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Amini, Ahmad
Publications (10 of 14) Show all publications
Amini, A. (2016). Analysis of somatropin by double-injection capillary-zone electrophoresis in polybrene/chondroitin sulfate a double-coated capillaries. In: Nguyet Thuy Tran, Myriam Taverna (Ed.), Capillary Electrophoresis of Proteins and Peptides: Methods and Protocols (pp. 93-105). New York: Springer-Verlag New York
Open this publication in new window or tab >>Analysis of somatropin by double-injection capillary-zone electrophoresis in polybrene/chondroitin sulfate a double-coated capillaries
2016 (English)In: Capillary Electrophoresis of Proteins and Peptides: Methods and Protocols / [ed] Nguyet Thuy Tran, Myriam Taverna, New York: Springer-Verlag New York, 2016, p. 93-105Chapter in book (Refereed)
Abstract [en]

Purity determination of somatropin as a recombinant protein is important to ensure its safety and quality. This is carried out by capillary zone electrophoresis in double-injection mode using polybrene/chondroitin sulfate A double-coated capillaries. Modification of the capillary wall eliminates protein-wall interactions which results in improved accuracy and precision of the determinations. In the double-injection mode two somatropin samples are analyzed within a single electrophoretic run. Prior to the second injection, the first injected plug is electrophoresed for a predetermined time period in order to adjust the inter- plug distance. Here, the principle for the separation of somatropin charge variants is described.

Place, publisher, year, edition, pages
New York: Springer-Verlag New York, 2016
Series
Methods in Molecular Biology, ISSN 1064-3745 ; 1466
Keywords
Double-injection capillary-zone electrophoresis (DICZE), Partial electrophoresis time period (tPE), Polybrene/ chondroitin sulfate A (PB/CA) double-coated capillary, Somatropin
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-310283 (URN)10.1007/978-1-4939-4014-1_8 (DOI)2-s2.0-84990242861 (Scopus ID)978-1-4939-4012-7 (ISBN)978-1-4939-4014-1 (ISBN)
Available from: 2016-12-15 Created: 2016-12-13 Last updated: 2018-01-13Bibliographically approved
Elmongy, H., Ahmed, H., Wahbi, A.-A., Amini, A., Colmsjö, A. & Abdel-Rehim, M. (2016). Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry. BMC Biomedical chromotography, 30(8), 1309-1317
Open this publication in new window or tab >>Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry
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2016 (English)In: BMC Biomedical chromotography, ISSN 0269-3879, E-ISSN 1099-0801, Vol. 30, no 8, p. 1309-1317Article in journal (Refereed) Published
Abstract [en]

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 (150 × 4.6 mm, 5 μm) using isocratic elution with mobile phase 0.1% ammonium hydroxide in hexane-isopropanol (80:20, v/v) with a flow rate of 0.8 mL/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 0.2 mL/min. The total chromatographic run time was 10 min 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 268.08 → 72.09 for metoprolol and m/z 303.3 → 154.3 for IS. The linearity range was 2.5-500 ng/mL for both R- and S-metoprolol in plasma and saliva. The limits of detection and quantitation for both enantiomers were 0.5 and 2.5 ng/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.

National Category
Pharmaceutical Sciences Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-309926 (URN)10.1002/bmc.3685 (DOI)26766521 (PubMedID)
Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2018-01-13Bibliographically approved
Durgaryan, A., Rundlöf, T., Lavén, M. & Amini, A. (2016). Identification of human chorionic gonadotropin hormone in illegally distributed products by MALDI-TOF mass spectrometry and double-injection capillary zone electrophoresis. Analytical Methods, 8(21), 4188-4196
Open this publication in new window or tab >>Identification of human chorionic gonadotropin hormone in illegally distributed products by MALDI-TOF mass spectrometry and double-injection capillary zone electrophoresis
2016 (English)In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 8, no 21, p. 4188-4196Article in journal (Refereed) Published
Abstract [en]

This paper describes two complementary methods, based on peptide-mass fingerprinting (PMF) using MALDI-TOF mass spectrometry and double injection capillary zone electrophoresis for identification of human chorionic gonadotropin (hCG). The identification was performed by determining the amino acid composition and comparing measured mass spectra with those predicted in silico. Capillary zone electrophoresis in double injection mode (DICZE) was used to confirm the identity of the protein. In DICZE, the identification was performed by analyzing illegal samples together with the corresponding reference standard during a double injection capillary zone electrophoretic run. The identification was based on the closeness of agreement between the calculated migration time (t(mig(c))) and the observed migration time (tmig) of the reference standard. Furthermore, the DICZE method provides the possibility to compare the electrophoretic separation patterns of the native reference standard and the target analyte. The inner surface of the capillary was dynamically coated with putrescine, present in the BGE at 8.2 mM, to improve the separation. The CZE analyses revealed that the protein consisted of at least ten glycosylated isoforms.

