Capillary Electrophoresis Method Research Articles

Development of an eco-friendly capillary electrophoresis method for the simultaneous determination of piperacillin, tazobactam and ibuprofen in plasma samples: application to a pharmacokinetic study in rats.

Piperacillin (PIP) and tazobactam (TAZ) are broad-spectrum beta-lactam antimicrobial agents, which are frequently co-prescribed in intensive care units (ICUs) worldwide. Ibuprofen (IBU) is a potent pain killer which is commonly co-prescribed with PIP and TAZ postoperatively. The combination therapy of PIP, TAZ, and IBU has been administered commonly after surgical procedures to combat aerobic and anaerobic microbes and exert anti-inflammatory and analgesic effects. This study describes, for the first time, the development of a new capillary electrophoresis (CE) method with a photodiode array detector for the simultaneous determination of PIP, TAZ, and IBU in plasma samples. The experimental factors affecting the elution of analytes were carefully optimized. The final analysis was achieved using a fused silica capillary (58 cm effective length and 75 μm ID) and a background electrolyte solution containing a methanol/borax buffer solution (15 mM and pH 9.3) in a ratio of (10 : 90 v/v) with a driving voltage of 30 kV and detection at 210 nm. The relationship between the peak area and concentration was linear from 1 to 200 μg mL-1 for both PIP and TAZ and from 3 to 200 μg mL-1 for TAZ. The method used was thoroughly validated in accordance with the validation requirements set out by the Food and Drug Administration (FDA) for bio-analytical processes. The proposed CE method was employed to conduct pharmacokinetic and bioavailability studies of the drugs in rat models. The pharmacokinetic results revealed that there is a significant impact upon prescribing this combination concurrently when compared to their single administration. To illustrate, the time required to reach their maximum concentrations (T max) was increased by 0.25 h for both PIP and TAZ, whereas it was increased by 0.5 for IBU. When it comes to their maximum concentration (C max), it was increased by 13.7%, 55.5%, and 44% for PIP, TAZ, and IBU, respectively. Furthermore, the bioavailabilities of PIP, TAZ, and IBU were significantly increased by 55.4%, 19.7%, and 35.6%, respectively. These findings require caution when these drugs are co-prescribed as there is a noticeable augmentation in their therapeutic impacts. Additionally, the greenness of the proposed method was assessed by three metric tools. In conclusion, the method is a valuable tool for further studies on drug-drug interaction in humans.

Development, cross-validation and greenness assessment of capillary electrophoresis method for determination of ALP in pharmaceutical dosage forms - an alternative to liquid chromatography.

Breast cancer treatment has made tremendous progress in recent years and new therapies are emerging continuously. Alpelisib (ALP) is a novel phosphoinositide-3-kinase (PI3K) inhibitor recently approved for human receptor-positive, human epidermal growth factor receptor 2-negative, PIK3CA-mutated metastatic breast cancer in combination with fulvestrant. ALP has been the subject of only a limited number of preclinical in vitro and in vivo studies using different chromatographic techniques. However, no research has been published on analyzing ALP using capillary electrophoresis (CE). The absence of pharmacopoeial monographs for ALP in both the European and United States Pharmacopoeias highlights the urgent need to develop a reliable analytical method for its quality control in both industry and regulatory authorities. In this work, we have developed a first-ever CE method for the determination of ALP in pharmaceutical dosage forms in just 1.4 minutes. This was achieved with a 25 mM borate buffer at pH 9.3, 30 kV separation voltage and 30 °C capillary temperature. The proposed method was validated according to the ICH guidelines regarding selectivity, linearity (r = 0.9988), precision (RSD < 5.9%), accuracy (bias < 3.0%) and robustness (RSD < 3.2%). It was applied to the pharmaceutical dosage form of ALP and was shown to be suitable for the reliable determination of ALP. Furthermore, to demonstrate the applicability of the CE as an alternative technique to more commonly used HPLC in the analysis of drugs, cross-validation of CE and HPLC methods was performed. Bland-Altman analysis showed that the average difference in determined concentrations between CE and HPLC over a range of 10-100 μg mL-1 was 0.87 μg mL-1 (p = 0.6390, N = 19) meaning that there is no difference in the performance of CE and HPLC in the determination of ALP in pharmaceutical dosage forms. The environmental impact of both methods was assessed using AGREE software and scores for CE and HPLC were calculated to be 0.74 and 0.51, respectively. Because of equally reliable analytical performance and greener analysis, CE should be considered as an alternative technique to HPLC in the analysis of ALP pharmaceutical dosage forms.

