Alina Plenis - Academia.edu (original) (raw)

Papers by Alina Plenis

Molecules

A new approach for the sensitive, robust and rapid determination of idarubicin (IDA) in human pla... more A new approach for the sensitive, robust and rapid determination of idarubicin (IDA) in human plasma and urine samples based on liquid chromatography with fluorescence detection (LC-FL) was developed. Satisfactory chromatographic separation of the analyte after solid-phase extraction (SPE) was performed on a Discovery HS C18 analytical column using a mixture of acetonitrile and 0.1% formic acid in water as the mobile phase in isocratic mode. IDA and daunorubicin hydrochloride used as an internal standard (I.S.) were monitored at the excitation and emission wavelengths of 487 and 547 nm, respectively. The method was validated according to the FDA and ICH guidelines. The linearity was confirmed in the range of 0.1–50 ng/mL and 0.25–200 ng/mL, while the limit of detection (LOD) was 0.05 and 0.125 ng/mL in plasma and urine samples, respectively. The developed LC-FL method was successfully applied for drug determinations in human plasma and urine after oral administration of IDA at a dos...

Molecular Medicine Reports, 2014

Neuroendocrine tumors (NET) often develop asymptomatically and are detected at a late stage. Curr... more Neuroendocrine tumors (NET) often develop asymptomatically and are detected at a late stage. Currently, there exist certain markers of NET that occur only in the advanced stages of the disease. Still, there is need to develop markers specific of the early stage of cancer development. Nevertheless, biomarkers are mostly low‑abundant proteins and require separation from complex protein mixtures, which remains a major challenge. The goal of the present study was to optimize one‑dimensional‑polyacrylamide gel electrophoresis (1D‑PAGE) for separation and comparison of protein composition from neuroendocrine tumor samples. 1D‑PAGE was optimized by modification of the gel concentration and by comparison of different gel staining protocols. In addition, several steps prior to electrophoresis were carried out to purify and preliminarily reduce the complexity of the sample. The results of these optimization steps indicated that use of an albumin removal kit can considerably decrease the amount of albumin in the samples, thereby allowing to detect proteins of low abundance. Optimal separation of the sample was obtained using a 12% polyacrylamide gel. Furthermore, the use of silver staining allowed detection of proteins at nanogram levels, whereas for Coomassie Brilliant Blue staining, the detection limit was 10 times higher. Optimization of the sample preparation workflow and parameters of the electrophoretic separation allowed to reduce the complexity of the studied material and facilitated further identification of proteins of low abundance in the sample. This study demonstrated that analysis of the secreted proteome of NET cells by 1D‑PAGE is a simple and suitable tool for the identification of potential NET protein biomarkers.

Journal of Liquid Chromatography & Related Technologies, 2010

A rapid high-performance liquid chromatographic method with UV detection (HPLC-UV) for the simult... more A rapid high-performance liquid chromatographic method with UV detection (HPLC-UV) for the simultaneous quantification of cortisol, cortisone, and corticosterone was developed and validated. The method involved solid-phase extraction (SPE) followed by chromatographic separation using a Nucleosil 100 C-18, 5 µm, 250 × 4 mm i.d. chromatographic column. The mobile phase was binary mixture of acetonitrile and water (30:70 v/v) at a flow rate of 1 mL/min.

Journal of Pharmaceutical and Biomedical Analysis, 2015

The purpose of this work is the evaluation of the nutritional status of patients with cystic fibr... more The purpose of this work is the evaluation of the nutritional status of patients with cystic fibrosis (CF), based on the level of vitamin C in urine and vitamins A and E in serum, using the fast, selective and fully automated micellar electrokinetic capillary chromatographic (MEKC) and microemulsion electrokinetic capillary chromatographic (MEEKC) methods. The optimization of parameters affecting the electrophoretic separation provided adequate separation of the analytes of interest in the short time of 8 min (MEKC) and 20 min (MEEKC). The developed methods were practical applications to evaluate the levels of vitamins A, C and E in real samples from 28 children suffering from cystic fibrosis and from 10 healthy volunteers. Based on the mean concentration values obtained in the two groups, it can be seen that the levels of each vitamin were lower in patients with CF than in healthy volunteers. In the case of vitamin E, these differences in both groups were statistically significant, while the disproportion of concentrations of vitamins A and C in both the studied groups were not so relevant. On the other hand, a principal component analysis (PCA) confirmed that in some patients with CF the concentration of vitamin A was significantly lower than in the control group. Thus, the future evaluation of the status of fat-soluble vitamins in the longer term for the evaluation of the nutritional status of patients with CF should be continued. The presented CE methods can become useful tools for the evaluation of the nutritional status of patients with CF.