National Category
Analytical Chemistry Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-296402 (URN)10.1039/c6ay01078d (DOI)000377511800004 ()
Available from: 2016-06-16 Created: 2016-06-16 Last updated: 2018-01-10Bibliographically approved
Amini, A., Rundlöf, T., Rönnquist, K., Tydén, M., Turunen, T., Korhola, P. & Anette, P. (2015). A protocol for the quality assessment of illegally distributed human growth hormones with respect to identity, purity, endotoxin level and microorganism content. Analytical Methods, 7(20), 8857-8864
Open this publication in new window or tab >>A protocol for the quality assessment of illegally distributed human growth hormones with respect to identity, purity, endotoxin level and microorganism content
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2015 (English)In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 7, no 20, p. 8857-8864Article in journal (Refereed) Published
Abstract [en]

Different methods based on MALDI-TOF-MS and double injection capillary zone electrophoresis (DICZE) were used for the identification and purity determination of somatropin in illegally distributed products. During the past few years, more than 200 products suspected to contain somatropin have been analysed. Some of the samples were also subjected to control microorganisms and endotoxins. The identification of somatropin was carried out by peptide mapping using trypsin as the proteolytic enzyme. A double chain peptide cross-linked via a disulfide bond was used as the signature peptide. Capillary electrophoresis in double injection mode was applied to both identification and purity determination of the samples. The identification was based on the comparison between the observed migration time of the reference standard and the calculated migration time of the analyte, being present in the second injection plug. The DICZE provides electrophoretic fingerprints of intact somatropin and the related proteins which facilitate the identification. In addition, some of these samples revealed the presence of microorganisms as well as a high level of endotoxins. Taken together, the doubtful quality of the analysed samples and the microbiological findings represent a serious threat for the consumers and public health.

National Category
Pharmaceutical Sciences Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-264542 (URN)10.1039/C5AY01390A (DOI)000362662600049 ()
Available from: 2015-10-14 Created: 2015-10-14 Last updated: 2018-01-11Bibliographically approved
Abuzooda, T., Amini, A. & Abdel-Rehim, M. (2015). Graphite-based microextraction by packed sorbent for online extraction of β-blockers from human plasma samples. Journal of chromatography. B, 992, 86-90
Open this publication in new window or tab >>Graphite-based microextraction by packed sorbent for online extraction of β-blockers from human plasma samples
2015 (English)In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 992, p. 86-90Article in journal (Refereed) Published
Abstract [en]

In the present work a new graphitic material (Carbon-XCOS) was used as a sorbent for microextraction by packed sorbent (MEPS). The β-blockers metoprolol and acebutolol in plasma samples were extracted and detected online using Carbon-MEPS syringe and liquid chromatography and tandem mass spectrometry (LC-MS/MS). Factors affecting the MEPS performance such as conditioning, washing and elution solutions were investigated. The validation of the bioanalytical method was performed using human plasma. The standard curve ranged from 10 to 2000nM and the lower limit of quantification (LLOQ) was set to 10nM. The method validation showed good accuracy and precision for the quality control (QC) samples at three concentration levels (30, 800 and 1600nM). The accuracy values of the QC samples were in the range of 86-108% (n=18). The precision values of intra- and inter-day for QC samples ranged from 4.4% to 14.4% (RSD) for the both studied analytes. The coefficient of determination (R(2)) values were ≥0.999 (n=3).

