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Showing papers in "Journal of analytical and bioanalytical techniques in 2012"


Journal ArticleDOI
TL;DR: The validation parameters are described, together with an example of validation methodology applied in the case of ch romatographic methods used in bioanalysis, taking into account to the recent Food and Drug Administration (FDA) documents.
Abstract: A syntetic discussion on bioanalytical methods vali dation is presented from the point of view of regul atory documents, scientific articles and books. The validation parameters are described, together with an example of validation methodology applied in the case of ch romatographic methods used in bioanalysis, taking i n account to the recent Food and Drug Administration (FDA) gu idelines and documents of the International Confere nce on Harmonisation of Technical Requirements for Registr ation of Pharmaceuticals for Human Use (ICH).

258 citations


Journal ArticleDOI
TL;DR: In this paper, a safe and sensitive method of spectrophotometric estimation in UV-region has been developed for the assay of Paracetamol in its tablet formulation, which does not shows any interference in spectrophotonometric estimations.
Abstract: A novel,safe and sensitive method of spectrophotometric estimation in UV-region has been developed for the assay of Paracetamol in its tablet formulation. The method have been developed and validated for the assay of Paracetamol using Methanol and water as diluents. Which does not shows any interference in spectrophotometric estimations. All the parameters of the analysis were chosen according to ICH [Q2(R1)] guideline and validated statistically using RSD and %RSD along with neat chromate grams.

153 citations


Journal ArticleDOI
TL;DR: Adaptions were made to the FPA to create a low-cost, easier, faster, less labor intensive and less polluting alternative, while maintaining similar results to the standard method.
Abstract: There has been a notable increase in interest about cellulases in recent years due to their numerous potential applications, including the hydrolysis of cellulose in lignocellulosic biomass to produce reducing sugars for the development of second-generation ethanol. However, the traditional cellulase assays are tedious, time-consuming and labor intensive. What is more, they require large amounts of reagents and produce large quantities of toxic effluents? The Filter Paper Assay (FPA) is the standard measure of cellulase activity, according to the International Union of Pure and Applied Chemistry. Although it can be reproduced in most laboratories, with some practice, this method has long been known for its complexity and many manual manipulations. In this study, adaptations were made to the FPA to create a low-cost, easier, faster, less labor intensive and less polluting alternative, while maintaining similar results to the standard method.

55 citations


Journal ArticleDOI
TL;DR: In this article, the diosgenin content was determined from tuber (fresh and dried) and callus of D. alata by acidic hydrolysis of the glycosides and extraction with an organic solvent, followed by HPTLC analysis.
Abstract: Diosgenin, a commercially important bioactive sapogenin, extracted from tubers belonging to Dioscorea species, is used as a precursor in the manufacturing of sex hormones, oral contraceptives and other pharmaceutically important steroidal drugs. Diosgenin content of two Indian variety viz., D. deltoidea and D. prazeri ranges from 0.32 - 1%. With the view to commercially exploit a new source of diosgenin, a lesser explored tuber D. alata Var purpurae (purple yam), from Western Ghats, India was studied. The diosgenin content was determined from tuber (fresh and dried) and callus of D. alata by acidic hydrolysis of the glycosides and extraction with an organic solvent, followed by the HPTLC analysis. HPTLC mobile phase was optimized to toluene: ethyl acetate 7:3 v/v using the PRISMA model and diosgenin content was found to be 0.078, 0.133 and 0.048% respectively after extraction for 8 hrs in alcohol.

37 citations


Journal ArticleDOI
TL;DR: In this article, the reverse phase HPLC method was used for the determination of ursolic acid and betulinic acid from methanol extract of Vitex negundo Linn leaves.
Abstract: Ursolic and betulinic acids are very useful nutraceuticals available in herbs. Their quantitative estimation from the solvent extracts of the herbs is a great challenge. So far all the chromatographic methods available for identification and quantification of these acids are distinctly different, meaning thereby, each acid would require a separate method. Reverse phase (RP-HPLC) method is developed for determination of ursolic acid and betulinic acid from their methanol extract of Vitex negundo Linn leaves. Analysis was carried out using Waters’ symmetry C-18 column with acetonitrile: methanol (80:20) as isocratic elution mode with UV detection (λ=210 nm). The method is pretty linear for ursolic acid in the range of 0.01-0.1 mg/ml (R2 = 0.9961) and for betulinic acid in the range of 0.003-0.018 mg/ml (R2 = 0.999). The peaks of ursolic acid and betulinic acid were confirmed by LC-MS. The method was validated by mixing these acids standards in methanol and found that it is accurate, sensitive and has a good reproducibility.