Talanta, 2011

A sensitive and rapid liquid chromatographic (LC) method for the simultaneous determination of te... more A sensitive and rapid liquid chromatographic (LC) method for the simultaneous determination of testosterone (T) and epitestosterone (E) in human urine samples has been developed and elaborated. The ratio of the both steroids (T/E) in human urine is a widely used as doping control indicator. A sample pretreatment by solid-phase extraction (SPE) after hydrolysis using 36% hydrochloric acid for determination of total level of T has been applied. Unconjugated (free) form of the both androgens were determined without hydrolysis steps, what makes novelty of the method, because simplifies the proposed procedure. In turn, the measurements of urinary free T and E provided the diagnostic information for excess adrenal production of steroids. The proposed LC assay was evaluated by analyzing a series of urine samples containing T, E and methyltestosterone (MT) as internal standard at the range of concentration 2-300 ng −1 mL of both analyzed hormones. The proposed method was fully validated for specificity, linearity, limits of detection and quantitation, precision and trueness according to the current requirements concerning analytical methods. Interestingly, the developed LC method allows to obtain a sensitive enhancement with respect to UV detection with the quantitation limit for T and E equaled 2 ng mL −1 . The method was selective and reliable for identity and enable to detect changes of endogenous levels of T and E in urine independently of fluctuations characteristic for both analyzed endogenous hormone level in plasma. .pl (L. Konieczna). androgen deficiency in clinical conditions . The normal amounts of total endogenous T and epitestosterone (E) practically measured in healthy male in urine are in the range 30-60 ng mL −1 [11]. T and E and their ratio T/E is stable in males, what was well established . Since 1983, T was forbidden in sports by the International Olympic Committee (IOC). The detection of illicit use of T is currently carried out measuring the ratio between the concentration of T and its isomer E. A ratio of their concentrations (T/E ratio) higher than 4 is considered as potentially indicative of T administration. On the other hand, because the T/E ratio can be artificially modified by the administration of E, a urinary concentration of epitestosterone above 200 ng mL −1 has been established as indicative of its misuse as a masking agent . The World Anti-Doping Agency (WADA) indicated that if the T/E ratio was equal or above 4, or concentration of E higher than 200 ng mL −1 , a confirmation procedure to prove doping would be necessary .

Molecular BioSystems, 2011

A rapid and sensitive reversed-phase liquid chromatographic method (RP-LC) with UV detection has ... more A rapid and sensitive reversed-phase liquid chromatographic method (RP-LC) with UV detection has been developed for the determination of free cortisol, cortisone and corticosterone in human urine. The assay was performed after a solid-phase extraction procedure (SPE) with dexamethasone as the internal standard. Chromatographic separation was carried out on a Nucleosil 100 C 18 analytical column using a mixture of acetonitrile and water (30 : 70, v/v) as a mobile phase at a flow-rate of 1 mL min À1 . Spectrophotometric detection was performed at 240 nm. The method has been validated for accuracy, precision, selectivity, linearity, recovery and stability. The absolute recoveries of glucocorticoids were above 94.6%. The limits of detection (LOD) and quantification (LOQ) were 0.5 and 2 ng mL À1 , respectively, for all analytes. Linearity was confirmed in the range of 2-300 ng mL À1 with a correlation coefficient greater than 0.9997 for all steroid hormones. The proposed method was sensitive, robust and specific allowing reliable quantification of steroid hormones. This method was successfully applied for determination of three endogenous glucocorticoid levels in human urine. The studies were performed on 20 sedentary healthy volunteers in comparison to two socially diversified groups, namely 10 parachutists before and after jump and 10 patients with depression. Pharmacokinetic studies performed on these groups indicated that urinary free cortisol and cortisol-to-cortisone ratios can be treated as biomarkers of stress and depressive disorders.

Journal of Separation Science, 2011

Nowadays, due to the availability of hundreds of brands of reversed-phase liquid chromatographic ... more Nowadays, due to the availability of hundreds of brands of reversed-phase liquid chromatographic columns, the selection of suitable columns can be difficult. Therefore, a good characterization and classification system is very important. Among published papers, the classification system based on quantitative structure-retention relationships and a method developed at the Katholieke Universiteit Leuven also exist. In quantitative structureretention relationships, retention is evaluated in terms of the chemical structure of the analytes and the physicochemical properties of both the stationary and mobile phase. The second system allows to rank columns due to the values of four parameters and the calculation of specific F KUL -values for a reference column and to be compared with others. In this paper, the classification systems based both on quantitative structure-retention relationships and the F KUL -values using principal components analysis were compared. Moreover, the proposed column ranking systems have been checked in clinical practice case considering liquid chromatography determination of six steroid hormones in urine samples. Despite that the matching of both methods is not exactly the same, both classification systems provide simple, reliable and comparable results.