National Category
Pharmaceutical Sciences Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-271344 (URN)10.1016/j.jchromb.2015.04.027 (DOI)25958323 (PubMedID)
Available from: 2016-01-07 Created: 2016-01-07 Last updated: 2018-01-10Bibliographically approved
Amini, A. (2015). Identification of Ɛ-Caprolactam and Melamine in Polyvinyl- Pyrrolidone Powder by Double Injection Micellar Elektrokinetic Chromatography. Pharmaceutica analytica acta, 6(11), Article ID 1000442.
Open this publication in new window or tab >>Identification of Ɛ-Caprolactam and Melamine in Polyvinyl- Pyrrolidone Powder by Double Injection Micellar Elektrokinetic Chromatography
2015 (English)In: Pharmaceutica analytica acta, ISSN 2153-2435, Vol. 6, no 11, article id 1000442Article in journal (Refereed) Published
Abstract [en]

A double-injection micellar electrokinetic chromatography (DIMEKC) method for the identification of Ɛ- caprolactam andmelamine deliberately added to povidone (polyvinylpyrrolidone) products has been developed. The separations were performedin 89 mM phosphate buffer (pH 7.4) containing 52 mM sodium dodecyl sulfate (SDS) in fused silica capillaries with UV absorptiondetection at 200 nm. The identification relied on the agreement between the calculated migration time (t mig(c) ) of the analytes andthe migration time (t mig ) of their corresponding reference standards being analysed simultaneously within a double injection run.The migration time of the analytes was calculated from the partial migration times (t mig(p) ) as described in this paper. The migrationtime ratios (t mig(c) / t mig ) varied

National Category
Pharmaceutical Sciences Analytical Chemistry
Research subject
Analytical Pharmaceutical Chemistry
Identifiers
urn:nbn:se:uu:diva-292978 (URN)10.4172/2153-2435.1000442 (DOI)
Available from: 2016-05-11 Created: 2016-05-11 Last updated: 2018-01-10Bibliographically approved
Amini, A. (2014). Double-injection capillary electrophoresis for the identification of analytes. Electrophoresis, 35(20), 2915-2921
Open this publication in new window or tab >>Double-injection capillary electrophoresis for the identification of analytes
2014 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 35, no 20, p. 2915-2921Article in journal (Refereed) Published
Abstract [en]

This paper presents a new approach for identifying analytes by CE. The compound to be identified is analyzed together with the corresponding reference standard during a double injection capillary electrophoretic run. The inter-plug distance is regulated by applying an electrical field over the capillary for a predetermined time period (tPE). The migration time of an analyte being exposed to the partial electrophoresis was calculated from the partial migration time (tmig(p)) as described in this paper. The identification is based on the closeness of agreement between the calculated migration time (tmig(c)) and observed migration time (tmig) of the reference standard. The validity of the derived equations was checked by analyzing several substances such as caffeine, melamine, acetyl salicylic acid, paracetamol, ibuprofen, metoprolol, naproxen, somatropin, several insulin analogs, as well as different pharmaceutical and natural products. The migration time ratios for the identified solutes varied between 0.996 and 1.006 (i.e., 1.001 ± 0.005), indicating good agreement between the observed and calculated migration times.

National Category
Pharmaceutical Sciences Analytical Chemistry
Research subject
Analytical Pharmaceutical Chemistry
Identifiers
urn:nbn:se:uu:diva-236508 (URN)10.1002/elps.201400229 (DOI)000343833000003 ()
Available from: 2014-11-19 Created: 2014-11-19 Last updated: 2018-01-11Bibliographically approved
Amini, A. (2014). Identification of ε-caprolactam, melamine and urea in polyvinylpyrrolidone powders by micellar electrokinetic chromatography. Journal of Pharmaceutical and Biomedical Analysis, 91, 12-16
Open this publication in new window or tab >>Identification of ε-caprolactam, melamine and urea in polyvinylpyrrolidone powders by micellar electrokinetic chromatography
2014 (English)In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 91, p. 12-16Article in journal (Refereed) Published
Abstract [en]

A sodium dodecyl sulfate micellar electrokinetic chromatography (SDS-MEKC) method for the simultaneous separation and identification of ɛ-caprolactam, melamine and urea deliberately added to polyvinylpyrrolidone (povidone) products has been developed. All samples to be analyzed contained paracetamol as an internal marker (IM). The optimized separations were performed in 50 mM phosphate buffer (pH 7.0) containing 2% (w/v) sodium dodecyl sulfate (SDS) in fused silica capillaries with UV absorption detection at 200 nm. The method was validated with respect to repeatability and intermediate precision, selectivity and robustness with satisfactory results. The relative migration times (RMT) were found to be between 0.03% and 0.13% for intra-day precision and between 0.50% and 0.60% for inter-day precision in four days. The detection limits were determined to be 1.3 (11.5 μM), 0.4 (3.5 μM) and 41 μg/ml (0.4 mM) for ɛ-caprolactam, melamine and urea, respectively.