SUB-MINUTE CAPILLARY ZONE ELECTROPHORESIS METHOD FOR DETERMINATION OF HYDROCHLOROTHIAZIDE IN COMBINATION WITH OTHER ACTIVE INGREDIENTS IN NINE DIFFERENT PHARMACEUTICAL SAMPLES

Capillary electrophoresis (CE) methods have unique potential for applications in quality control of pharmaceutical formulations. Here, we show that a single and ultra-fast CE method can be used for the determination of hydrochlorothiazide (HCT) in combination with nine other active ingredients in a single run in different pharmaceutical samples: atenolol (ATE), metoprolol (MET), propranolol (PRO), benazepril (BEN), captopril (CAP), enalapril (ENA), lisinopril (LIS), ramipril (RAM), and valsartan (VAL). This goal was achieved using a single and simple background electrolyte (BGE) composed of 10 mmol L-1 of boric acid with pH adjusted to 9.0 with sodium hydroxide. All samples can be analyzed in less than 1 min with the attainment of good analytical performance, such as high-resolution separation (r &gt; 1.3), low sample and reagents consumption (environmentally friendly method), low relative standard deviation (RSD) values for peak area (&lt; 4.0%) and migration times (&lt; 1.7%), and linear relationships with good correlation coefficients (&gt; 0.995). Furthermore, recovery tests showed good results (100 ± 5%) for all evaluated compounds.

Efficient and fast detection of uric acid based on a colorimetric sensing method.

The uric acid (UA) level is an important physiological indicator of the human body, and its abnormality can lead to a series of diseases. Therefore, the immediate detection of uric acid concentration has broad application prospects. Commonly used methods for the analysis of uric acid include chromatography, high-performance capillary electrophoresis and electrochemical methods. However, these methods have the disadvantages of cumbersome sample pre-treatment, high cost, time-consuming, and the need for experimental instruments and professional operators, which are extremely unfavorable for the detection of uric acid and the diagnosis of related diseases in resource-limited areas. In this study, a portable visualization method was developed for the detection of uric acid using hydrogen peroxide (H2O2) test strips. Uric acid enzyme specifically catalyzes the oxidation of uric acid to produce H2O2, which causes a significant change in the color of the H2O2 test strip. The response has good linearity in the range of 1 ∼ 50 μg mL-1. Thus, it provides a simple, rapid, and cost-effective visualized bioassay for uric acid.

Quantitative separation of polystyrene nanoparticles in environmental matrices with picogram detection limits using capillary electrophoresis.

We developed a capillary electrophoresis method to separate polystyrene particles (PSPs) with different sizes or different surface functionalities. Separations were performed in buffer and 100 mg L-1 clay or 100 mg L-1 Suwanee River humic acid. In all solutions, PSPs were baseline or near-baseline resolved in less than 15 minutes.

Impact of haemoglobin variants on the diagnostic sensitivity of glycated haemoglobin (HbA1c) assay methodologies in sub-Saharan Africa: a laboratory-based method validation study.