Journal of Pharmaceutical and Biomedical Analysis, 2011

The report describes a new approach enabling simple and rapid multi-residue screening of seven su... more The report describes a new approach enabling simple and rapid multi-residue screening of seven sulfonamides (SAs): sulfamethazine (SMZ), sulfamerazine (SMR), sulfathiazole (STZ), sulfachloropyridazine (SCP), sulfamethoxazole (SMX), sulfacarbamide (SC), and sulfaguanidine (SG); and three amphenicol-type antibiotics: chloramphenicol (CAP), thiamphenicol (TAP), and florfenicol (FF) in animal tissue by micellar electrokinetic chromatography (MEKC). The analytes were isolated from tissue samples through solidphase extraction (with a C 18 cartridges) following protein precipitation with acetonitrile. The evaluated LOD and LOQ values ranged from 1.3 to 7.8 and from 4.5 to 26.1 ng/g, respectively. These values are far lower than the maximum residue limits (MRLs) set by several control authorities. Intra-and inter-day precision data were less than 9.5% and 11.2% for SAs, and 8.4% and 14.9% for amphenicols. Moreover, the method was found accurate, with the recoveries ranging from 86.4% to 109.4%. The absolute recoveries of the analysed drugs were higher than 77.2%. The results obtained in the validation process demonstrate that the developed CE method is suitable for simultaneous determination of SA and amphenicol residues in poultry tissue, with the total run time less than 8 min.

Journal of Pharmaceutical and Biomedical Analysis, 2013

This paper focuses on a comparative study of the column classification system based on the quanti... more This paper focuses on a comparative study of the column classification system based on the quantitative structure-retention relationships (QSRR method) and column performance in real biomedical analysis. The assay was carried out for the LC separation of moclobemide and its metabolites in human plasma, using a set of 24 stationary phases. The QSRR models established for the studied stationary phases were compared with the column test performance results under two chemometric techniques - the principal component analysis (PCA) and the hierarchical clustering analysis (HCA). The study confirmed that the stationary phase classes found closely related by the QSRR approach yielded comparable separation for moclobemide and its metabolites. Therefore, the QSRR method could be considered supportive in the selection of a suitable column for the biomedical analysis offering the selection of similar or dissimilar columns with a relatively higher certainty.

Journal of Chromatography B, 2006

Reversed-phase-high-performance liquid chromatographic method with electrochemical detection has ... more Reversed-phase-high-performance liquid chromatographic method with electrochemical detection has proven to be a highly sensitive and selective method for determination of trace components in complex biological samples, and the electrochemical detector becomes an important alternative tool to ultraviolet and fluorescence detectors. A rapid and sensitive method for the accurate determination of metoclopramide, hydrochlorothiazide, imipramine and diclofenac in serum or plasma samples is described. The method is based on liquid-liquid extraction. The compounds were separated on C-18 column as stationary phase with a different binary mixture as mobile phase. Proposed method was validated with respect to specificity, linearity range, limit of detection and quantitation, precision, accuracy and successfully applied in a pharmacokinetic studies.

Journal of Chromatography A, 2014

This paper focuses on the application of a column classification system based on the Katholieke U... more This paper focuses on the application of a column classification system based on the Katholieke Universiteit Leuven for the characterization of physicochemical properties of core-shell and ultra-high performance liquid chromatographic stationary phases, followed by the verification of the reliability of the obtained column classification in pharmaceutical practice. In the study, 7 stationary phases produced in core-shell technology and 18 ultra-high performance liquid chromatographic columns were chromatographically tested, and ranking lists were built on the F KUL -values calculated against two selected reference columns. In the column performance test, an analysis of alfuzosin in the presence of related substances was carried out using the brands of the stationary phases with the highest ranking positions. Next, a system suitability test as described by the European Pharmacopoeia monograph was performed. Moreover, a study was also performed to achieve a purposeful shortening of the analysis time of the compounds of interest using the selected stationary phases. Finally, it was checked whether methods using core-shell and ultra-high performance liquid chromatographic columns can be an interesting alternative to the high-performance liquid chromatographic method for the analysis of alfuzosin in pharmaceutical practice.

