| 1. |
- Abdel-Rehim, Abbi, et al.
(författare)
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Dried saliva spot as a sampling technique for saliva samples
- 2014
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 28:6, s. 875-877
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, dried saliva spot (DSS) was used as a sampling technique for saliva samples. In the DSS technique 50 L of saliva was collected on filter paper and the saliva was then extracted with an organic solvent. The local anesthetic lidocaine was used as a model compound, which was determined in the DSS using liquid chromatography and mass spectrometry. The results obtained for the determination of lidocaine in saliva using DSS were compared with those from a previous study using a microextraction by packed sorbent syringe as the sampling method for saliva. This study shows that DSS can be used for the analysis of saliva samples. The method is promising and very easy in terms of sampling and extraction procedures. The results from this study are in good agreement with those from our previous work on the determination of lidocaine in saliva. DSS can open a new dimension in the saliva handling process in terms of sampling, storing and transport.
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| 2. |
- Abdel-Rehim, Abbi, et al.
(författare)
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Evaluation of microextraction by packed sorbent and micro-liquid chromatography-tandem mass spectrometry as a green approach in bioanalysis
- 2013
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 27:10, s. 1225-1233
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Tidskriftsartikel (refereegranskat)abstract
- In this study the use of micro-liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was investigated in routine bioanalysis application for separation and quantification of pro-drug AZD6319 (developed for aldezheimer treatment). Microextraction by packed sorbent (MEPS) was used as sample clean-up method. The focus of this study was put on the evaluation of the usability of smaller column diameters such as 1.0 and 0.3mm instead of 2.1mm in bioanalysis application to reduce solvent consumption and sample volumes. Solvent consumption was reduced by 80% when a 1.0mm column was used compared with 2.1mm column. Robustness of the micro-columns in terms of accuracy and precision was investigated. The application of LC-MS/MS for the quantitative analysis of AZD6319 in plasma samples showed good selectivity, accuracy and precision. The coefficients of determination (R-2) were >0.998 for all runs using plasma samples on the studied micro-columns. The inter-day accuracy values for quality control samples ranged from 99 to 103% and from 96 to 105% for 0.3x50mm and 1.0x50mm columns, respectively. The inter-day precision values ranged from 4.0 to 9.0% and from 4.0 to 8.0% for 0.3x50 and 1.0x50mm columns, respectively. In addition the sensitivity was increased by three times using a 1.0mm column compared with 2.1mm. Furthermore, robustness of the micro-columns from different manufacturers was investigated.
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| 3. |
- Abdel Rehim, Abbi, et al.
(författare)
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Screening and determination of drugs in human saliva utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry
- 2013
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 27:9, s. 1188-1191
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C-8-cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS-LC-MS/MS is reported.
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| 4. |
- Abohalaka, Reshed, et al.
(författare)
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The effects of systemic and local fatty acid amide hydrolase and monoacylglycerol lipase inhibitor treatments on the metabolomic profile of lungs.
- 2022
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Ingår i: Biomedical chromatography : BMC. - : Wiley. - 1099-0801 .- 0269-3879. ; 36:1
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of the endocannabinoid system to both physiology and pathological processes in the respiratory system makes it a promising target for inflammatory airway diseases. Previously, we have shown that increasing the tissue endocannabinoid levels by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) inhibitors can prevent airway inflammation and hyperreactivity. In this study, the changes in the levels of major metabolites of endocannabinoids by systemic and local FAAH or MAGL inhibitor treatments were evaluated. Mice were treated with either the FAAH inhibitor URB597 or the MAGL inhibitor JZL184 by local (intranasal) or systemic (intraperitoneal) application. Bronchoalveolar lavage (BAL) fluids and lungs were isolated afterward in order to perform histopathological and metabolomic analyses. There were no significant histopathological changes in the lungs and neutrophil, and macrophage and lymphocyte numbers in BAL fluid were not altered after local and systemic treatments. However, GC-MS-based metabolomics profile allowed us to identify 102 metabolites in lung samples, among which levels of 75 metabolites were significantly different from the control. The metabolites whose levels were changed by treatments were mostly related to the endocannabinoid system and energy metabolism. Therefore, these changes may contribute to the anti-inflammatory effects of URB597 and JZL184 treatments in mice.
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| 5. |
- Alizadeh, R., et al.