31 citations


Journal ArticleDOI
TL;DR: In this paper, a simple, precise, accurate, and stability-indicating method was developed and validated for analysis of formoterol fumarate and mometasone furoate in metered dose inhalation formulations.
Abstract: A simple, precise, accurate, and stability-indicating method is developed and validated for analysis of formoterol fumarate and mometasone furoate in metered dose inhalation formulations. Separation was achieved on a reversed-phase C18 column (150 mm×4.6 mm i.d., 5 μm) using a mobile phase consisting of Sodium dihydrogen orthophosphate buffer/acetonitrile (50:50, v/v) at a flow rate of 1.0 mL/min and UV detection at 220 nm. This method is validated according to united States Pharmacopia requirements for new methods, which include accuracy, precision, selectivity, robustness, and linearity and range. This method shows enough selectivity, accuracy, precision, and linearity and range to satisfy Federal Drugs Administration/International Conference on Harmonization regulatory requirements. The current method demonstrates good linearity over the range 0.01-0.20 mg/mL of formoterol fumarate with r2=0.999 and 0.40-6.00 mg/mL of mometasone furoate with r2=0.999. The average recovery of the method is 99.9% of formoterol fumarate with a relative standard deviation of 1.94% and 101.5% of mometasone furoate with a relative standard deviation of 0.81%. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators has proven that the method is robust and rugged.

31 citations


Journal ArticleDOI
TL;DR: These plants extracts with the property of bioavailability and retention of certain minerals by polyphenolic compounds can be recommended for their use as an alternative anti-infective agent in natural medicine for the treatment of infectious diseases.
Abstract: A sensitive and selective high performance liquid chromatography method (HPLC) for simultaneous analysis of following five flavonoids like Gallic acid (GA), Caffeic acid (CA), Rutin (RU), Ferulic acid (FA) and Quercetin (QU) in Amaranthus caudatus (Sirukeerai) leaves. The results demonstrated that the Amaranthus caudatus leaves were separately extracted and analyzed using RP HPLC method. The contents of Gallic acid (0.083 μg/gm), Caffeic acid (0.004 μg/gm), Rutin (0.019 μg/gm), Quercetin (0.001 μg/gm) and Ferulic acid (0.001 μg/gm) in Amaranthus caudatus leaves. The GC-MS study also carried out and it showed the presence of phytochemicals. Hence these plants extracts with the property of bioavailability and retention of certain minerals by polyphenolic compounds can be recommended for their use as an alternative anti-infective agent in natural medicine for the treatment of infectious diseases.

26 citations


Journal ArticleDOI
TL;DR: In this paper, a liquid chromatographic method with UV detection for the simultaneous determination of rosuvastatin, alprazolam and diclofenac sodium in API, pharmaceutical formulations and human serum employing a reversed phase Bondapak C18 column at room temperature using methanol: water (80:20 v/v) and pH adjusted to 2.0 mL.
Abstract: Here, we report a rapid and efficient liquid chromatographic method with UV detection for the simultaneous determination of rosuvastatin, alprazolam and diclofenac sodium in API, pharmaceutical formulations and human serum employing a reversed phase Bondapak C18 (25 cm, 0.46 cm, 10 μm) column at room temperature using methanol: water (80:20 v/v) and pH adjusted to 2.9 with 85% o-phosphoric acid. Separation was achieved within a time span of 6 min. The detector response was monitored at 240 nm and the flow rate was set at 1.0 mL.min -1 . Various LC parameters were optimized and developed method was validated as per ICH (2006) guidelines. Linear calibration range was determined to be 0.02-0.64, 0.125-4.0 and 0.05-1.6 μg.mL -1 and detection and quantitation limits were found to be 4.0, 17.0, 7.0 and 12.0, 52.0, 22.0 ng.mL-1 for rosuvastatin, alprazolam and diclofenic sodium respectively. Method was linear for all analytes with correlation coefficients >0.998. The intra-day and inter-day accuracy and precision of the assay were in acceptable range of 98.21-101.91% recovery and 0.20-2.07% RSD. The sensitivity of the method was enhanced when the chromatograms were analyzed by programming the detector at individual λmax of 244, 222 and 284 nm for rosuvastatin, alprazolam and diclofenac sodium respectively. High peak intensity was observed on injecting same sample concentration after the detector was programmed. Linearity was obtained even at lower concentrations of 0.02-0.64, 0.05-1.60 and 0.02-0.64 μg.mL -1 . LOD and LOQ values shifted down to 3.0, 6.0, 1.0 and 9.0, 19.0, 3.0 ng.mL -1 respectively. Recovery was found to be in the range of 98.32-101.87% and inter-day and intra-day precision was less than 2.10%. The proposed method was found to be robust and successfully employed for the determination of studied drugs in commercial formulations and human serum without interference of excipients or endogenous components of serum.