the utility of glycated haemoglobin (HbA1c) for the diagnosis and monitoring of diabetes in sub-Saharan Africa is uncertain due to limited data on the performance of the available HbA1c assay methods in this population, which has a high prevalence of haemoglobin variants. We aimed to compare the diagnostic accuracy of the major HbA1c methodologies (Boronate Affinity, Capillary Electrophoresis, High Performance Liquid Chromatography, Immunoassay) in an African population, and assess the impact of the common haemoglobin variant HbAS (sickle cell trait). whole blood samples were obtained from 182 individuals living with type 2 diabetes in Uganda. HbA1c values for each method were compared to average glucose measured over 14 days by continuous glucose monitoring (CGM). To determine concordance, the three HbA1c assay methods were compared to the capillary electrophoresis method. there was a strong correlation between CGM average glucose levels and all four HbA1c methodologies (r=0.81-0.89) which did not differ in those with and without HbAS (present in 37/182 participants). The presence of HbAS did not alter the relationship between HbA1c and CGM glucose for any assay (p for interaction >0.2 for all methods). Diagnostic accuracy for CGM average glucose thresholds of 7 and 10mmol/L was similar across methods (area under the receiver operating characteristic curve 0.80-0.84 and 0.76-0.84 respectively). The maximum bias between the HbA1c assay methodologies was 2 mmol/mol (2.07%). all major HbA1c technologies offer accurate and comparable HbA1c measurement even in this population with high prevalence of haemoglobin variants.

Contactless conductivity detector as a tool for improving universality and sensitivity of capillary electrophoresis-frontal analysis: Proof of concept.

Drug binding to plasma proteins influences processes such as liberation, adsorption, disposition, metabolism, and elimination of drugs, which are thus one of the key steps of a new drug development. As a result, the characterization of drug-protein interactions is an essential part of these time- and money-consuming processes. It is important to determine not only the binding strength and the stoichiometry of interaction, but also the binding site of a drug on a protein molecule, because two drugs with the same binding site can mutually affect free drug concentration. Capillary electrophoresis-frontal analysis with mobility shift affinity capillary electrophoresis is one of the most used affinity capillary electrophoresis methods for the characterization of these interactions. In this study, awell-known sensitivity problem of most capillary electrophoresis-frontal analyses using ultraviolet detection is solved by its combination with contactless conductivity detection, which provided sixfold lower limits of quantitation and detection. Binding parameters of the human serum albumin-salicylic acid model affinity pair were evaluated by this newly developed approach and by the classical approach with ultravioletdetection primarily used for their mutual comparison. The results of both approaches agreed well and are also in agreement with literature data obtained using different techniques.

Comparison of Capillary Zone Electrophoresis with High-pressure Liquid Chromatography in the Evaluation of Hemoglobinopathies

The capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC) methods were compared in terms of HbA2 measurement for the assessment of hemoglobinopathies. CZE was compared with HPLC for the evaluation of patients without hemoglobinopathy (n=321), with β-thalassemia trait (n=113), and with common (HbD-Punjab, E, C, S/A, and S/S) and rare (HbS/D, O-Arap, Lepore, G-Coushata, Setif, Hamadan, Q-Iran, and H) variants (n=21). The reference range for HbA2 was determined by CZE. Among patients without hemoglobinopathy, the median (2.5th-97.5th percentiles) values were 97.4% (97.0-98.0%) and 97.5% (96.6-98.4%) for HbA (p=0.060) and 2.4% (1.6-3.0%) and 2.5% (1.6-3.1%) for HbA2 (p<0.001) by HPLC and CZE, respectively. The reference range for HbA2 was 1.6-3.1% by CZE. In the comparison of methods for HbA2, there was a constant error of 0.255 (confidence interval: 0.062-0.448) and bias of 0.10% (limit of agreement: 0.33-0.53), and higher values were obtained with CZE. A strong correlation was observed between the methods (r=0.782). Interrater agreement was almost perfect for clinical diagnosis (ϰ=0.911). The two methods detected and identified the common variants similarly. All rare variants, except HbH by HPLC and HbS/D by CZE, were detected as separate peaks by both methods. The two methods were in agreement regarding the preliminary identification of β-thalassemia patients. Different Hb variants were detected by both methods but with possible methodological interference for HbA2 measurements. CZE is a reliable and simple alternative for the evaluation of hemoglobinopathies. The standardization of HbA2 measurements should be prioritized as more techniques become available in routine laboratory practice.

Development of a capillary electrophoresis method based on magnetic solid-phase extraction for simultaneous and sensitive detection of eight biogenic amines in foods.

