Quantitative analysis of therapeutic peptides by CZE using multiple sample injection in hydrodynamically closed separation system.

Therapeutic peptides have emerged as an innovative and promising class of therapeutic compounds in modern medicine. Synthetic peptide analogs triptorelin and lanreotide are known for their pronounced clinical versatility and potency. In this study, we present the development and validation of novel methods based on capillary zone electrophoresis performed in hydrodynamically closed system (HCS) and paired with ultraviolet detection and repeated injection sample introduction. To the best of our knowledge, we developed the first capillary electrophoresis-based method for the determination of lanreotide, and concurrently, the first HCS method for the determination of triptorelin. Maximal separation efficiency and signal intensity were achieved using background electrolytes composed of 50 mM formic acid with the addition of 0.05% (v/v) methyl-hydroxyethyl cellulose. The proposed methods exhibit favorable performance characteristics, namely, calibration curve (r2 exceeding 0.99), low limits of detection (0.25 µg/mL in a water matrix and 0.5 µg/mL in synthetic urine), acceptable precision (relative standard deviation ranging from 2.2% to 9.6% for intraday repeatability and between 5.2% and 14.9% for interday reproducibility), and accuracy (relative errors falling within the 91.1%-107.8% range). The method for triptorelin determination was then used for its quantification in a commercially available drug dosage form (powder for injection) and in spiked synthetic urine samples. The developed methods were also evaluated according to the novel blue applicability grade index, revealing their superior applicability. The results collectively point out the potential of the proposed methods for both quality control and clinical investigations.

Capillary electrophoresis in the analysis of therapeutic peptides-A review.

Therapeutic peptides are a growing class of innovative drugs with high efficiency and a low risk of adverse effects. These biomolecules fall within the molecular mass range between that of small molecules and proteins. However, their inherent instability and potential for degradation underscore the importance of reliable and effective analytical methods for pharmaceutical quality control, therapeutic drug monitoring, and compliance testing. Liquid chromatography-mass spectrometry (LC-MS) has long time been the "gold standard" conventional method for peptide analysis, but capillary electrophoresis (CE) is increasingly being recognized as a complementary and, in some cases, superior, highly efficient, green, and cost-effective alternative technique. CE can separate peptides composed of different amino acids owing to differences in their net charge and size, determining their migration behavior in an electric field. This review provides a comprehensive overview of therapeutic peptides that have been used in the clinical environment for the last 25 years. It describes the properties, classification, current trends in development, and clinical use of therapeutic peptides. From the analytical point of view, it discusses the challenges associated with the analysis of therapeutic peptides in pharmaceutical and biological matrices, as well as the evaluation of CE as a whole and the comparison with LC methods. The article also highlights the use of microchip electrophoresis, nonaqueous CE, and nonconventional hydrodynamically closed CE systems and their applications. Overall, the article emphasizes the importance of developing new CE-based analytical methods to ensure the high quality, safety, and efficacy of therapeutic peptides in clinical practice.

Capillary zone electrophoresis in combination with UV detection for simultaneous determination of tramadol and paracetamol in pharmaceutical and biological samples.

The aim of the present study is the development and validation of a simple method based on capillary zone electrophoresis coupled with UV detection for simultaneous determination of tramadol and paracetamol in pharmaceutical and biological samples. The background electrolyte was composed of 50 mM ammonium carbonate, which is a type of a non-conventional electrolyte system. The developed method was characterized by suitable validation parameters, such as linearity (coefficient of determination r2 0,995), selectivity or the limit of detection at the level of 0.25 - 0.5 μg/ml. Acceptable values of accuracy and precision were obtained, which were in good agreement with the recommended validation guidelines for analysis of pharmaceutical and biological samples. Detection was performed at a wavelength of 200 nm. The developed method was successfully applied to determine tramadol and paracetamol in various dosage forms and in urine biological samples. Achieved results indicate a potential of the method to be integrated in the common quality control processes of drugs and/or in bioanalysis.

Capillary Electrophoresis-Mass Spectrometry with Multisegment Injection and In-Capillary Preconcentration for High-Throughput and Sensitive Determination of Therapeutic Decapeptide Triptorelin in Pharmaceutical and Biological Matrices.

A capillary electrophoresis-tandem mass spectrometry method with a multisegment injection and an in-capillary field-enhanced sample stacking for determination of therapeutic peptide triptorelin in pharmaceutical and biological matrices was developed. The CE separation conditions were optimized in order to obtain maximal separation efficiency, analytical signal intensity and stability, and minimal adsorption of the analyzed peptide onto the capillary wall (1 M formic acid-HFo, pH 1.88). The implementation of the field-enhanced sample injection into CE improved the value of limit of detection 50 times while the multisegment injection increased the sample throughput three times in comparison to a conventional CE approach. The proposed method was characterized by favorable performance parameters, such as linearity (r2 ≥ 0.99), limit of detection (5 ng mL-1 in water matrix, 25 ng mL-1 in plasma matrix), precision (relative standard deviation, 1.5-9.4% for intraday and 2.3-11.9% for interday reproducibility), or accuracy (relative errors in the range of 80-109%). The FDA-validated method was successfully applied to the analysis of triptorelin in the commercial drug Diphereline® 0.1 mg (powder for injection) and in spiked human plasma samples. Favorable performance parameters along with proven application potentialities indicate the usefulness of the proposed method for its routine use in drug quality control laboratories and for clinical analysis, such as determination of triptorelin levels in plasma (for pharmacokinetic study).