Journal of Chromatography A, 2013

Journal of Chemometrics, 2011

This paper focuses on the application of principal component analysis (PCA) to facilitate the opt... more This paper focuses on the application of principal component analysis (PCA) to facilitate the optimization of the derivatization of oestrogenic steroids-estrone, 17b-estradiol, estriol, 17a-ethinylestradiol and diethylstilbestrol-in order to achieve (1) the complete derivatization of all the hydroxyl groups contained in the structure of the compounds and (2) the greatest effectiveness of this reaction. Six different derivatization reagents were used in this study, whereas 2-methyl-anthracene was applied as the internal standard to evaluate the effectiveness of the reactions. The experimental data were subjected to PCA. With PCA, the dimensionality of the original multivariable data set could be reduced and the selection of optimum conditions for derivatization facilitated. The mixture of 99% N,O-bis(trimethylsilyl)trifluoroacetamide + 1% trimethylchlorosilane and pyridine (1:1, v/v) at 60 C for 30 min has been established as the most convenient and efficient means of derivatizing the aforementioned oestrogenic steroids and diethylstilbestrol; the N-methyl-N-(trimethylsilyl)trifluoroacetamide + pyridine (1:1, v/v) mixture seems to be a promising alternative. The application of PCA for optimizing the derivatization procedure, proposed for the first time in this study, is particularly useful in the development of multicomponent methods across several chemical classes of compounds.

Journal of Analytical Chemistry, 2010

A rapid and sensitive liquid chromatography method with amperometric detection has been developed... more A rapid and sensitive liquid chromatography method with amperometric detection has been developed for the determination of propafenone in serum. Sample preparation based on single extraction with dichloromethane using bupivacaine hydrochloride as internal standard. The compounds were separated on C 18 reversed phase analytical column with the mobile phase composed of methanol-acetonitrile⎯10 mM K 2 HPO 4 (45 : 25 : 30, v/v/v). Analytes were detected electrochemically with the use of amperometric detector. The quantification limit for propafenone in serum was 10 ng/mL. Linearity of the method was con firmed in the range of 10-500 ng/mL with correlation coefficient of 0.9998. Inter day relative standard devi ations (RSD) ranged from 0.27 to 11.9% and intra day RSD equalled from 1.1 to 9.7%. The newly developed method was applied for the monitoring of the drug in blood levels with 18 healthy volunteers taking tablet with propafenone.

Food Analytical Methods, 2014

An analytical method to quantify lincosamide residues (lincomycin and clindamycin) in poultry tis... more An analytical method to quantify lincosamide residues (lincomycin and clindamycin) in poultry tissue samples by micellar electrokinetic capillary chromatography combined with UV detection has been developed and validated. The clean-up procedure with a simple deproteinization and solid-phase extraction was successfully applied for the determination of antibiotics in different edible tissue samples of poultry. The electrophoretic separation was achieved using an uncoated fused silica capillary (57 cm × 75 μm i.d.), voltage 16 kV, temperature 22°C, and the optimal wavelength at 200 nm. The running buffer consisting of 10 mM sodium tetraborate decahydrate (pH 9.3) and 25 mM sodium dodecylsulfate was employed. The validation of the method was performed by evaluation of the analytical parameters: linearity, specificity, precision, and accuracy with limits of detection of 13.2 and 18.5 ng/g, for clindamycin and lincomycin, respectively. Good intermediate precision was obtained with relative standard deviation values less than 12 %. The mean recoveries were 91.2 and 87.7 % for lincomycin and clindamycin, respectively. The obtained results confirm that the proposed method is capable to identify and quantify of lincosamide residues in animal tissues far below maximum residue limit values and could be suitable for routine application in commercial of poultry samples.

ELECTROPHORESIS, 2010

Micellar electrokinetic capillary chromatographic (MEKC) method used for determination of cortiso... more Micellar electrokinetic capillary chromatographic (MEKC) method used for determination of cortisol in urine was developed and elaborated. In turn, the measurements of urinary free cortisol provided the diagnostic information for excess adrenal production of cortisol. MEKC realized by the addition of anionic surfactant sodium dodecyl sulfate (SDS) to the buffer solution, was demonstrated as to be the appropriate mode for the separation of cortisol and dexamethasone used as internal standard. A buffer solution composed of 10 mM sodium tetraborate and 50 mM SDS at pH 8.8 was used. The MEKC assay was evaluated by analyzing a series of urine samples containing cortisol in variable concentrations. The proposed method was validated for specificity, linearity, limits of detection and quantitation, precision and trueness. The quantitation limit for cortisol equaled 5 ng/ml. The method was selective, and reliable for identity and enable to detect changes of endogenous levels of cortisol in urine under different stress situations.