Biogenic amines (BAs) in high concentrations are toxic and may cause a series of health symptoms. A sensitive measurement of BA levels is essential for human health. Capillary electrophoresis (CE) has emerged for the separation of eight BAs due to simple sample preparation and highly efficient separation. However, an important drawback for CE is low sensitivity. Magnetic solid-phase extraction (MSPE) has become a technique of interest owing to its brief operation and low solvent consumption. Hence, MSPE as a pretreatment has great potential to improve CE sensitivity for the analysis of BAs in complex food. Results showed that the Pt-Co-MWCNTs-COOH possessed strong magnetism, good reusability, and high adsorptive ability toward eight biogenic amines based on the hydrogen bonding between the -COOH of Pt-Co-MWCNTs-COOH and -NH2 groups of BAs. Using it as an adsorbent, a magnetic solid-phase extraction coupled with capillary electrophoresis (MSPE-CE) method was developed to effectively extract and sensitively analyze eight BAs. Under optimal conditions, the MSPE-CE method has wide linearities (10.0-1000.0 μg L-1 ) and low limits of detection (1.0-6.1 μg L-1 ). The accuracy of the developed method yielded recovery values from 82.07% to 102.58%. Meanwhile, the BAs contents in two samples were analyzed using the MSPE-CE method, with the results consistent with those detected by a high-performance liquid chromatography method. Given those advantages, the established MSPE-CE method promises the practical guidance of monitoring a variety of BAs and provides a foundation for the detection of other food hazards. © 2023 Society of Chemical Industry.

The establishment of a multiplex fluorescent polymerase chain reaction coupled with capillary electrophoresis analysis technology enables the simultaneous detection of 16 genotypes of human papillomavirus.

The detection and accurate genotyping of human papillomavirus (HPV) infection is critical for preventing and effectively treating cervical cancer. A multiplex fluorescent polymerase chain reaction (PCR) coupled with a capillary electrophoresis method was developed for the simultaneous detection of the 16 most prevalent HPV genotypes. Twenty-five pairs of primers were ultimately selected to ensure that both E and L regions of nine HPV genotypes, as well as the Eregions of seven HPV genotypes could be accurately amplified. This method enables the simultaneous detection and differentiation of 16 HPV genotypes in a single closed-tube reaction, accurately distinguishing products with molecular weight differences >1 bp through capillary electrophoresis. This method demonstrated exceptional accuracy, specificity, and repeatability with a detection limit of 10 copies/μL for all 16 HPV genotypes. Furthermore, 152 cervical swab specimens were obtained to compare the disparities between this approach and Cobas 4800 HPV detection method. The concordance rate and κ value were 90.1% and 0.802, respectively, indicating a high level of agreement. The established detection method was successfully applied to cervical swab specimens for determining HPV genotypes across all levels of cervical lesions, HPV52, 56, 16, and 59 were found to be most prevalent with infection rates of 10.8%, 9.1%, 6.5%, and 6.2%, respectively. This study has successfully established a detection method capable of simultaneously identifying 16 HPV genotypes. This approach can be further applied to HPV vaccine research and surveillance, with the potential for broad applications.

Simultaneous determination of cystine and other free aminothiols in blood plasma using capillary electrophoresis with pH-mediated stacking.

We developed a method of sensitive capillary electrophoresis using UV detection for the determination of certain free aminothiols (reduced cysteinylglycine (rCysGly), cysteine (rCys), glutathione (rGln), and cystine (CysS) in human blood plasma. The reduced thiols were derivatized with N-ethylmaleimide. The plasma was purified from proteins via ultrafiltration. Electrophoretic separation was performed using 115mM Na phosphate with 7.5% (v/v) polyethylene glycol 600, pH 2.3. The in-capillary concentration of the analytes was achieved with a pH gradient created via the preinjection of triethanolamine and postinjection of phosphoric acid. The separation was carried out using a silica capillary (50µm i.d.; total/effective separation length 42/35cm) at a 25kV voltage. The total analysis/regeneration time was 18min. The quantification limits varied from 1.3µM (rCysGly) to 5.4µM (CysS). The accuracy was 95%-99%, and the repeatability and reproducibility were approximately 1.8%-3.8% and 1.9%-5.0%, respectively. An analysis of plasma samples from healthy volunteers (N=41) showed that the mean levels of rCysGly, rCys, rGln, and CysS were 1.64, 10.6, 2.58, and 46.2µM, respectively.

