A Simple,Rapid, and Validated LC Method for the Estimation of Nimesulide in Human Serum and Its Application in Bioavailability Studies

Abstract

A new, simple, and rapid, sensitive reversed phase liquid chromatographic method was developed for the estimation of nimesulide in blood serum using a 60:40 mixture of acetonitrile and orthophosphoric acid (pH 3.0) as the mobile phase at 230 nm. The mobile phase and other chromatographic conditions were optimized to minimize interference from the serum matrix and at the same time provide sufficient sensitivity for the method to be adopted for in vivo studies of oral formulations of nimesulide. Acetonitrile was used to precipitate proteins from serum during sample preparation. Detector response was found to be linear in the region of 100–1000 ng/ml. The detection and quantitation limit, as per the error propagation theory, was found to be 50 ng/ml and 100 ng/ml, respectively. The linear equation obtained by the least square regression method was Area = 37.29 × Conc.(ng/ml)?1699.89 with a retention time of 3.97 ± 0.04 min. The results of the analysis were treated statistically, as per ICH guidelines for validation of analytical procedures, USP-2000. and by recovery studies. An internal standard was not employed in the method, as sample recoveries were in good agreement with their label claims. The results were found to be accurate, reproducible, and free from interference. The developed methods were further used for estimation of nimesulide for oral bioavailability of designed sustained release formulations of nimesulide.     

Monitoring Imidazoline Derivatives via Functionalized Nano-Potentiometric Platforms in Aqueous Humor and Dosage Forms

The determination of two imidazoline derivatives [oxymetazoline HCl (OXY) and xylometazoline HCl (XYLO)] was described using different potentiometric platforms. The first electrode type was constructed using tetraphenyl borate (TPB) as anionic exchanger with β-cyclodextrins (β-CD) as ionophore forming oxymetazoline-tetraphenyl borate (OXY-TPB) and xylometazoline-tetraphenyl borate (XYLO-TPB), respectively. The second electrode type was prepared by modification of the first type by conjugation with magnetic iron oxide nanoparticles (MNP) forming (OXY-MNP) and (XYLO-MNP). The synthesized electrodes were fully characterized. The effect of magnetic nano-sized particles as a highly dispersible material with β-CDs on the electrode characteristics was investigated and compared against the classical electrodes. The response time, working pH range and selectivity coefficients were studied. The functionalized nano-electrodes (OXY-MNP and (XYLO-MNP) were found to be more sensitive than the classical electrodes with linearity ranges (1×10⁻⁶–1×10⁻² M). The functionalized nano-electrodes were successfully applied for the in-line analysis of OXY and XYLO in pharmaceutical dosage forms and spiked rabbit aqueous humor samples with no prior extraction of treatment. This suggests the future use of these electrodes in clinical studies of both drugs of interest.     

A Rapid and Simple High Pressure Liquid Chromatographic Method for Pharmacokinetic Study of Ciprofloxacin in Human Serum

Abstract

A rapid, accurate and sensitive method has been developed for the quantitative determination of ciprofloxacin, a new second-generation quinolone carboxylic acid antimicrobial agent, with high in vitro activity against a wide range of Gram- negative pathogens and Gram-positive cocci.

A Lichrosorb RP-18 250 x 4.0 mm, 5 μm analytical column was used with an eluting system consisting of a mixture of CH₃CN-CH₃OH-Citric acid 0.4 M (1:3:6 v/v). Detection was performed with a variable wavelength UV-visible detector at 275 nm resulting in a limit of detection of 0.2 ng per 20 μl injection. For the quantitative determination theophylline was used as chromatographic internal standard at a concentration of 1.56 ng/μl. A rectilinear relationship was observed up to 20 ng/μl. Analysis time was less than 6 min. The statistical evaluation of the method was examined performing intra-day (n=8) and inter-day calibration (n=8) and was found to be satisfactory with highly accurate and precise results. The method was applied to the direct determination of ciprofloxacin in human blood serum. Sample pretreatment involved only protein precipitation with acetonitrile. Recovery of ciprofloxacin in spiked samples was 98 ± 4% over the range of 0.5–5 mg/μl.     