20 citations


Journal ArticleDOI
TL;DR: In this paper, an HPLC method for determination of lumefantrine in human plasma was used to assess three medical university laboratories of Tanzania, Uganda and Kenya, and the results from MUHAS Bioanalytical laboratory (Tanzania) Laboratory met the criteria set by ACC laboratory.
Abstract: Background: Bioanalytical laboratories in developing countries face many challenges. The objective of this work was to assess the capacity of bioanalytical laboratories in emerging countries in setting and validating analytical methods. An HPLC method for determination of lumefantrine in human plasma was used to assess three medical university laboratories of Tanzania, Uganda and Kenya. Methodology: Bioanalytical experts from Analytical Clinical Concept, Leidersbach, in Germany (ACC GmbH) developed the HPLC method and assigned the 3 laboratories to set up and validate the method. The laboratories were tasked to determine the concentrations of blinded plasma samples spiked with lumefantrine and had to submit their analysis reports to ACC for evaluation within 6 weeks. Each laboratory was provided with reference standard, internal standard columns and precolumns. Spiked plasma samples were shipped under dry ice from Germany to “Gesellschaft fuer Internationale Zusammenarbeit” (GIZ) local office of each participating country. All other requirements were procured by individual laboratories. Results: The results from MUHAS Bioanalytical laboratory (Tanzania) Laboratory met the criteria set by ACC laboratory. The results were within the range set by ACC laboratory and most calibration curves had good linearity with coefficient of correlation always > 0.990. The inter-day precision and accuracy (Relative standard deviation=RD of recovery) were always < 15%. The relative deviation of the results obtained compared to assigned concentrations for blinded plasma samples were between -15% and -25%. The Laboratory met the stipulated time line and the obtained validation results were within the range set by the ACC experts. The results from other laboratories were also satisfactory. Conclusion: The results indicate that with further little infrastructural and technical assistance the capacity of these bioanalytical laboratories in conducting bio-analyses will be more strengthened and can serve as centers for training bioanalytics and running bioequivalence studies in the region.

18 citations


Journal ArticleDOI
TL;DR: Validation according to FDA guidelines for bioanalysis indicates that the described UHPLC-HESI-MS/MS method provides rigorous quantification of acyclovir in human plasma and representative data demonstrates successful application towards the determination of pharmacokinetic profiles as part of an evaluation of drug formulation bioequivalence.
Abstract: Pharmacokinetic studies are essential towards determining bioequivalence and establishing pharmacokinetic profiles for drug moieties requires accurate quantification. We report a rapid, sensitive, and robust method for the determination of acyclovir in human plasma and its validation towards evaluating the bioequivalence of drug formulations. After a simple liquid-liquid extraction from plasma, acyclovir is quantified using ultra-high-performance liquid chromatography - heated electrospray ionization - tandem mass spectrometry (UHPLC-HESI-MS/MS). The assay has a total analysis time is 5 min, a linear range of 1.0 - 2000 ng/mL, a lower limit of detection of 0.5 ng/mL, and a lower limit of quantification of 1.0 ng/mL. Intra- and inter-day precision is no more than 10.3% and intraand inter-day accuracy was within 13% at various concentrations in human plasma. Validation according to FDA guidelines for bioanalysis indicates that the described UHPLC-HESI-MS/MS method provides rigorous quantification of acyclovir in human plasma and representative data demonstrates successful application towards the determination of pharmacokinetic profiles as part of an evaluation of drug formulation bioequivalence.

16 citations


Journal ArticleDOI
TL;DR: In this article, a simple reversed phase HPLC method has been successfully developed and validated for the quantitative determination of enalapril maleate (ENP) in bulk material, pharmaceutical formulation and serum.
Abstract: A simple reversed phase HPLC method have been successfully developed and validated for the quantitative determination of enalapril maleate (ENP) in bulk material, pharmaceutical formulation and serum. Purospher Start C 18 (250 cm x 4.6 mm, 5 μm) and Hypersil, ODS columns were used. The mobile phase, methanol-acetonitrile-water (70:30v/v pH 3.5 adjusted by phosphoric acid), was delivered at a flow rate of 1 mLmin -1 , eluent was monitored using UV detector at 215 nm. The proposed method is specific, accurate (99-102%), precise (intra-day and inter-day variation 0.07-1.25%) and linearity (R 2 >0.999) within the desired range 2.5-100 μgmL -1 concentration. The detection limit and quantification 3.9 ngmL -1 and 12 ngmL -1 respectively. The anticipated method is applicable to routine analysis of ENP in pharmaceutical formulations as well as in human serum samples.