(författare)
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Synthesis of Depo-Medrol-chitosan hydrogel as new drug slow-release appliance and investigation of release kinetics by high-performance liquid chromatography
- 2016
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Ingår i: Biomedical Chromatography. - : Wiley. - 1099-0801 .- 0269-3879. ; 30:9, s. 1346-1353
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Tidskriftsartikel (refereegranskat)abstract
- The present study deals with preparation and optimization of a novel chitosan hydrogel-based matrix by suspension cross-linking method for controlled release of Depo-Medrol. The controlled release of Depo-Medrol for effective Rheumatoid arthritis disease has become an imperative field in the drug delivery system. In this context, it was intended to optimize loading circumstances by experimental design and also study the release kinetics of Depo-Medrol entrapped in the chitosan matrix in order to obtain maximal efficiency for drug loading. The optimum concentrations of chitosan (2.5g), glutaraldehyde (3.05L) and Depo-Medrol (0.1mg) were set up to achieve the highest value of drug loaded and the most sustained release from the chitosan matrix. In vitro monitoring of drug release kinetic using high-performance liquid chromatography showed that 73% of the Depo-Medrol was released within 120min, whereas remained drug was released during the next 67h. High correlation between first-order and Higuchi's kinetic models indicates a controlled diffusion of Depo-Medrol through the surrounding media. Moreover, recovery capacity >82% and entrapment efficiency of 58-88% were achieved under optimal conditions. Therefore, the new synthesized Depo Medrol-chitosan is an applicable appliance for therapy by slow release mechanism.
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| 6. |
- Ashri, Nadia Y., et al.
(författare)
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micMicroextraction by packed sorbent and liquid chromatography-tandem mass spectrometry as a tool for quantification of peptides in plasma samples : determination of sensory neuron-specific receptors agonist BAM8-22 and antagonist BAM22-8 in plasma samples
- 2013
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 27:3, s. 396-403
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Tidskriftsartikel (refereegranskat)abstract
- Microextraction by packed sorbent (MEPS) is a miniaturized, solid-phase extraction (SPE) technique that works online with gas chromatography (GC) and liquid chromatography (LC). Not only is the automation process with MEPS advantageous, but the much smaller volumes of the samples, solvents and dead space in the system also provide other significant advantages such as the speed and the simplicity of the sample preparation process. In this study MEPS has been evaluated for quantification of sensory neuron-specific receptors agonist (BAM8-22). Owing to the instability of BAMs, the focus was on fast extraction and determination of the peptide online using LC-MS/MS. Sorbents such as C2, C8 and ENV+ (hydroxylated polystyrenedivinylbenzene copolymer) were investigated in the present study. MEPS-C8 gave the best results compared with C2 and ENV and it was used for the method validation. The calibration curve was obtained within the concentration range of 20.03045nmol/L in plasma. The regression correlation coefficients for plasma samples were 0.99 for all runs (n=6). The between-batch accuracy and precision for BAM8-22 ranged from 13 to 2.0% and from 4.0 to 14%, respectively. Additionally, the accuracy and precision for BAM22-8 ranged from 13 to 7.0% and from 3.0 to 12%, respectively. The present method was used for pharmacokinetic studies for BAMs in plasma samples.
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| 7. |
- Aslıyüce, Sevgi, et al.
(författare)
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Combined protein A imprinting and cryogelation for production of spherical affinity material
- 2019
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 33:10
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Tidskriftsartikel (refereegranskat)abstract
- Cryogels have been demonstrated to be efficient when applied for protein isolation. Owing to their macroporous structure, cryogels can also be used for treating particle-containing material, e.g. cell homogenates. Another challenging development in protein purification technology is the use of molecularly imprinted polymers (MIPs). These MIPs are robust and can be used repeatedly. The paper presents a new technology that combine the formation of cryogel beads concomitantly with making imprints of a protein. Protein A was chosen as the print molecule which was also be the target in the purification step. The present paper describes a new method to produce protein-imprinted cryogel beads. The protein-imprinted material was characterized and the separation properties were evaluated with regard to both the target protein and whole cells with target protein exposed on the cell surface. The maximum protein A adsorption was 18.1 mg/g of wet cryogel beads. The selectivity coefficient of protein A-imprinted cryogel beads for protein A was 5.44 and 12.56 times greater than for the Fc fragment of IgG and protein G, respectively.
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| 8. |
- Bienvenu, Emile, et al.
(författare)
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A rapid and selective HPLC-UV method for the quantitation of efavirenz in plasma from patients on concurrent HIV/AIDS and tuberculosis treatments.
- 2013
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Ingår i: Biomedical chromatography : BMC. - : Wiley. - 1099-0801 .- 0269-3879. ; 27:11, s. 1554-9
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Tidskriftsartikel (refereegranskat)abstract
- Owing to heterogeneity in therapeutic response, efavirenz is of research and clinical interest. There is a need to quantitate it using noncostly and selective methods. A method for efavirenz quantitation in plasma containing HIV and tuberculosis drugs was developed. Chromatographic separation was carried out using a C18 column. The mobile phase consisted of 0.1% formic acid and acetonitrile, and was pumped at a flow rate of 0.3 mL/min. Efavirenz and ritonavir (internal standard) were monitored at 247 nm. Plasma proteins were precipitated by centrifugation. The analysis time was 6 min. The response was linear (r=0.9997). The accuracy ranged between 98 and 115% (intraday) and between 99 and 117% (interday). The precision ranged from 1.670 to 4.087% (intraday) and from 3.447 to 13.347% (interday). Recovery ranged from 98 to 132%. Stability ranged between 99 and 123%. The selectivity was proven by analysis of drugs used for the management of HIV/AIDS and tuberculosis. Plasma sample analysis showed an efavirenz retention time of 5.57 min and a peak plasma concentration of 2.4 µg/mL occurring at 2 h. This method is rapid and selective, and thus suitable for monitoring efavirenz in patients with HIV/AIDS alone or co-infected with tuberculosis in a less resourced setting.
