highest recovery rates of >93% for concentrations of 10 to <100 μg/L were obtained after the samples were centrifugated twice, followed by application of microwave-assisted acid digestion. The calculated lowest limit of detection was 2–4 μg/L. The developed method was first tested in laboratory-scale biogas digesters with wheat straw as substrate. Successful application of TXRF was also achieved in a full-scale biogas plant to estimate the dynamics of “active” trace element ions in the range of 2–1,000 μg/L for several months. Therefore, cost-effective biogas plant management is possible through the application of TXRF spectrometry to monitor trace elements.     

快速分光光度法同步测定地下水中赤霉素和草甘膦的相互影响

随着设施化农业的迅速发展,大量农药的不规范使用使高浓度赤霉素和草甘膦集中进入环境的风险增大(特别是地下水环境),因而关于二者在地下水中残留量测定方法的研究尤为重要。分光光度法、气相色谱-质谱法、液相色谱法和液相色谱-质谱法是普遍使用的赤霉素和草甘膦测试方法,分光光度法由于操作简便而在快速检测中被广泛应用。然而,关于分光光度计快速同时测定地下水中赤霉素和草甘膦的方法,尚未有研究关注其相互影响。故建立和优化了快速分光光度法同步测定地下水中赤霉素和草甘膦的分析方法,并研究二者同步测定时的相互影响。结果表明,赤霉素校准曲线在0～20和0～100 μg范围内,具有良好线性相关关系(R2>0.99),方法检出限为0.48 μg。水样测定时,含15～150 μg赤霉素的平均回收率为71.3%±1.9%,方法精密度的RSD<10%;草甘膦校准曲线在0～8和5～15 μg范围内,具有良好线性相关关系(R2>0.99),方法检出限为0.82 μg。水样测定时,含3～10 μg草甘膦的平均回收率为98.4%±8.1%,方法精密度的平均RSD<10%。同时,根据浓度效应研究赤霉素和草甘膦快速分光光度法测定的相互影响表明,草甘膦0～100 mg·L-1对赤霉素的回收率没有显著影响,但是会降低其测试精密度;赤霉素2 mg·L-1会导致草甘膦测试中回收率由108.72%±4.33%增加到117.06%±3.2%。     

超声辅助固相萃取分离/ICP-AES测定食品包装铝材中砷的研究

原子光谱法直接测定纯铝材中的砷,受到铝基体的干扰。实验表明,当被测试液中Al的质量浓度大于等于As的5 000倍时,测量误差大于5%。为了降低被测试液中铝的浓度以消除干扰,利用对Al3+吸附作用强的强酸型阳离子交换纤维作为固相萃取剂,通过对萃取剂用量、萃取温度、pH值等条件的研究,得到以下方法：0.900 0 g强酸型阳离子交换纤维在55 ℃,pH 2.0的试液中,对Al3+进行超声辅助萃取5 min,此时以砷酸形式存在的砷不被萃取而留在试液中供测定。结果表明,10.00 mL含砷1.00 μg,铝20.0 mg的试液经过分离后,其中砷未见损失,而残留铝质量浓度约为砷的2 000倍,已不干扰ICP-AES测定As。方法检出限(3 s)为0.027 μg·mL-1,方法定量下限(10 s)为0.091 μg·mL-1。本方法已用于合成样、铝制饮料易拉罐和烘烤食品用铝箔等样品中As的测定,标准加入的回收率98.3%~105%;RSD(n=3) 0.1％~4.3％;结果显示,在本实验所测的铝易拉罐和烘烤用铝箔样品中,砷的含量均低于国家标准(GB/T 3190—2008)的限定值。     

固载化离子液体富集-流动注射分光光度法测定废水中痕量汞

以表面浸渍固载有疏水性室温离子液体—1-己基-3-甲基咪唑六氟磷酸盐(1-hexyl-3-methylimidazolium hexafluorophosphate,[C₆mim]PF₆)的Amberlite XAD-7大孔树脂为固相萃取微柱的吸附剂,建立了微柱在线富集和流动注射-分光光度法测定废水中痕量游离态汞的新方法。在酸性介质中和十六烷基三甲基溴化铵(CTMAB)存在下,Hg2+与双硫腙反应生成红色的中性配合物可被微柱有效地定量富集。在优化的实验条件下,方法的线性范围为0.35～50 μg·L-1 Hg2+,检出限为0.067 μg·L-1 Hg2+。进样体积为50 mL时,Hg2+的富集因数为25倍。对环境水质汞标准样品(GSBZ50016-90)和加标废水样品的测定,回收率在99%～103%。     

萃取荧光法测定药物及体液中硫酸氢氯吡格雷含量

提出了简单、灵敏的测定药物及体液中硫酸氢氯吡格雷含量的荧光新方法。利用荧光法研究了硫酸氢氯吡格雷与茜素红的作用,基于在盐酸介质中硫酸氢氯吡格雷能与茜素红形成离子对化合物,该化合物能被二氯甲烷萃取,当用428 nm波长激发时在550 nm左右能发射较强的荧光。因荧光强度与硫酸氢氯吡格雷浓度在一定范围内存在定量关系,从而建立了测定硫酸氢氯吡格雷含量的新方法。当盐酸溶液的浓度为0.3 mol·L-1时,形成的离子对比较稳定,硫酸氢氯吡格雷浓度在1.0～11.0 μg·mL-1 范围内时离子对荧光强度与硫酸氢氯吡格雷浓度呈良好的线性关系,线性方程为F=53.32+35.01c(μg·mL-1),r=0.994,检出限为0.11 μg·mL-1。硫酸氢氯吡格雷在药物和人血清、尿液中的回收率分别为90.6%～99.3%,104.6%～109.3%,96.3%～105.0%,干扰实验表明常用药物辅料对它的测定没有干扰。用本法测定了硫酸氢氯吡格雷片、人血清及尿样中硫酸氢氯吡格雷含量,结果令人满意。实验结果表明本法快速,灵敏度高,准确度好,可用于实际样品中硫酸氢氯吡格雷含量的测定。     

Simultaneous determination of aluminum (III) and iron (III) by first-derivative spectrophotometry in alloys

A highly sensitive and selective first-derivative spectrophotometric method has been developed for the determination of aluminum and iron in mixtures. The method is based on the formation of the binary complexes of aluminum and iron with Alizarin yellow R (AYR) 5-[4-nitrophenylazo]salicylic acid at pH 2.0 with molar absorptivity of 1.1∙10⁴ l⋅mol^–1⋅cm^–1. A zero-crossing technique is found suitable for the direct measurement of the first derivative value at the specified wavelength, so aluminum and iron were thus determined in the ranges 1.3–5.4 μg/ml and 1.1–8.3 μg/ml, respectively, in the presence of both components. The detection limits were found to be 1.4 ng/ml for aluminum and 2.8 ng/ml for iron. The relative standard deviations were in all cases less than 1.5%. The proposed method was successfully applied for the simultaneous determination of aluminum and iron in certified reference aluminum samples.