Voltammetric Detector for Liquid Chromatography: Determination of Triclosan in Rabbit Urine and Serum

A flow-electrolytic cell containing a strand of carbon fibers has been designed and characterized for use in a voltammetric detector for high-performance liquid chromatography. The detector was used for determination of triclosan (2,4,4-trichloro-2-hydroxydiphenyl ether) in rabbit serum and urine. Analysis of rabbit serum and urine 1 day and 1 to 5 days, respectively, after ingestion of oral triclosan revealed that the concentration of triclosan was higher than for control serum and urine. The concentration reached maximum levels after 6 h and 34 h or 44 h in serum and urine, respectively. When triclosan was determined in rabbit samples with the method proposed the results obtained were comparable with those obtained by high-performance liquid chromatography with ultraviolet detection.     

离子液体双水相体系萃取分离牛血清白蛋白

建立了由亲水性离子液体四氟硼酸1-甲基-3-丁基咪唑([Bmim]BF4)和KH2PO4形成的双水相体系萃取分离牛血清白蛋白(BSA)的新方法。研究了不同盐及盐的浓度、离子液体浓度以及蛋白质用量、溶液酸度、其它共存物质对双水相成相及BSA萃取率的影响,结果表明,磷酸二氢钾盐浓度为80g/L,离子液体浓度在160~240mL/L,BSA的浓度为30~50mg/L,溶液酸度在pH4~8范围,离子液体双水相体系对BSA有较高的萃取率。用加入不同类型表面活性剂探讨了离子液体与蛋白质之间的作用。     

A Validated RP-LC Method for the Determination of Isosorbide 5-Mononitrate in a Leishmanicidal Ointment

An RP-LC method using a YMC-Pack ODS-AQ column and UV detection (220 nm) was validated for the determination of isosorbide 5-mononitrate selected as an exogenous NO source in a leishmanicidal ointment. After extraction with hot water, the extracts were analysed at 35 °C using isocratic conditions (water-acetonitrile, 4:1 v/v; 0.9 mL min^?1). The method was specific, precise, accurate and linear.     

A Rapid Method for Determination of Progesterone By Reversed-Phase Liquid Chromatography from Aqueous Media

ABSTRACT

A simple reversed-phase liquid chromatographic method to assay progesterone in aqueous receiving medium, following in vitro skin permeation studies is presented. Progesterone was analysed using 5 μm LichroCART® RP-18 column (125 × 4 mm i.d.), after extraction with chloroform. The mobile phase used was methanol:water (70:30) at a flow rate of 1 ml/min. Detection was carried out at 254 nm at room temperature. The method showed a mean recovery of 99% for progesterone, and intra-assay and inter-assay coefficients of variation were below 2%. The proposed method was validated for linearity, specificity, precision and accuracy and showed to be useful for analysis of progesterone in in vitro skin permeation studies.     

2-(5-溴-2-吡啶偶氮)-5-[N,N-二羧基甲基]苯酚光度法测定血清铁

为建立方便、灵敏的血清铁测定法 ,以 2 -(5 -溴 -2 -吡啶偶氮 ) -5 -[N ,N -二羧基甲基 ]苯酚 (5 -Br-PADCAP)作显色剂 ,在pH 6 5HAc-NaAc缓冲液中测定血清铁。结果表明 ,该法线性范围 0～ 5 0 μmol/L ,平均回收率为 99 8% ,批内CV和批间CV分别为 0 0 2 2与0 0 3 2 ,与原子吸收分光光度法比较具有良好的相关性 ,y =0 9942x -0 0 5 7,r =0 990 8,P >0 0 5。 96例健康人血清铁含量为 9 42～ 2 9 86μmol·L- 1(x± 2S)。 5 -Br-PADCAP分光光度法测定血清铁方法简便、灵敏可靠 ,适合临床应用     

Tensiometry as a Simple Analytical Method for Quantification of Solubility and Release of Aroma Molecules in Aqueous Media