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| 9. |
- Daryanavard, S. M., et al.
(författare)
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Recent applications of microextraction sample preparation techniques in biological samples analysis
- 2021
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 35:7
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of biological samples is affected by interfering substances with chemical properties similar to those of the target analytes, such as drugs. Biological samples such as whole blood, plasma, serum, urine and saliva must be properly processed for separation, purification, enrichment and chemical modification to meet the requirements of the analytical instruments. This causes the sample preparation stage to be of undeniable importance in the analysis of such samples through methods such as microextraction techniques. The scope of this review will cover a comprehensive summary of available literature data on microextraction techniques playing a key role for analytical purposes, methods of their implementation in common biological samples, and finally, the most recent examples of application of microextraction techniques in preconcentration of analytes from urine, blood and saliva samples. The objectives and merits of each microextration technique are carefully described in detail with respect to the nature of the biological samples. This review presents the most recent and innovative work published on microextraction application in common biological samples, mostly focused on original studies reported from 2017 to date. The main sections of this review comprise an introduction to the microextraction techniques supported by recent application studies involving quantitative and qualitative results and summaries of the most significant, recently published applications of microextracion methods in biological samples. This article considers recent applications of several microextraction techniques in the field of sample preparation for biological samples including urine, blood and saliva, with consideration for extraction techniques, sample preparation and instrumental detection systems.
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| 10. |
- Daryanavard, Seyed, et al.
(författare)
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Molecularly imprinted polymer in microextraction by packed sorbent for the simultaneous determination of local anesthetics : lidocaine, ropivacaine, mepivacaine and bupivacaine in plasma and urine samples
- 2013
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Ingår i: BMC Biomedical chromotography. - : Wiley-Blackwell. - 0269-3879 .- 1099-0801. ; 27:11, s. 1418-1488
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the use of molecularly imprinted polymer (MIP) as packing material for microextraction by packed syringe (MEPS) to achieve higher extraction selectivity. Pentycaine was used as template for MIP. Development and validation of the determination of lidocaine, ropivacaine, mepivacaine and bupivacaine in human plasma and urine samples utilizing MIP-MEPS and liquid chromatography–tandem mass spectrometry (LC-MS/MS) were carried out. The MEPS MIP-cartridge could be used for 100 extractions before it was discarded. The extraction recovery ranged from 60 to 80%. The correlation coefficients values were >0.999 for all assays using lidocaine, ropivacaine, mepivacaine and bupivacaine in the calibration range 5–2000 nmol/L. The accuracy of the studied compounds, given as a percentage variation from the nominal concentration values, ranged from -4.9 to 8.4% using plasma and urine samples. The between-batch precision, given as the relative standard deviation, at three different concentrations (quality control samples) was ranged from −4.7 to 14.0% and from 1.8 to 12.7% in plasma and urine, respectively. The lower limit of quantification and limit of detection of the studied substances were 5.0 and 1.0 nm, respectively
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| 11. |
- Elmongy, Hatem, et al.
(författare)
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Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry
- 2016
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 30:8, s. 1309-1317
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in plasma and saliva samples utilizing liquid chromatography-electrospray ionization tandem mass spectrometry was developed and validated. Human plasma and saliva samples were pretreated by microextraction by packed sorbent (MEPS) prior to analysis. A new MEPS syringe form with two inputs was used. Metoprolol enantiomers and internal standard pentycaine (IS) were eluted from MEPS sorbent using isopropanol after removal of matrix interferences using aliquots of 5% methanol in water. Complete separation of metoprolol enantiomers was achieved on a Cellulose-SB column (150x4.6mm, 5m) using isocratic elution with mobile phase 0.1% ammonium hydroxide in hexane-isopropanol (80:20, v/v) with a flow rate of 0.8mL/min. A post-column solvent-assisted ionization was applied to enhance metoprolol ionization signal in positive mode monitoring (+ES) using 0.5% formic acid in isopropanol at a flow rate of 0.2mL/min. The total chromatographic run time was 10min for each injection. The detection of metoprolol in plasma and saliva samples was performed using triple quadrupole tandem mass spectrometer in +ES under the following mass transitions: m/z 268.0872.09 for metoprolol and m/z 303.3154.3 for IS. The linearity range was 2.5-500ng/mL for both R- and S-metoprolol in plasma and saliva. The limits of detection and quantitation for both enantiomers were 0.5 and 2.5ng/mL respectively, in both matrices (plasma and saliva). The intra- and inter-day precisions were presented in terms of RSD values for replicate analysis of quality control samples and were <5%; the accuracy of determinations varied from 96 to 99%. The method was able to determine the therapeutic levels of metoprolol enantiomers in both human plasma and saliva samples successfully, which can aid in therapeutic drug monitoring in clinical laboratories.
