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The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies
Thesis (MSc Pharmacology)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613785010733056 |
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| access_status_str | Open Access |
| author | Mshayise, Nelisiwe |
| author2 | Kellermann, Tracy |
| author_browse | Kellermann, Tracy Mshayise, Nelisiwe |
| author_facet | Kellermann, Tracy Mshayise, Nelisiwe |
| author_sort | Mshayise, Nelisiwe |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc Pharmacology)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134725 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:41:39.515Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134725 The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies Mshayise, Nelisiwe Kellermann, Tracy Decloedt, Eric Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medicine. Division of Clinical Pharmacology. Multidrug-resistant tuberculosis Pediatric pharmacology Anti-infective agents Tuberculosis in children -- Treatment Tandem mass spectrometry Thesis (MSc Pharmacology)--Stellenbosch University, 2025. Mshayise, N. 2025. The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/234d8c49-049e-4b9a-a67d-9d5b7bfa1dc9 ENGLISH ABSTRACT: Background: Recently, carbapenems (ertapenem and meropenem) have been repurposed to treat extensively drug-resistant TB, which requires prolonged therapy. However, clinical pharmacokinetic data are lacking for optimal dosing, especially in children, where doses depend on age and weight. Since the efficacy of carbapenems depends on time above the minimum inhibitory concentration, concentration-time profiles must be monitored. This study developed LC-MS/MS methods to measure the plasma concentrations of meropenem and ertapenem. The ertapenem data obtained will then be applied to a population pharmacokinetic model for model-informed dosing of ertapenem. Methods: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were developed in positive ion mode with transition ions 384.0500→114.1500 for meropenem and 476.0500→114.0000 for ertapenem. A gradient of 10 to 70% B, using mobile phases A (water with 0.1% formic acid) and B (acetonitrile with 0.1% formic acid), was used for retention and elution. A solid-phase extraction was used to extract meropenem and ertapenem from 25 μL plasma. Before storage, 2-(N-Morpholino)ethanesulfonic acid was added at a 1:1 (v/v) ratio with plasma for storage stability of the analytes. Results: The detected carryover of ertapenem required interim wash steps implemented through separate methods. Two LC-MS/MS methods were developed for meropenem and ertapenem, wherein the analytes were retained at 2.6 and 2.8 minutes, respectively. The stock solutions of meropenem and ertapenem remained stable without MES, in the presence of UV light, at room temperature for 24 hours, at 4°C and - 20°C for three days, and at - 80°C for up to seven months. During the first validation, [2H4]-ertapenem as an ISTD did not adequately compensate for meropenem, but the batch passed without it. The stability tests within the batch passed, and the plasma samples of meropenem remained stable with MES at - 80°C for 48 hours and through two freeze-thaw cycles. The method validation for meropenem was discontinued after the first validation. For ertapenem, [2H4]-ertapenem compensated sufficiently, and the complete validation was performed. The accuracy of the calibration STDs of ertapenem ranged between 98.2% and 101.6%, with % CVs between 1.9% to 8.4%. The quality controls had accuracies ranging between 96.2% and 101.0%, with precision between 5.6% and 13.3%. Matrix effects did not affect the quantification of ertapenem. The recovery and process efficiency of the methods were 97.1% and 96.6%%, respectively. Autosampler stability was shown for 29 hours at 4°C. Frozen ertapenem plasma samples remained stable with and without MES for up to 2 months at - 80°C and through three freeze-thaw cycles. Ertapenem was stable in whole blood for up to two hours on-bench, and the presence of 2% haemolysis did not affect the quantification. This method was applied to a pharmacokinetic evaluation of ertapenem in paediatric XDR-TB case studies. Conclusion: An LC-MS/MS method was developed and validated for the quantification of ertapenem from human plasma, over a calibration range of 0.391 to 300 μg/mL. The developed method of ertapenem was used to determine the concentration-time profiles of three paediatric patients with extensively drug-resistant TB. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2026-01-05T12:18:31Z 2026-01-05T12:18:31Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134725 Stellenbosch University xiv, 120 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Multidrug-resistant tuberculosis Pediatric pharmacology Anti-infective agents Tuberculosis in children -- Treatment Tandem mass spectrometry Mshayise, Nelisiwe The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title | The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title_full | The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title_fullStr | The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title_full_unstemmed | The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title_short | The development and validation of an LC-MS/MS method for the quantification of ertapenem in human plasma: application to paediatric XDR-TB case studies |
| title_sort | development and validation of an lc ms ms method for the quantification of ertapenem in human plasma application to paediatric xdr tb case studies |
| topic | Multidrug-resistant tuberculosis Pediatric pharmacology Anti-infective agents Tuberculosis in children -- Treatment Tandem mass spectrometry |
| url | https://scholar.sun.ac.za/handle/10019.1/134725 |
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