Journal ArticleDOI
TL;DR: A simple and sensitive HPLC method with fluorescence detection for quantitation of telmisartan in rabbit plasma was developed and validated in this paper, where the linearity range of the proposed method was 4 to 375 ng/mL.
Abstract: A simple and sensitive High-Performance Liquid Chromatography (HPLC) method with fluorescence detection for quantitation of telmisartan in rabbit plasma was developed and validated. Separation of telmisartan from plasma components was achieved on a Chromolith RP18e column (100 x 4.6 mm 5 μ). Losartan was used as an internal standard. A mobile phase consisting of 50 mM sodium phosphate buffer and acetonitrile in the volume ratio of 65:35 v/v was delivered at a flow rate of 3.5 mL/min. A simple and rapid sample preparation involved solid phase extraction using Varian Bond Elute C-18 cartridge. The linearity range of the proposed method was 4 to 375 ng/mL. The intra-day and inter-day coefficients of variation obtained for telmisartan were less than 4.90% and relative error was less than 9.08%. The overall recoveries for telmisartan and losartan were 101.7% and 100.0%, respectively. This validated method was used successfully for analysis of plasma samples from a pharmacokinetic study.

Journal ArticleDOI
TL;DR: Chitin is a natural biopolymer with a chemical structure similar to that of cellulose and is a major component of the exoskeleton of invertebrates and therefore, crustacean waste is ideal as raw material for chitin production.
Abstract: α-, β-, and γ- forms exist with different chitin microfibril orientations. The α-form has antiparallel chains and is the most abundant in nature. It occurs in the shells of crustaceans (crabs, shrimp, lobsters, etc.), in the shells and skeletons of mollusks and krill, insects, etc., and in the cell walls of fungi (mushrooms, bakers’ yeast, etc.). The β-form has parallel chains and is rare in the nature. It occurs in squid pens, in the extracellular spines of the euryhaline diatom, and in pogonophore tubes. The γ-form has a mixture of anti parallel and parallel chains and is found in the cocoons of insects [8]. Chitin is a natural biopolymer with a chemical structure similar to that of cellulose and is a major component of the exoskeleton of invertebrates. Therefore, crustacean waste is ideal as raw material for chitin production. The extracted chitin can be used to produce chitin derived products, such as chitosans, chito-oligosaccharides and glucosamine, but also for bioplastic production. The interest to use chitinous products in foods and pharmaceuticals is increasing due to their broad range of industrial applications [9,10].

Journal ArticleDOI
TL;DR: In this article, a simple, rapid, precise and highly accurate RP-HPLC method was developed and validated for determination of alpha-mangostin content extracted from PLGA-microspheres.
Abstract: A simple, rapid, precise and highly accurate RP-HPLC method was developed and validated for determination of alpha-mangostin content extracted from PLGA-microspheres. Method was developed using a silica-based deactivated C-18 column (4.6×100 mm, 3 μm) with a mobile phase of 70-80 % v/v acetonitrile (A) and 0.1% v/v orthophosphoric acid (B), with the following pre-determined timed-gradient program: 70% (A) isocratic for 6 min, 70-75% (A) in 1.2 min, 75-80% (A) in 0.4 min, 80% (A) isocratic for 2.4 min, 80-70% (A) in 0.4 min, finally 70% (A) isocratic for 5 min, with a flow rate of 1 mL/min, detected at 320 nm by a UV detector. Linearity was obtained over the range of 1-200 μg/mL with r 2 =0.9995. The precision was achieved based on repeatability and intermediate precision with RSD of 0.13-0.6% and 0.57-1.2%, respectively. Percent recovery of 100.55% to 103.82% with RSD 0.086 - 0.15 implied high accuracy of the method. Limit of detection and limit of quantitation were 0.038 and 0.121 μg/ml, respectively suggesting good sensitivity of the method. The method is envisaged to be effectively used for routine quality control assay for encapsulated alpha-mangostin in PLGA microspheres.

Journal ArticleDOI
TL;DR: A facile, accurate, sensitive and validated spectrophotometric method for the determination of zolmitriptan (ZMT) in pure and dosage forms is described in this article.
Abstract: A facile, accurate, sensitive and validated spectrophotometric method for the determination of zolmitriptan (ZMT) in pure and dosage forms is described. The methods are based on the formation of charge transfer reactions between ZMT and chromogenic reagents 7,7,8,8-tetracyanoquinodimethane (TCNQ); p-chloranilic acid (P-CLA), quinalizarin (Quiz) and alizarin red S (ARS) producing charge transfer complexes which showed an absorption maximum at 840, 532, 554 and 534 nm for TCNQ, P-CLA, Quiz and ARS, respectively. The optimization of the reaction conditions such as the type of solvent, reagent concentration and reaction time were investigated. Beer’s law is obeyed in the concentration ranges 1.0-140 μg mL -1 . The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was ≥0.9991 (n=6) with a relative standard deviation (R.S.D.) of ≤ 1.01. The proposed methods were successfully applied for simultaneous determination of zolmitriptan in tablets with good accuracy and precision and without interferences from common additives and the validity assesses by applying the standard addition technique, which compared with those obtained using the reported method.