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| 12. |
- Engström, Henrik, et al.
(författare)
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Evaluation of a glucose sensing antibody using weak affinity chromatography
- 2008
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 22:3, s. 272-277
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Tidskriftsartikel (refereegranskat)abstract
- Continuous monitoring of drug levels and endogenous molecules in biological fluids is a developing research area with many applications. One example is the need to improve life for millions of diabetes mellitus patients by continuously monitoring the glucose level. In order to have a dynamic response, the recognition molecule in a continuous sensor should preferentially have a fast dissociation rate and a dissociation constant in the millimolar range. We have evaluated the monoclonal antibody (mAb) 3F1E8-A2 for its potential to be used in a future glucose sensor application. The mAb was generated from hybridomas by immunizing mice with 10 kDa dextran (an α1,6-glucose polymer) with the aim of obtaining mAbs that can recognize the glucose monomer. The mAb was immobilized to macroporous silica and the interaction with dextran-derived oligosaccharides was evaluated with weak affinity chromatography (WAC). To measure the low affinities between the mAb 3F1E8-A2 and different monosaccharides, a competitive weak affinity chromatography approach was employed. It was found that the mAb had a higher specificity for glucose compared with other monosaccharides and the dissociation constant (Kd) towards glucose was determined as 18.8 ± 2.6 mm.
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| 13. |
- Falkenberg, C, et al.
(författare)
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Purification of streptococcal protein G expressed by Escherichia coli by high performance liquid affinity chromatography using immobilized immunoglobulin G and albumin
- 1987
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 2:5, s. 5-221
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Tidskriftsartikel (refereegranskat)abstract
- A one-step HPLC method was developed for the purification of protein G, a cell wall molecule from group C and G streptococci with immunoglobulin G- and albumin-binding properties. Lysed Escherichia coli bacteria infected with lambda-phages containing the protein G gene from group G streptococci were used as a starting material for the preparations. The lysate was applied to a column with immobilized human immunoglobulin G or human serum albumin. Protein G was selectively bound and eluted at pH 2.0. A 750-fold purification was achieved. Sodium dodecylsulfate + polyacrylamide gel electrophoresis showed that the highly purified protein G consisted of three sets of doublets with the apparent molecular weight of 64 and 67, 56 and 58, and 45 and 47 kilodaltons, respectively. A specific method for quantitation of small amounts of protein G was developed and used for specific tracing of the protein after the affinity chromatography. Goat polyclonal antibodies were bound to an antigen coated to the plastic walls of microtiter plates, causing the Fc-region of the immunoglobulins to be directed outwards. Unknown samples of protein G were then allowed to compete with radio-iodinated protein G (solid phase radioassay) or protein G coupled to alkaline phosphatase (enzyme linked sorbent assay) for the Fc-regions.
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| 14. |
- Hellqvist, Alexander, et al.
(författare)
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Development of a capillary electrophoretic method for determination of plasma clearance of iohexol in dogs and cats
- 2015
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Ingår i: BMC Biomedical Chromatography. - : John Wiley & Sons. - 0269-3879 .- 1099-0801. ; 29:4, s. 504-513
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Tidskriftsartikel (refereegranskat)abstract
- Renal function can be monitored by estimation of the glomerular filtration rate (GFR), for example, through measurement of the plasma clearance of a marker that is freely filtrated through the kidney without reabsorption. It has been proposed that iohexol is the most accurate marker for GFR determination in cats and dogs. However, there is a need for a validated capillary electrophoretic method that covers the concentration range for a full curve clearance estimate of iohexol. In the final method, the plasma samples were protein precipitated and the supernatant was analyzed in a background electrolyte containing borate buffer (0.06 m, pH 10.0). The method developed was proved to be linear (concentration range 18- 2900 mg/L) and had a good precision (e.g. 2.3-2.9% at 88 mg/L) and accuracy (e.g. 101-105% at 88 mg/L). Finally, the method was compared with a previously published and validated HPLC-UV method by parallel analysis of clinical plasma samples from dogs and cats administered Omnipaque®. This comparison showed excellent agreement between the two methods and no proportional or systematic error was observed. The proposed method is simple and has a low cost per sample, which makes it applicable for routine analysis.
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| 15. |
- Huang, Juan, et al.