Biomedical …, 2007

... its two metabolites in human plasma and application to pharmacokinetic studies Alina Plenis,*... more ... its two metabolites in human plasma and application to pharmacokinetic studies Alina Plenis,*Aleksandra Chmielewska, Lucyna Konieczna and Henryk Lamparczyk ... Reagents. Aurorix 150 mg tablets were supplied by Hoffmann La Roche Ltd (Basel, Switzerland). ...

Chromatographia, 2013

A new liquid chromatographic (LC) method for simultaneous determination of lidocaine hydrochlorid... more A new liquid chromatographic (LC) method for simultaneous determination of lidocaine hydrochloride (LH) and tribenoside (TR) along with their related compounds in pharmaceutical preparations is described. Satisfactory LC separation of all analytes after the liquid-liquid extraction (LLE) procedure with ethanol was performed on a C 18 column using a gradient elution of a mixture of acetonitrile and 0.1 % orthophosphoric acid as the mobile phase. The procedure was validated according to the ICH guidelines. The limits of detection (LOD) and quantification (LOQ) were 4.36 and 13.21 lg mL -1 for LH, 7.60 and 23.04 lg mL -1 for TR, and below 0.11 and 0.33 lg mL -1 for their impurities, respectively. Intra-and inter-day precision was below 1.97 %, whereas accuracy for all analytes ranged from 98.17 to 101.94 %. The proposed method was sensitive, robust, and specific allowing reliable simultaneous quantification of all mentioned compounds. Moreover, a comparative study of the RP-LC column classification based on the quantitative structure-retention relationships (QSRR) and column selectivity obtained in real pharmaceutical analysis was innovatively applied using factor analysis (FA). In the column performance test, the analysis of LH and TR in the presence of their impurities was carried out according to the developed method with the use of 12 RP-LC stationary phases previously tested under the QSRR conditions. The obtained results confirmed that the classes of the stationary phases selected in accordance with the QSRR models provided comparable separation for LH, TR, and their impurities. Hence, it was concluded that the proposed QSRR approach could be considered a supportive tool in the selection of the suitable column for the pharmaceutical analysis.

Biomedical Chromatography, 2001

A rapid and sensitive reversed-phase high performance liquid chromatographic method has been deve... more A rapid and sensitive reversed-phase high performance liquid chromatographic method has been developed for the determination of metoclopramide in serum. The assay was performed after single extraction with ethyl ether using methyl parahydroxybenzoate as internal standard. Chromatographic separations were performed on C(18) stationary phase with a mobile phase composed of methanol-phosphate buffer pH 3 (30:70 v/v). Analytes were detected electrochemically. The quantification limit for metoclopramide in serum was 2 ng mL(-1). Linearity of the method was confirmed in the range of 5-120 ng mL(-1) (correlation coefficient 0.9998). Within-day relative standard deviations (RSDs) ranged from 0.3 to 5.5% and between-day RSDs from 0.8 to 6.0%. The analytical method was successfully applied for the determination of pharmacokinetic parameters after ingestion of 10 mg dose of metoclopramide. Studies were performed on 18 healthy volunteers of both sexes.

Biomedical Chromatography, 2006

A reversed-phase high-performance liquid chromatographic method with electrochemical detection fo... more A reversed-phase high-performance liquid chromatographic method with electrochemical detection for the quantitative determination of diclofenac potassium in plasma was developed. Naproxen was used as the internal standard. The drug and internal standard were isolated from plasma by extraction with dichloromethane and 2 M hydrochloric acid. Chromatographic separation was performed on a C18 column with methanol-water (68:32, v/v) adjusted to pH 3.2 with phosphoric acid as mobile phase. The oxidation potential for detection was established by constructing a voltammogram for diclofenac. The quantification limit for diclofenac in plasma was 5 ng mL(-1). Linearity of the method was confirmed in the range 5-2000 ng mL(-1), correlation coefficient 0.9998. Within-day relative standard deviations (RSDs) ranged from 0.66 to 14.00% and between-day RSDs from 0.59 to 15.78%. The method was successfully applied for the determination of pharmacokinetic parameters after ingestion of a 50 mg dose of diclofenac. Studies were performed on 18 healthy volunteers of both sexes.