Journal ArticleDOI
TL;DR: A stability indicating HPLC assay with UV detection was developed to allow simultaneous detection of the active pharmaceutical ingredient (Gentamicin Sulfate) and the primary excipient (L-leucine) and validation data indicated that the dual detection assay meets or exceeded all criteria for use as a stability indicating assay.
Abstract: TM ; Dual de- tection; Dry powder; Inhalation Abstract A stability indicating HPLC assay with UV detection was developed for the simultaneous quantification of Gentamicin Sulfate and L-leucine from NanoGENT™ dry powder for inhalation. In order to support the development of the NanoGENT™ (dry powder Gentamicin Sulfate for inhalation) the assay was created to allow simultaneous detection of the active pharmaceutical ingredient (Gentamicin Sulfate) and the primary excipient (L-leucine). In order to quantify Gentamicin Sulfate by UV detection derivatization was required. The assay resolved L-leucine from all four Gentamicin Sulfate peaks and all four Gentamicin Sulfate peaks from each other with a reversed phase isocratic assay. Once developed the assay was validated in accordance with regulatory guidance in order to support regulatory approval of the NanoGENT™ dry powder inhalation formulation. The validation data indicated that the dual detection assay meets or exceeded all criteria for use as a stability indicating assay. Orally inhaled therapeutics are a mainstay in the treatment of asthma and COPD and is growing rapidly in the treatment of other pulmonary and systemic indications. The growth of orally inhaled therapeutics to treat atypical indications has broadened beyond vaccines and insulin to include biological threats. This growth has exacerbated the fact that there are currently a minimal number of GRAS excipients for inhalation delivery (1). Further, the excipients that are considered GRAS do not span the range of physical chemical properties that are often required for formulations of a material for delivery to the lungs.

Journal ArticleDOI
TL;DR: A new sample preparation extraction method analysis assay has been explored to enable future high-throughput, reproducible, and sensitive assays for the extraction of galanthamine in guinea pig plasma.
Abstract: Galanthamine hydrobromide (GAL HBr), approved material for treatment of mild to moderate Alzheimer’s disease, is a centrally-acting reversible acetylcholinesterase inhibitor (AChEI) that is currently under evaluation as a therapeutic countermeasure against organophosphorus G- and V-Series nerve agents, which can induce rapid lethality in guinea pigs and humans. It has been shown that upon combination with atropine (ATR) and pyridine-2-aldoxime methochloride (2-PAM), a single dose of GAL administered before or soon after the acute exposure to a lethal dose of organophosphorus compounds can safely counteract toxicity in guinea pigs. To that end a new sample preparation extraction method analysis assay has been explored to enable future high-throughput, reproducible, and sensitive assays for the extraction of galanthamine in guinea pig plasma. Samples were prepared with diphenhydramine hydrochloride (DPH HCl) internal standard and recovered with 10 min liquid-liquid trichloromethane extractions. Samples were analyzed with a reversed phase liquid chromatographic column interfaced to a triple quadrupole mass spectrometer (LC/MS/MS) operating in the positive ion multiple reaction monitoring (MRM) Turbo Ionspray mode. Precursor to product ion (M+H)+ transitions of 288-to-213 m/z and 256-to-167 m/z for GAL and DPH were observed, respectively. Sample run times of 1.50 min were achieved.

Journal ArticleDOI
TL;DR: In this article, a simple, precise, rapid and accurate Reverse phase HPLC method was developed for the estimation of Dapiprazole in bulk form using a Thermo hypersil C-18 column (250 mm×4.6 mm 5μm) with mobile phase consisting of mixture of methanol: acetonitrile: and ortho-phosphoric acid in the ratio of 89: 9: 1 (v/v).
Abstract: A simple, precise, rapid and accurate Reverse phase HPLC method was developed for the estimation of Dapiprazole in bulk form. A Thermo hypersil C-18 column (250 mm×4.6 mm 5μm) with mobile phase consisting of mixture of methanol: acetonitrile: and ortho-phosphoric acid in the ratio of 89: 9: 1 (v/v) at pH 5.8 adjusted with ortho-phosphoric acid. The flow rate was 0.8 mL/min and the effluents were monitored at 243 nm. The retention time was 3.725 min. The detector response was linear in the concentration of 20-120 μg/mL. The respective linear regression equation being y=1956.4x+3409. The limit of detection and limit of quantification was 0.5 μg/mL and 1.6 μg/mL respectively. The percentage assay of Dapiprazole was 99.94%. This method has been validated and shown to be specific, sensitive, precise, linear, accurate, rugged, robust and fast. Hence, this method can be useful for the routine determination of Dapiprazole in bulk drug and in its pharmaceutical dosage form.