Dynamic tensiometry is shown to be a high-potential analytical tool in assessing physico-chemical characteristics of fragrance molecules, such as solubility limit, volatility as well as much rarely assessed interfacial activity of these amphiphilic molecules. Surface tension of aqueous solutions of selected essential oils has been measured as a function of time and fragrance concentration using maximum bubble pressure method. The effect of the temperature and saline solution on the rate of dissolution in water was assessed. Dynamic surface tension turned to be sensitive to the composition of fragrances, as demonstrated on examples of natural and synthetic mixtures. Furthermore, presented work reveals the possibility of maximum bubble pressure tensiometry method to quantify the amount of fragrance compositions in flavored salts, including the artificially aged carrier samples. Suggested here analytical approach can be used for the detection of the purity of essential oils, for the optimization of compositions and of the manufacturing processes of fragrances-containing products, as well as for the assessment of the release/evaporation of fragrances from carrier systems.     

A Validated, Specific, Stability-Indicating RP-LC Method for Analysis of Gatifloxacin in the Presence of Degradation Products and Process-Related Impurities

A validated, specific, stability-indicating reversed-phase liquid chromatographic method has been developed for quantitative analysis of gatifloxacin, its degradation products, and its process-related impurities in bulk samples and in pharmaceutical dosage forms. Forced degradation of gatifloxacin bulk sample was conducted in accordance with ICH guidelines. Acidic, basic, neutral, and oxidative hydrolysis, thermal stress, and photolytic degradation were used to assess the stability-indicating power of the method. Substantial degradation was observed during oxidative hydrolysis. No degradation was observed under the other stress conditions. The method was optimized using samples generated by forced degradation and sample solution spiked with impurities. Good resolution of the analyte peak from peaks corresponding to process-related impurities and degradation products was achieved on a C₁₈ column by use of a simple linear mobile-phase gradient prepared from mixtures of acetonitrile and an aqueous solution of sodium dihydrogen orthophosphate dihydrate and triethylamine adjusted to pH 6.5 with orthophosphoric acid. Detection was performed at 240 nm. Limits of detection and quantification were established for gatifloxacin and its process-related impurities. When the stressed test solutions were assayed by comparison with gatifloxacin working standard the mass balance was always close to 99.3%, indicating the method was stability-indicating. Validation of the method was performed in accordance with ICH requirements. The method was found to be suitable for checking the quality of bulk samples of gatifloxacin at the time of batch release and also during storage.     

Development of a New,Rapid, and Sensitive Validated High-Performance Thin-Layer Chromatographic Method for the Estimation of Berberine in Tinospora cordifolia

JPC – Journal of Planar Chromatography – Modern TLC - A straightforward, delicate, and fast elite thin-layer chromatographic system (high-performance thin-layer chromatography [HPTLC])...     

Rapid and Sensitive RP-LC Method for the Quantification and Pharmacokinetic Study of p-Hydroxyphenethyl Anisate in Rat Plasma

A rapid, sensitive and specific reversed-phase liquid chromatographic method was developed and validated for the quantification of p-hydroxyphenethyl anisate (HPA), which is one of the main constituents of Notopterygium Radix (underground parts of Notopterygium incisum and N. forbesii), in rat plasma, and study its pharmacokinetics after the intravenous administration of 40 mg kg^?1 HPA to rats. The method involves a plasma clear-up step using liquid–liquid extraction by ethyl acetate, followed by RP-LC separation and detection. Separation of HPA was performed on an analytical Diamonsil ODS C₁₈ column equipped with a Dikma ODS C₁₈ EasyGuard column using a mobile phase consisting of MeOH–H₂O (75:25, v/v) at a flow-rate of 1.0 mL min^?1. The UV detection was performed at a wavelength of 256 nm. The linear calibration curves were obtained in the concentration range of 0.05–5.0 μg mL^?1 (r = 0.9992, n = 5) in rat plasma with the lower limit of detection of 0.01 μg mL^?1 and the lower limit of quantification of 0.04 μg mL^?1, and the extraction recovery of HPA was calculated to be the range of 82.01–86.66%. The intra- and inter-day precisions in terms of % relative standard deviation were lower than 2.33 and 3.99% in rat plasma, respectively, with accuracies ranging from 91.22 to 110.5%. The developed method was suitable for the determination and pharmacokinetic study of HPA in rat plasma.     