National Category
Pharmaceutical Sciences Analytical Chemistry
Research subject
Analytical Pharmaceutical Chemistry
Identifiers
urn:nbn:se:uu:diva-215114 (URN)10.1016/j.jpba.2013.12.010 (DOI)000332348700003 ()
Available from: 2014-01-10 Created: 2014-01-10 Last updated: 2018-01-11Bibliographically approved
Amini, A. (2013). Separation of somatropin charge variants by multiple-injection CZE with Polybrene/chondroitin sulfate A double-coated capillaries. Journal of Separation Science, 36(16), 2686-2690
Open this publication in new window or tab >>Separation of somatropin charge variants by multiple-injection CZE with Polybrene/chondroitin sulfate A double-coated capillaries
2013 (English)In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 36, no 16, p. 2686-2690Article in journal (Refereed) Published
Abstract [en]

The performance of dynamic double-coated fused-silica capillaries with Polybrene and chondroitin sulfate A has been compared with uncoated fused-silica capillaries for the determination of recombinant human growth factor (somatropin) charge variants. The separations were carried out under the same electrophoretic conditions as described in the European Pharmacopoeia, i.e. at pH 6.0 and 30 degrees C. The coating significantly reduced the interactions between the proteins and the surface of the fused-silica capillary. The first five separations performed in a new bare fused-silica capillary were discarded because of very poor separation performance as a result of protein-surface interactions. There was an approximate twofold increase in the interday migration time precision (%RSD 6.5%) in the double-coated capillaries. The method was successfully transferred to a multiple CZE mode where two samples were analyzed in a single electrophoretic run. The average purity of somatropin certified reference standard was 98.0% (%RSD 0.3%) determined by using uncoated and coated capillaries.

Keywords
CZE, Double-coated capillaries, European Pharmacopoeia, Somatropin charge variants, Somatropin CRS
National Category
Natural Sciences Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-206993 (URN)10.1002/jssc.201300327 (DOI)000322994600017 ()
Available from: 2013-09-09 Created: 2013-09-09 Last updated: 2017-12-06Bibliographically approved
Amini, A., Lodén, H., Pettersson, C. & Arvidsson, T. (2008). Principles for different modes of multiple-injection CZE. Electrophoresis, 29(19), 3952-3958
Open this publication in new window or tab >>Principles for different modes of multiple-injection CZE
2008 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 29, no 19, p. 3952-3958Article in journal (Refereed) Published
Abstract [en]

This paper introduces four different modes of multiple-injection CZE (MICZE). The validity of these MICZE models was evaluated by the experimental data. Prior to the application of MICZE, the electrophoretic conditions are developed in the single-injection mode by adjusting different experimental parameters such as pH, type and concentration of buffer additives and temperature. Based on the migration time difference (tmig) between the analyte and the internal standard or injection marker, one or more MICZE modes can be employed. The injection marker is added to the sample to compensate for injection-volume fluctuations. The inter-plug distance is regulated by applying an electrical field over the capillary for a short period of time between each injection. After the final injection, the separation is completed by electrophoresis for a time period corresponding to that in the single-injection mode

Place, publisher, year, edition, pages
Wiley, 2008
Keywords
Moxonidine, Multiple-injection, Oxprenolol, Phenylpropanolamine, Salbutamol
National Category
Medicinal Chemistry
Research subject
Analytical Pharmaceutical Chemistry
Identifiers
urn:nbn:se:uu:diva-86740 (URN)10.1002/elps.200800398 (DOI)000261049400002 ()
Note
Conference Information: 7th Asia-Pacific International Symposium on Microscale Separations and Analysis Singapore, SINGAPORE, DEC 17-19, 2007 Available from: 2008-12-01 Created: 2008-12-01 Last updated: 2018-01-13Bibliographically approved
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