Stereoselective separation of psychoactive substances: Multivariate optimization and validation of a capillary electrophoresis method using carboxymethyl-β-CD/deep eutectic solvent dual system

A comprehensive study was performed to determine an optimum enantioseparation method for fluorine-substituted amphetamine and cathinone derivatives (fluor-amphetamine and fluor-cathinone derivatives), using a binary system consisting of carboxymethyl-β-CD (CM-β-CD) and a deep eutectic solvent (DES), namely choline chloride-ethylene glycol (ChCl-EG). Under this framework, the optimization and modeling of the separation conditions in a binary system were performed with the objective of maximizing resolution and minimizing analysis time. This was achieved through the application of response surface methodology. In particular, the effect of chiral selector concentration and percentage of DES on resolution and analysis time were investigated and optimized using a complete experimental design. The optimum enantioseparation conditions were determined to be 13.84 mM CM-β-CD and 0.15% v/v ChCl-EG for fluorine-substituted amphetamine derivatives and 14.36 mM and 0.75% v/v ChCl-EG for fluorine-substituted cathinone derivatives, respectively. This combination resulted in a baseline separation for eight out of the nine analytes studied. Overall, the results demonstrated the synergistic effect of the CM-β-CD/DES dual system and highlighted the significance of DESs as additives in capillary electrophoresis.

Retracted: Sequence variations of 58 STRs and 94 SNPs in Northeastern Xibe with ForenSeqTM DNA signature prep kit.

Abstract Massively parallel sequencing (MPS) technology has already shown many advantages in forensic DNA typing. In this study, the repeat region (RR) and flanking region (FR) variations were detected at 58 short tandem repeats (STRs) by MPS, which could increase allelic diversity (34.59%) and gene diversity (3.95%) compared with the capillary electrophoresis (CE) method. Six novel RR variants were identified at 5 STRs, and eleven FR variants were found at 8 STRs. Concordance amounted to 99.96% (4598 out of 4600 alleles) between ForenSeq DNA Signature Prep Kit and CE kits, and discordance was due to bioinformatic misinterpretation at DXS7132. Additionally, allele frequencies and forensic parameters of 94 identity-informative single nucleotide polymorphisms (iiSNPs) provided a reference dataset, which held a higher power of discrimination (1–3.4825 × 10−35). A total of 29 FR variants were found at 24 target iiSNPs. The power of the system effectiveness with the combined 27 autosomal STRs by sequence and 94 iiSNPs was added more substantially than that of a single type of marker alone, such as the combined power of discrimination (CPD) and the combined power of exclusion (CPE) achieving 1–7.1358 × 10−65 and 1–4.4803 × 10−21, respectively. Population structure analyses with iiSNPs and additional ancestry-informative SNPs (aiSNPs) demonstrated that Chinese Xibe in the northeast was one of the East Asian populations. At the genetic level, Northeastern Xibe is close to populations where they live, such as Han Chinese and other ethnic minority groups.

Determination of New 4-Aryl-pyrido[1,2-c]pyrimidine Derivatives, Potential Antidepressant Agents with a High Affinity to 5-Hydroxytryptamin 1A Receptor and Serotonin Transporter Protein Receptor, with Capillary Electrophoresis

A novel capillary electrophoresis method was developed for the determination of new 4-aryl-pyrido[1,2-c]pyrimidine derivatives, potential antidepressant agents, in serum. The derivatives have conformationally restricted tryptamine moiety in pharmacophore portion and exhibit high affinity to molecular targets: 5-HT1A receptor and serotonin transporter protein. The separation process was conducted using an eCAP fused-silica capillary, detection wavelength 214 nm, 200 mM phosphate buffer adjusted to pH = 8.0, temperature 20 °C, voltage 5 kV. The proposed method was validated by determining its linearity in the concentration range of 200–1000 ng/mL. A satisfactory linearity was obtained for the method, with R2 from 0.9978 to 0.9999 for all five derivatives and a limit of quantification level from 287.1 to 310.1 ng/mL. The recoveries for all derivatives were in the range from 94.7 to 100%. The speed of obtaining the result of the analysis was only 3 min. The developed method allows to determine all five derivatives both in water solutions and serum.