Journal ArticleDOI
TL;DR: Urine drug testing, using LC-MS/MS technology with validated cutoff values for each analyte, provides objective data for providers to use when assessing medication use, potential drug-drug interactions, potential adverse events, and possible diversion.
Abstract: Background: Patients on chronic opioid therapy are often closely monitored to identify prescribed or nonprescribed medications and/or illicit substances and to identify medication use that may lead to adverse events. Monitoring is typically performed using a combination of clinical tools and assessment methods that often include patient medication histories, risk assessments, and medication monitoring with urine testing. The chronic pain population may be prescribed an average of three to five medications for pain and associated symptoms. In addition to prescribed therapies, this patient population often takes non-prescribed medications and/or illicit substances. Medication monitoring with Urine Drug Testing (UDT), particularly when performed using mass spectrometry, provides accurate information about medications and illicit substances present in the urine. Purpose of the study: To use LC-MS/MS analyses to describe the variety of medications and metabolites observed in urine specimens from individuals on opioid therapy. Methods: Analytical procedures were developed using LC-MS/MS that could detect and differentiate between various opioids and their metabolites, other medications commonly prescribed for pain, and certain illicit substances. This retrospective analysis used approximately 340,000 de-identified specimens tested between November 2011 and February 2012 at Millennium Laboratories. Data was sorted to determine frequency of detection and concentrations of the excreted drugs and metabolites. Results: The most frequently observed medications were hydrocodone and oxycodone, and their metabolites. The next most frequently observed medication was the benzodiazepine class followed by gabapentin, buprenorphine, and morphine. Additionally, illicit substances were detected in 15% of specimens; the most common illicit substances were cannabinoids and cocaine. Conclusions: Urine drug testing, using LC-MS/MS technology with validated cutoff values for each analyte, provides objective data for providers to use when assessing medication use, potential drug-drug interactions, potential adverse events, and possible diversion. Specific identification of both the medication or substance and the associated metabolites allows for informed interpretation of UDT results. Understanding the medications and illicit substances found in UDT specimens from the pain population helps providers optimize medication monitoring for the best possible plan for pain management.

Journal ArticleDOI
TL;DR: In this paper, the authors studied the reversible thermoresponsivity of poly(n-isopropylacrylamide) (pNIPAm) in water and showed that when the polymer is heated > 31°C, it transits from a random coil to a globule conformation.
Abstract: Poly (N-isopropylacrylamide) (pNIPAm) is one of the most completely studied “smart” polymers due to its unique reversible thermoresponsivity. That is, when pNIPAm in water is heated > ~31°C, it transits from a random coil to a globule conformation; this transition is reversed when T < ~31°C. This conformational change is accompanied by water exchange process. When pNIPAm undergoes the coil to globule transition, water is expelled, while water is “sorbed” when the polymer undergoes the opposite process.

Journal ArticleDOI
TL;DR: It's not surprisingly when entering this site to get the book, the popular book now is the advanced polymer composites and searching for this popular book in this website will give you benefit.
Abstract: It's not surprisingly when entering this site to get the book. One of the popular books now is the advanced polymer composites. You may be confused because you can't find the book in the book store around your city. Commonly, the popular book will be sold quickly. And when you have found the store to buy the book, it will be so hurt when you run out of it. This is why, searching for this popular book in this website will give you benefit. You will not run out of this book.

Journal ArticleDOI
TL;DR: This labeling protocol offered greater sensitivity than the more conventional pre-column labeling protocol (with a 10-fold lower limit of detection for HSA with bis-SQHN-4d), and is well suited to the development of other protein assays.
Abstract: Labeling proteins with fluorescent dyes offers a powerful tool for monitoring protein interactions in vitro and in vivo. In order for this tool to be effective, the nature of the dyes - absorbance and emission properties, solution stability, pH range, and mechanisms for protein interaction - must first be considered. Two new asymmetric, squarylium dyes, bis-SQHN-4d and SQHN-3c, were shown to be only weakly fluorescent in aqueous buffers in the absence of proteins. However, their spectra showed a dramatic increase in fluorescence intensity upon the addition of Human Serum Albumin (HSA) or Bovine Serum Albumin (BSA) as model proteins. The enhanced fluorescence properties, attributed to noncovalent binding, allowed the use of the new squarylium dyes as probes for the low-level detection of proteins in a mixture (including myoglobin (pI=7.16), transferrin (pI=5.9), and HSA (pI=4.8)), separated by Capillary Electrophoresis with Laser-Induced Fluorescence detection (CE-LIF). Because of the low background fluorescence of these probes, on-column labeling was feasible and led to simple and rapid protein detection. This labeling protocol offered greater sensitivity than the more conventional pre-column labeling protocol (with a 10-fold lower limit of detection for HSA with bis-SQHN-4d). A limit of detection for HSA (by CE-LIF with on-column labeling with bis-SQHN-4d) of 3.42 x 10-8 M indicates that this dye is well suited to the development of other protein assays.