(författare)
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Differential metabolic profiles of ginsenosides in artificial gastric juice using ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry
- 2022
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Ingår i: BMC Biomedical chromotography. - : John Wiley & Sons. - 0269-3879 .- 1099-0801. ; 36:12
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Tidskriftsartikel (refereegranskat)abstract
- Ginsenosides have poor oral bioavailability and undergo rapid biological transformation in the complex gastrointestinal environment. Most studies on the metabolism of ginsenosides have focused on gut bacteria, yet gastric juice remains a nonnegligible factor. Metabolic profiles of ginsenoside monomers formed in artificial gastric juice were separately investigated and qualitatively identified using ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MSn). A common pattern of their metabolic pathways was established, showing that ginsenosides were transformed via deglycosylation, hydration, and dehydration pathways. Two major structure types, 20(S), 20(R)-protopanaxatriols and 20(S), 20(R)-protopanaxadiols, basically shared similar transformation pathways and yielded deglycosylated, hydrated, and dehydrated products. Fragmentation patterns of major ginsenosides were also discussed. Consequently, gastric juice, as the primary link in ginsenoside metabolism and as important as the intestinal flora, produces considerable amounts of degraded ginsenosides, providing a partial explanation for the low bioavailabilities of primary ginsenosides.
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| 16. |
- Jansson Löfmark, Rasmus, 1979, et al.
(författare)
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Determination of eflornithine enantiomers in plasma by precolumn derivatization with o-phthalaldehyde-N-acetyl-l-cysteine and liquid chromatography with UV detection
- 2010
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 24:7, s. 768-773
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Tidskriftsartikel (refereegranskat)abstract
- A bioanalytical method for indirect determination of eflornithine enantiomers in 75 mu L human plasma has been developed and validated. L- and D-eflornithine were derivatized with o-phthalaldehyde and N-acetyl-L-cysteine to generate diastereomers which were separated on two serially connected Chromolith Performance columns (RP-18e 100 x 4.6 mm i.d.) by a isocratic flow followed by a gradient flow for elution of endogenous compounds. The diastereomers were detected with UV (340 nm). The between-day precisions for L- and D-eflornithine in plasma were 8.4 and 2.3% at 3 mu m, 4.0 and 5.1% at 400 mu m, and 2.0 and 3.7% at 1000 mu m. The lower limit of quantification was determined to be 1.5 mu m, at which precision was 14.9 and 9.9% for 1- and D-eflornithine, respectively.
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| 17. |
- Johannesson, Gunvor, et al.
(författare)
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Evaluation of an immunoaffinity extraction column for enrichment of adducts between human serum albumin and hexahydrophthalic anhydride in plasma.
- 2008
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 22:3, s. 327-332
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Tidskriftsartikel (refereegranskat)abstract
- An immunoaffinity extraction (IAE) column was prepared for extraction of adducts between human serum albumin (HSA) and hexahydrophthalic anhydride (HHPA). HHPA is a strong sensitizer inducing immunoglobulin E antibodies in vivo. Polyclonal antibodies from a rabbit immunized with keyhole limpet hemocyananin-HHPA conjugate were purified using a Protein A Sepharose gel. To obtain antibodies with optimal affinity towards HHPA-protein adducts, HHPA-specific antibodies were selected using an N-hydroxysuccinimide-Sepharose column coupled with albumin-HHPA conjugate. Antibodies eluted from this column at pH 2.2 were selected to prepare the IAE column. The column was evaluated using 2 mL plasma spiked with HSA-HHPA conjugate. The column was eluted with glycine buffer at pH 2.0. The conjugates in the eluate were hydrolyzed to the corresponding HHP acid and quantified by mass spectrometry. The average recovery of HHPA adducts in 11 experiments was 68% with a coefficient of variation (CV) of 7%. The column's capacity to bind protein-HHPA adducts was found to be linear in the range of 0.15-1.2 nmol conjugate. The evaluation showed that the IAE column had adequate affinity towards the HHPA adducts and that the adducts could be extracted with good recovery and precision from a large volume of plasma.
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| 18. |
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| 19. |
- Karlsson, Krister, et al.
(författare)
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Chromatographic characterization of substance P endopeptidase in the rat brain reveals affected enzyme activity following heat stress
- 2006
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 20:1, s. 77-82
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a study of substance P endopeptidase (SPE)-like activity in various regions of the brain from male rats subjected to heat stress (HS). The enzyme activity was found to be affected in several brain areas including cerebellum, cerebral cortex, hippocampus, hypothalamus[sol ]thalamus and the spinal cord following HS. Significant increases in SPE activity were observed in, for example, hippocampus and the spinal cord. SPE-containing extracts from hippocampus were pooled and subsequently purified by size exclusion chromatography (using a Superdex® 75 HR column) and by anion-exchange chromatography (using Resource Q® column). The gel permeation chromatography separated the SPE-like activity into two fractions, one of which was suggested to be identical to neutral endopeptidase owing to its molecular size and inhibitory profile. The other active enzyme fraction behaved in conformity with SPE, previously identified in human cerebrospinal fluid. The activity of the purified fraction of these two enzymes was found to be increased (27%) in HS-treated animals.