Innovative analysis of diazepam, zolpidem and their main metabolites in human urine by micelle-to-solvent stacking in capillary electrophoresis

Diazepam and zolpidem are the most widely used medications for managing insomnia. However, significant concerns regarding the potential risks of misuse and abuse problems arose in many literatures. While urine analysis is a valuable diagnostic tool, a challenge arises from the fact that some parent drugs may remain undetectable in urine. This necessitates concurrent monitoring of their metabolites. Here, we described an innovative on-line sample preconcentration technique known as micelle to solvent stacking (MSS) for the analysis of diazepam, zolpidem, and their main metabolites in urine. Several key parameters warrant further discussion to optimize the MSS model, enhancing its performance in terms of sensitivity and resolution. After optimizing the conditions, we conducted a validation test, achieving high correlation coefficients (greater than 0.9977) for intra-day and inter-day regression lines. Additionally, both the relative standard deviation (RSD) and relative error (RE) remained below 6.10% and 12.55%, respectively. The limits of detection (LODs, S/N = 3) for all five analytes ranged from 2.0 to 56 ng/mL. Compared to the conventional capillary zone electrophoresis method, this new approach exhibited remarkable sensitivity enhancements, ranging from 123 to 235-fold. Upon applying this method to actual urine samples from patients, we successfully detected nordiazepam, zolpidem, and its metabolites. This simple and sensitive approach has promising applications in supporting patient medication safety and bolstering forensic investigations.

A novel cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography method for the simultaneous determination of second-generation triazoles in human plasma

In this study, we introduce the first capillary electrophoresis method that combines cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) for the simultaneous and sensitive quantification of voriconazole (VRC), posaconazole (PSC), and isavuconazole (ISV) levels in human plasma. The sensitivity was remarkably improved, with a 5374-fold enhancement compared to the traditional MEKC method. We systematically optimized key parameters affecting sensitivity, resolution, and efficiency. The separation buffer included 100 mM NaH2PO4, 13 % acetonitrile, and 13 % tetrahydrofuran. This was followed by a high-conductivity buffer zone (1 psi, 50 s) of 100 mM NaH2PO4, an extended electrokinetic sample injection (10 kV, 600 s), and analyte sweeping with 100 mM sodium dodecyl sulfate micelles at −20 kV. Under these optimized conditions, the method allowed for an analytical run in 10 min and was validated for linearity (r ≥ 0.9997), precision (%RSD ≤ 8.8 %), and accuracy (%RE ≤ 2.20 %), delivering satisfactory results. The limit of detection was 2.55 ng/mL for ISV, 0.89 ng/mL for PSC, and 1.04 ng/mL for VRC. This method was successfully applied to analyze plasma samples from patients undergoing triazole antifungal treatment, demonstrating its feasibility for clinical testing.

Assessment of energy and biological value of Cherax quadricarinatus meat after feeding crayfish with different types of feed