Journal ArticleDOI
TL;DR: By using NMR spectroscopy, this work attempted to differentiate blood plasma from infected patients from healthy subjects and afterwards identify the consistent changes, several of which were found and are discussed.
Abstract: Dengue is a very common viral disease in tropical countries. From time to time it has become epidemic, hindering economics and affecting the social system. Early starting treatment reduces recovery time and suffering of the patients. But, the usual diagnostics is done by detection of the antibodies, which can only be done after five days. Other parts of the metabolomics might change much faster and therefore the small molecule content in the blood might change much faster than that. By using NMR spectroscopy we attempted to differentiate blood plasma from infected patients from healthy subjects and afterwards identify the consistent changes. Several of these were found and are discussed.

Journal ArticleDOI
TL;DR: This review will briefly attempt to focus on the most current classifications and emerging trends in LC-MS instrumentation and their respective contributions to the field of analytical and bioanalytical techniques.
Abstract: With recent advancement in instrumentation from a variety of researchers and manufactures the use of liquid chromatography (LC) and mass spectrometry (MS) has become a powerful twodimensional (2D) hyphenated technology for the use in a wide assortment of analytical and bioanalytical techniques for the analysis of nucleic acids, amino acids, peptides, proteins, carbohydrates, lipids, and etcetera [1-3] and/or in the main classification of omics fields such as genomics, proteomics, metabolomics, lipidomics, and etcetera [47]. This advancement in LCMS was originally and still is fueled by the need for more powerful analytical and bioanalytical techniques that can accurately and precisely discriminate target analytes from high complexity mixtures in a sensitive and selective way. With this in mind, this review will briefly attempt to focus on the most current classifications and emerging trends in LC-MS instrumentation and their respective contributions to the field of analytical and bioanalytical techniques.

Journal ArticleDOI
TL;DR: In this paper, two solid states were observed in cefpiramide: a crystalline form and an amorphous one, and both the accelerated (40°C ± 2°C /75% ± 5% relative humidity (RH)) and stress (60°C−2°C/75%−5% RH) stability study demonstrated that the crystalline version of cefpamide was much more stable than its amorphusous form, with related substances, high molecular mass polymers and assay parameters indicating parameters.
Abstract: Cefpiramide is susceptible to many factors, including high temperature. Two solid states were observed in cefpiramide: a crystalline form and an amorphous one, and both the accelerated (40°C ± 2°C /75% ± 5% relative humidity (RH)) and stress (60°C ± 2°C / 75% ± 5% RH) stability study demonstrated that the crystalline form of cefpiramide was much more stable than its amorphous form, with related substances, high molecular mass polymers and assay as critical stability indicating parameters. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and water content results indicated that each molecule of crystalline cefpiramide may contain two molecules of crystal water, which can explain its high thermal stability. This study provides valuable information for cefpiramide and its drug products with respect to the improvement of its thermal stability through crystallization.

Journal ArticleDOI
TL;DR: In this paper, the degradation of chelates viz., NTA, EDTA and DTPA at 313 K temperature, pH 6, Iron concentration 10000 ppm and Fe-Chelate molar ratio 1:2.
Abstract: Oxidative absorption of hydrogen sulfide into a solution of ferric chelate is studied in stirred cell glass reactor. The experiments are performed to investigate degradation of chelates viz., NTA, EDTA and DTPA at 313 K temperature, pH 6, Iron concentration 10000 ppm and Fe-Chelate molar ratio 1:2. Oxidative absorption of hydrogen sulfide into a solution of Fe-NTA was found better. Therefore, further experiments with 10%, 50% and 100% concentrations of hydrogen sulfide are performed. It is observed that this process is applicable for removal of low to high concentrations of hydrogen sulfide. Effect of antioxidant using sodium thiosulphate is also studied in order to minimize degradation of NTA. The kinetic parameters are studied and it is observed that the reaction appeared to be first order in ferric chelate and Rate constant values for 100%, 50% and 10% hydrogen sulfide concentration are 0.035 hr-1, 0.013 hr-1 and 0.019 hr-1 respectively.