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| 20. |
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| 21. |
- Lundquist, Anna, et al.
(författare)
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Interactions of drugs and an oligonucleotide with charged membranes analyzed by immobilized liposome chromatography
- 2006
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 20, s. 83-87
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Tidskriftsartikel (refereegranskat)abstract
- We studied the effect of charged lipids or detergent on the retention of drugs and an oligonucleotide by immobilized liposome chromatography to characterize solute-membrane interactions. This is a novel approach in analysis of oligonucleotide-liposome interactions. The charged lipids (phosphatidylserine or distearoyltrimethylammoniumpropane) or detergent (sodium dodecylsulfate) interacted electrostatically in a concentration-dependent matter with the solutes. The oligonucleotide ions presumably bound to the liposomes by multipoint interactions, which was saturable. Sodium dodecylsulfate seemed to affect the drug-membrane interactions more strongly than phosphatidylserine did, probably due to different positioning in the bilayer.
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| 22. |
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| 23. |
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| 24. |
- Odin, Elisabeth, 1955, et al.
(författare)
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Determination of reduced folates in tumor and adjacent mucosa of colorectal cancer patients using LC-MS/MS.
- 2013
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Ingår i: Biomedical chromatography : BMC. - : Wiley. - 1099-0801 .- 0269-3879. ; 27:4, s. 487-495
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Tidskriftsartikel (refereegranskat)abstract
- A liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) method has been developed for the determination of 5,10-methylenetetrahydrofolate (methyleneTHF), tetrahydrofolate (THF) and 5-methyltetrahydrofolate (methylTHF) in colorectal mucosa and tumor tissues. The folate extraction method includes homogenization, heat and folate conjugase treatment to hydrolyze polyglutamyl folate to monoglutamyl folate. Before analysis on LC-MS/MS, simple and fast sample purification with ultrafiltration (molecular weight cut-off membrane, 10kDa) was performed. Folates were detected and quantified using positive electrospray. The method described in the present paper was successfully applied to determine the level of three folate monoglutamates in mucosa and tumor samples from 77 colorectal cancer patients, starting from a limited amount of tissue. The results showed that the LC-MS/MS method has a great advantage over other previously used methods because of its high sensitivity and selectivity. Significantly higher levels of methyleneTHF and THF were found in tumor compared with matched mucosa tissues. Folate levels in adjacent mucosa were associated with tumor location, age and gender. The correlation between folate levels and tumor site further strengthens the fact that development of right- and left-sided tumors follows different pathways. Copyright © 2012 John Wiley & Sons, Ltd.
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| 25. |
- Pereira, Jorge, et al.
(författare)
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Microextraction by packed sorbent : an emerging, selective and high-throughput extraction technique in bioanalysis
- 2014
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 28:6, s. 839-847
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Tidskriftsartikel (refereegranskat)abstract
- Sample preparation is an important analytical step regarding the isolation and concentration of desired components from complex matrices and greatly influences their reliable and accurate analysis and data quality. It is the most labor-intensive and error-prone process in analytical methodology and, therefore, may influence the analytical performance of the target analytes quantification. Many conventional sample preparation methods are relatively complicated, involving time-consuming procedures and requiring large volumes of organic solvents. Recent trends in sample preparation include miniaturization, automation, high-throughput performance, on-line coupling with analytical instruments and low-cost operation through extremely low volume or no solvent consumption. Micro-extraction techniques, such as micro-extraction by packed sorbent (MEPS), have these advantages over the traditional techniques. This paper gives an overview of MEPS technique, including the role of sample preparation in bioanalysis, the MEPS description namely MEPS formats (on- and off-line), sorbents, experimental and protocols, factors that affect the MEPS performance, and the major advantages and limitations of MEPS compared with other sample preparation techniques. We also summarize MEPS recent applications in bioanalysis.
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| 26. |
- Roseboom, Ignace C, et al.
(författare)
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Bioanalytical methods for pharmacokinetic studies of antileishmanial drugs
- 2023
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Ingår i: BMC Biomedical chromotography. - : John Wiley & Sons. - 0269-3879 .- 1099-0801. ; 37:7
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Tidskriftsartikel (refereegranskat)abstract
- Bioanalytical method development and validation for the quantification of antileishmanial drugs are pivotal to support clinical trials and provide the data necessary to conduct pharmacokinetic (PK) analysis. This review provides a comprehensive overview of published validated bioanalytical assays for the quantification of antileishmanial drugs amphotericin B, miltefosine, paromomycin, pentamidine, and pentavalent antimonials in human matrices. The applicability of the assays for leishmaniasis clinical trials as well as their relevance to PK studies with emphasis on the choice of matrix, calibration range, sample volume, sample preparation, choice of internal standards, separation, and detection was discussed for each antileishmanial drug. Given that no published bioanalytical methods included multiple antileishmanial drugs in a single assay although antileishmanial shortened combination regimens currently were under investigation, it was recommended to combine various drugs in a single bioanalytical method. Furthermore, bioanalytical method development regarding target site matrix as well as applying microsampling strategies was recommended to optimize future clinical PK studies in leishmaniasis.