Spectrophotometric Determination of Nitrite in Aqueous Solution by the Diazotization-Coupling Method with Orthanilic Acid-Resorcinol

Abstract

A spectrophotometric method for the determination of nitrite is described. It relies upon the reaction of this ion with an acidified orthanilic acid solution to form a diazonium ion, which is subsequently coupled with resorcinol, in alkaline medium, to form immediately a yellow-colored stable water-soluble and intense azo dye having maximum absorption at 426 nm. The linear absorbance plot with concentration indicates that Beer's law is obeyed over the range of 1-12 μg of nitrite in a final volume of 10ml, with a molar absorptivity of 38.7 × 10³1 mol^?1cm^?1, sensitivity index of 0.0012μgcm^?3, relative error of –0.5 to +0.2% and relative standard deviation of 0.43-3.5%, depending on the concentration level. The optimum conditions affecting and related to the color reaction and interference due to foreign ions have been studied.     

多沙唑嗪与血清白蛋白的作用及血清中多沙唑嗪含量的荧光测定法研究

用荧光光度法研究了降血压药物多沙唑嗪与血清白蛋白的相互作用,救 是不同温度下药物与血清白蛋白相互作用的形成常数;讨论了微量金属离子对药物与血清白蛋白形成常数的影响,并根据热力学常数确定了该药物与血清白蛋白之间的作用力类型为疏水作用力;研究了多沙唑嗪的适宜条件并成功应用于血样中含量的测定。     

New Rapid Validated HPTLC Method for the Determination of Lycorine in Amaryllidaceae Plants Extracts

A rapid, accurate, specific, repeatable and robust HPTLC method for the determination of lycorine in different Amaryllidaceae plant extracts is presented in this work. No article related to the HPTLC determination of lycorine in plant extracts has been reported in literature. Lycorine, a common alkaloid of family Amaryllidaceae, moreover, there have been some recent reports which reveal the interaction of lycorine with DNA and tRNA. It has, therefore, been to the interest of phytochemists to determine the content of this alkaloid in Amaryllidaceaous plants.     

氢化物电热原子吸收法测定人血清硒

氢化物原子吸收法是原子吸收分光光度法的一个重要分支。笔者应用氢化物电热原子化装置测定血清的硒具有用血量少，成本低，方便简便，精度佳等优点，适合一般医院开展科研和临床测定，采用这种技术可减少试样的基体干扰，提高了分析灵敏度，而且具有良好的线性关系，其测定检出限为1.2μg/L,纯度变异系数为6.3%。     

A Simple and Validated LC Method for the Simultaneous Determination of Three Compounds in Mikania laevigata Extracts

The Mikania genus is widely known as guaco and is used to treat fever, rheumatism, influenza and respiratory diseases. This article deals with the simultaneous quantification of three commercially available phenolic markers (o-coumaric acid, coumarin and syringaldehyde) in M. laevigata extracts, through LC-PDA. The validation data show that the method is specific, accurate, precise and robust, and also indicative of the stability of guaco extract. The method was linear, over a range of 1.25–20.0 μg mL⁻¹ for o-coumaric acid, 2.5–40.0 μg mL⁻¹ for coumarin, and 0.25–4.0 μg mL⁻¹ for syringaldehyde. The range of recovery was 94.3–96.4% for all the components, at a level of 100%.

     

A Validated Stability-Indicating High-Performance Thin-Layer Chromatographic Method for the Estimation of Pirfenidone in Tablet Formulation

JPC – Journal of Planar Chromatography – Modern TLC -     

A Validated Stability-Indicating HPTLC Method for the Estimation of Gemcitabine HCI in its Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - Gemcitabine belongs to a class of drugs known as antimetabolites (pyrimidine analog) used in various carcinomas, such as pancreatic...     

Rapid and Convenient Method for the Determination of Sodium Nitroprusside in Aqueous Solution

Abstract

We propose a rapid and convenient method for the determination of sodium nitroprusside in aqueous solution. In alkaline medium and in the presence of dimethylsulfoxide, the concentration of the nitrite ions coming from the nitroprusside corresponds with the initial quantity of this compound.