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TL;DR: In this article, the cellulose rich biomass of Sorrel was graft copolymerized by vinyl monomeric mixtures and used as reinforcement in phenol-formaldehyde polymer matrix based green composite.
Abstract: In this research paper, the cellulose rich biomass of Sorrel was graft copolymerized by vinyl monomeric mixtures. The graft copolymers were characterized by advanced analytical techniques like FTIR, SEM, XRD, TGA and DTA techniques and evaluated for physico-chemical changes in the properties of the modified fiber. With increase in the percentage grafting a significant physico-chemico-thermal resistance were observed. Miscibility in organic solvents, hydrophobicity were found to increase whereas crystallinity, crystallinity index, dye-uptake and hydrophylicity decreased after graft copolymerization, however, the cellulose form I remained unchanged. These graft copolymers were then used as reinforcement in phenol-formaldehyde polymer matrix based green composite. They were then characterized and evaluated for their physico-chemico-thermo-mechanical competence. The use of graft copolymers as reinforcement in polymer matrix is the best technique to procure green composite. The novelty of the work lies in the use of renewable waste biomass to procure the advanced material. These advanced materials could serve as pioneer for scientific and industrial applications.

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TL;DR: In this article, an inexpensive, highly robust, sensitive assay for inhibitors of the tumor necrosis factor alpha interaction with the 55 kD receptor (TNFR 1 ) has been developed that does not require modification of TNF-alpha.
Abstract: The over-expression of tumor necrosis factor alpha (TNF-alpha) has been associated with various diseases, particularly autoimmune diseases such as rheumatoid arthritis and Crohn’s disease. Some biologic therapies for these diseases specifically target this cytokine, sequestering it, and preventing its interaction with its 55 kD receptor (TNFR 1 ). While these therapies have proven the validity of this approach, they are large proteins that require intravenous administration. Small molecule inhibitors of this interaction are highly desirable and some have been developed. However, such inhibitors have not been reported to have successfully completed clinical trials. One prohibition to this approach is the current state of in vitro testing of such molecules. Assays have been developed that use radio labeled or biotin labeled TNF-alpha. In vivo methods exist, but are cost prohibitive to screening a large selection of molecules. Reported here-in is an inexpensive, highly robust, sensitive assay for inhibitors of the TNF- alpha interaction with TNFR 1 that does not require modification of TNF-alpha. The simplicity of this assay should allow for increased investigation into inhibiting this important interaction.

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TL;DR: This method provides excellent sensitivity and visualization of fascaplysin as a single peak allowing for rapid analysis of plasma samples involving absorption, distribution, and metabolism studies and validated by parameters including good linear correlation and good precision.
Abstract: Fascaplysin is a cytotoxic natural product isolated from a variety of Indo-Pacific marine organisms, primarily Fascaplysinopsis sponges and Didemnum tunicates. Positive xenograft studies involving this alkaloid structural class have indicated that fascaplysin may serve as an important lead compound for preclinical development. This study was undertaken as a prelude to a full pharmacokinetics and therapeutic assessment of fascaplysin. We describe here a simple plasma preparation and a rapid HPLC method for the detection of fascaplysin in mice. The method was validated by parameters including good linear correlation, a limit of quantification of 107.1 μg/mL, and a good precision with a coefficient of variation of 0.92% for 10 μg/mL. This method provides excellent sensitivity and visualization of fascaplysin as a single peak allowing for rapid analysis of plasma samples involving absorption, distribution, and metabolism studies. A preliminary pharmacokinetics study in C57Bl/6 mice using 20.6 mg/kg fascaplysin yielded a biphasic curve with T½α=16.7 min, T½β=11.7 h, and C0 of 17.1 μg/mL.

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TL;DR: In this paper, a multicomponent spectrophotometric method for simultaneous estimation of Metaxalone and Diclofenac Potassium in combined tablet dosage form had been proposed.
Abstract: A simple Multicomponent Spectrophotometric method for simultaneous estimation of Metaxalone and Diclofenac Potassium in combined tablet dosage form had been proposed. Considering the absorption spectra of both analytes in the range of 220-350 nm in methanol, the four wavelengths of equal intervals of 40 nm were selected as 350 nm, 310 nm, 270 nm and 230 nm to produce calibration curves of mixture of analytes. The present method used inbuilt application of instrument (Shimadzu Pharm Spec 1700, UV spectrophotometer) to quantify Metaxalone and Diclofence potassium in formulation. The method had been validated in accordance with ICH guidelines for accuracy and precision.