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| 27. |
- Schmidtchen, Artur, et al.
(författare)
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Hydrophobic interaction chromatography of fibroblast proteoglycans
- 1993
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 7:1, s. 48-55
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Forskningsöversikt (refereegranskat)abstract
- We have investigated the hydrophobic properties of human skin fibroblast proteoglycans and related material by affinity chromatography on Octyl-Sepharose CL-4B in 4 M guanidinium hydrochloride (GdnHCl). Proteoglycans and related material could be separated into non-, medium and highly hydrophobic forms by elution with gradients of Triton X-100 in 4 M Gdn HCl. The non-hydrophobic material included endogenously produced glycosaminoglycan chains and oligosaccharides as well as an HS-proteoglycan with a 35 kDa core. The 65-70 kDa core (glypican-related) proteoglycans appeared among the highly hydrophobic ones, but variable proportions were seen both in the medium and the non-hydrophobic material. Other membrane-bound proteoglycans, like fibroglycan (45 kDa core) and the HS-proteoglycans with 90 and 130 kDa cores, as well as the CS/DS-proteoglycan with a 90 kDa core, were all of high hydrophobicity. There were also indications of a highly hydrophobic CS/DS-proteoglycan with a 45 kDa core. The extracellular proteoglycans, PG-L, PG-S1 and PG-S2, and the HS-proteoglycans with 350 and 250 kDa cores were all of medium hydrophobicity. These proteoglycans emerged in distinct positions when the column was eluted with a gradient of 3-[(3-cholamidopropyl)dimethylammonio]propanesulphonate.
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| 28. |
- Skoglund, Christina, et al.
(författare)
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Monolithic packed 96-tips set for high-throughput sample preparation : determination of cyclophosphamide and busulfan in whole blood samples by monolithic packed 96-tips and LC-MS
- 2013
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 27:6, s. 714-719
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Tidskriftsartikel (refereegranskat)abstract
- A monolithic methacrylate packed 96-tips device was used for the extraction of the busulfan and cyclophosphamide in whole blood samples. Using a packed 96-tips set, a 96-well plate could be handled in about 2min. The key aspect of the monolithic phase is that monolithic material can offer both good extraction capacity and low-back-pressure properties. The validation of the methodology showed that the accuracy values of quality-control samples were between 99 and 113% for busulfan, and between 103 and 110% for cyclophosphamide. The inter-day precision ranged from 7.0 to 12% for busulfan and from 13 to 16% for cyclophosphamide. The standard calibration curves were obtained within the concentration range 52000nm for busulfan and from 10 to 5000nm for cyclophosphamide in blood samples. The coefficients of determination were 0.99.
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| 29. |
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| 30. |
- Vikingsson, Svante, et al.
(författare)
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Novel rapid liquid chromatography tandem masspectrometry method for vemurafenib and metabolites in human plasma, including metabolite concentrations at steady-state.
- 2016
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Ingår i: BMC Biomedical chromotography. - : John Wiley & Sons. - 0269-3879 .- 1099-0801. ; 30:8, s. 1234-1239
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Tidskriftsartikel (refereegranskat)abstract
- A novel, rapid and sensitive liquid chromatography tandem-mass spectrometry method for quantification of vemurafenib in human plasma, that also for the first time allows for metabolite semi-quantification, was developed and validated to support clinical trials and therapeutic drug monitoring. Vemurafenib was analysed by precipitation with methanol followed by a 1.9 min isocratic liquid chromatography tandem masspectrometry analysis using an Acquity BEH C18 column with methanol and formic acid using isotope labelled internal standards. Analytes were detected in multi reaction monitoring mode on a Xevo TQ. Semi-quantification of vemurafenib metabolites was performed using the same analytical system and sample preparation with gradient elution. The vemurafenib method was successfully validated in the range 0.5-100 µg/mL according to international guidelines. The metabolite method was partially validated due to the lack of commercially available reference materials. For the first time concentration levels at steady-state for melanoma patients treated with vemurafenib is presented. The low abundance of vemurafenib metabolites suggests that they lack clinical significance. This article is protected by copyright. All rights reserved.
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| 31. |
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| 32. |
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| 33. |
- Zhao, Guohua, et al.