Cultivation of the Australian red-clawed crayfish Cherax quadricarinatus has become popular in many countries due to the rapid growth rate, high nutritional and biological value of the meat, and quite significant demand among consumers. The aim of our study was to determine the chemical, amino acid and fatty acid composition of Cherax quadricarinatus crayfish meat and its energy value when fed with different types of feed. The fatty acid composition of crayfish meat was determined by the chromatographic method, and the amino acid composition by the capillary electrophoresis method. It was established that when feeding crayfish with the developed Decapodafood feed, the energy value of crayfish meat was 4.3 kcal more than when feeding crayfish with aquarium feed Ancistrus menu. Feeding with Decapodafood promotes a higher content of essential amino acids compared to feeding with commercial aquarium food Ancistrus menu. In particular, a higher content of essential amino acids such as threonine, valine, methionine, lysine in the meat was statistically probable. In addition, a high biological value and digestibility of crayfish meat was found, as the sum of ΣEAA/ΣNEAA in all samples was more than 80%, which is on average 20% more than the standard indicator recommended by FAO/WHO. Feeding crayfish with Decapodafood helps to reduce saturated fatty acids in meat and increase unsaturated ones. In particular, a 1.9 times lower content of lauric acid and 1.5 times lower margaric acid was found in the meat of crayfish fed Decapodafood, compared to crayfish fed Ancistrus menu aquarium food, and myristic and pentadecanoic acid were on average 1.3 times smaller. Among unsaturated fatty acids, a probable increase of 1.4 times was noted for palmitoleic and docosahexaenoic acids, compared to their content in control meat. The content of other polyunsaturated fatty acids (linoleic and eicosapentaenoic), although higher, was insignificant. Therefore, feeding Cherax quadricarinatus crayfish with Decapodafood helps to improve the energy and biological value of the obtained meat, which makes it a highly digestible and delicate product. Key words: Cherax quadricarinatus, crayfish meat, Decapodafood, amino acid, fatty acid composition of meat.

An in-line method for high-throughput screening of protein tyrosine phosphatase receptor type O inhibitors by capillary electrophoresis based on electrophoretically mediated microanalysis

Protein tyrosine phosphatase receptor type O (PTPRO) plays an important role in inflammation-related pathways and has become an emerging drug target. In this study, we developed an in-line capillary electrophoresis (CE) method for the investigation of the enzymatic activity of PTPRO, which was based on electrophoretically mediated microanalysis (EMMA). After a thorough method validation of the optimized conditions, this protocol was successfully employed to determine the kinetics of PTPRO as well as the half-maximal inhibitory concentration (IC50) of two typical PTPRO inhibitors. The final results were consistent with the values obtained through classical ultraviolet–visible (UV–vis) spectrophotometry. Our new method exhibited improved accuracy and reduced consumption, avoiding the disadvantages of traditional methods. This work provides a new strategy for PTPRO enzyme kinetic studies as well as inhibitory activity determination through capillary electrophoresis for the first time.

Quality by design-guided development of a capillary electrophoresis method for the simultaneous chiral purity determination and impurity profiling of tamsulosin.

Analytical Quality by Design principles using the design of experiments were applied for the development of a capillary electrophoresis method for the determination of enantiomeric purity and chemically related impurities of tamsulosin. From initial scouting experiments, a dual cyclodextrin (CD) system composed of sulfated β-CD and carboxymethyl-α-CD was selected as the chiral selector. A fractional factorial resolution V+ design was used for the identification of the critical process parameters, while a face-centered central composite design and Monte Carlo simulations were employed for final optimization and defining the design space of the method. The experimental conditions of the working point were: 30mM sodium phosphate buffer, pH 3.0, containing 40mg/mL sulfated β-CD and 7mg/mL carboxymethyl-α-CD, capillary temperature 18°C, applied voltage -23kV. Following the assessment of robustness by applying a Plackett-Burman design, the method was validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guideline Q2(R1). The method allowed the quantification of the chiral impurity and three other related impurities at the 0.1 % level with acceptable accuracy and precision.

Quantitation of native and forced degraded collagens by capillary zone electrophoresis: Method development and validation.

A new capillary zone electrophoresis method for collagen quantitation was developed and validated according to the International Council for Harmonization guideline Q2 (R1). The Sircol collagen assay and ultraviolet spectrometry were employed as reference methods. Capillary zone electrophoresis enables specific, simple, and fast determination within 9 min. It is less user-dependent and more automated than the Sircol collagen assay. With a limit of detection of 18.0μg/mL, the new method is less sensitive than the Sircol collagen assay, which has a limit of detection of 6.5μg/mL. Nonetheless, capillary zone electrophoresis covers a wider linearity range (50-400μg/mL) compared to the Sircol collagen assay (5-80μg/mL), with similar precision. Additional advantages of capillary zone electrophoresis are the ability to gain information on collagen integrity and to simultaneously determine native and denatured collagens. This approach represents a modern and legitimate alternative to the Sircol collagen assay. The developed method has been successfully applied to the study of three collagen products and samples from forced degradation.