(författare)
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Rapid determination of short-chain fatty acids in colonic contents and faeces of humans and rats by acidified water-extraction and direct-injection gas chromatography
- 2006
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 20:8, s. 674-682
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Tidskriftsartikel (refereegranskat)abstract
- Short-chain fatty acids (SCFAs) have attracted much attention recently because of their positive physiological effects. In this work, a rapid and reliable gas chromatographic method for determination of eight SCFAs, in colonic and faecal samples from rats and humans has been developed and validated. The methodology involves extraction of the SCFAs in water before a direct injection procedure on a FFAP capillary column. A stock standard solution containing acetic acid, propionic acid, n-butyric acid, i-butyric acid, n-valeric acid, i-valeric acid, n-caproic acid and n-heptanoic acid was prepared and used. A high linearity (r(2) > 0.9990), low quantification limit (2.38-30.14 mu M) and high recovery for most acids were obtained. Acidification of faecal samples was found to be crucial for quantitative determination of the SCFAs, and adjustment of pH to 2-3 was regarded as necessary. Glass wool inserted in the glass liner of the injection port proved effective in preventing the contamination of the column by non-volatiles, and 12% formic acid reduced the ghost peak that appeared gradually after several injections. After validation, the methodology was applied on two faecal samples from rats fed diets containing different amount of dietary fibre and one faecal sample from human fed a normal diet to test the accuracy of the developed method. Copyright (c) 2005 John Wiley & Sons, Ltd.
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| 34. |
- Zohdijamil, Zeynab, et al.
(författare)
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Functionalized graphene oxide tablets for sample preparation of drugs in biological fluids : Extraction of ritonavir, a HIV protease inhibitor, from human saliva and plasma using LC–MS/MS
- 2021
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Ingår i: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 35:12
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Tidskriftsartikel (refereegranskat)abstract
- In this work, graphene oxide–based tablets (GO-Tabs) were prepared by applying a thin layer of functionalized GO on a polyethylene substrate. The GO was functionalized with amine groups (–NH2) by poly(ethylene glycol)bis(3-aminopropyl) terminated (GO-NH2-PEG-NH2). The functionalized GO-Tabs were used for the extraction of ritonavir (RTV) in human saliva samples. RTV in plasma and saliva samples was analyzed using LC–MS/MS. Gradient LC system with MS/MS in the positive-ion mode [electrospray ionization (ESI+)] was used. The transitions m/z 721 → 269.0 and m/z 614 → 421 were used for RTV and the internal standard indinavir, respectively. This study determined the human immunodeficiency virus protease inhibitor RTV in human saliva samples using functionalized GO-Tab and LC–MS/MS, and the method was validated. The standard calibration curve for plasma and saliva samples was constructed from 5.0 to 2000 nmol L−1. The limit of detection was 0.1 nmol L−1, and the limit of quantification was 5.0 nmol L−1 in both plasma and saliva matrices. The intra- and inter-assay precision values were found to be between 1.5 and 5.8%, and the accuracy values ranged from 88.0 to 108% utilizing saliva and plasma samples. The extraction recovery was more than 80%, and the presented functionalized GO-Tabs could be reused for more than 10 extractions without deterioration in recovery.
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| 35. |
- Ärlemalm, Andreas, et al.
(författare)
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Rapid determination of acyclovir, its main metabolite 9-carboxymethoxymethylguanine, ganciclovir, and penciclovir in human serum using LC-MS/MS
- 2022
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Ingår i: BMC Biomedical chromotography. - Oxford, United Kingdom : John Wiley & Sons. - 0269-3879 .- 1099-0801. ; 36:4
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Tidskriftsartikel (refereegranskat)abstract
- A novel MS-based analytical method for simultaneous analysis of the antiviral drugs acyclovir, its metabolite 9-carboxymethoxymethylguanine, ganciclovir, and penciclovir in human serum is described. These antiviral drugs are active against herpes virus infections. Acyclovir and penciclovir are regarded as safe and effective medicines with mild side effects such as headache and gastrointestinal discomfort, and ganciclovir is regarded as more toxic and is known to cause, for example, bone marrow suppression. Acyclovirs main metabolite 9-carboxymethoxymethylguanine is a presumptive neurotoxin and should be monitored in patients with impaired renal function or in cases with neurotoxic symptoms. A sample was prepared using protein precipitation with 1% formic acid in methanol containing isotopically labeled internal standard. Chromatographic separation on a biphenyl column and mass spectrometric detection were performed in multiple reaction monitoring (MRM) mode on a Xevo TQ-S micro with ESI in positive ion mode, within 3 min. Inter-day assay accuracies for the quality controls varied between 95 and 104% and intra-day assay between 93 and 105%. Inter-day and intra-day assay imprecision for the quality controls ranged between 1.4 and 4.2% and 1.7 and 6.5% respectively. The lower limit of quantification for all four substances was 0.156 mu mol/L. It is an accurate and reproducible method for therapeutic drug monitoring.
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| 36. |
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| 37. |
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