Alternative LC–MS–MS Method for Simultaneous Determination of Proguanil, Its Active Metabolite in Human Plasma and Application to a Bioequivalence Study

Multiplex LC-MS/MS assay for simultaneous quantification of artesunate and its active metabolite dihydroartemisinin with pyronaridine, proguanil, cycloguanil, and clindamycin in pharmacokinetic studies

BACKGROUND

Malaria, especially caused by Plasmodium falciparum, remains a major global health concern, particularly in sub-Saharan Africa. To combat rising drug resistance, innovative treatment approaches like triple artemisinin-based combination therapy (TACT) and multi-drug antimalarial combination therapies (MDACTs) are being explored.

METHODS

This study introduces a robust and validated multiplex LC-MS/MS assay for the simultaneous quantification of key antimalarial drugs and their metabolites, including artesunate, dihydroartemisinin, pyronaridine, proguanil, cycloguanil, and clindamycin. Developed in accordance with EMA guidelines, the assay ensures high accuracy, sensitivity, and stability. Serum samples were prepared through a process of protein precipitation with acetonitrile, followed by the evaporation of the supernatant. The resulting residues were then reconstituted in a 50/50 mixture of aqueous 20 mM ammonium formate buffer and methanol for the analysis.

RESULTS

The assay achieves lower limits of quantifications of 1 ng/mL for proguanil, 0.2 ng/mL for cycloguanil, 1 ng/mL for artesunate, 4 ng/mL for dihydroartemisinin, 2 ng/mL for pyronaridine, and 5 ng/mL for clindamycin. The assay was successfully applied in a pharmacokinetic study conducted as part of a clinical trial in Gabon and Ghana, assessing novel drug combinations in both children and adults against a standard of care artemisinin-based combination therapy.

CONCLUSIONS

The developed assay can support the further clinical development of these TACTs and MDACTs, ultimately contributing to enhanced malaria treatment strategies.

Ambient ionization MS for bioanalysis: recent developments and challenges

Ambient ionization MS has become very popular in analytical science and has now evolved as an effective analytical tool in metabolomics, biological tissue imaging, protein and small molecule drug analysis, where biological samples are probed in a rapid and direct fashion with minimal sample preparation at ambient conditions. However, certain inherent challenges continue to hinder the vibrant prospects of these methods for in situ analyses or to replace conventional methods in bioanalysis. This review provides an introduction to the field and its application in bioanalysis, with an emphasis on the most recent developments and applications. Furthermore, ongoing challenges or limitations related to quantitation, sensitivity, selectivity, instrumentation and mass range of these ambient methods will also be discussed.

Application of paper spray–MS in PK studies using sunitinib and benzethonium as model compounds

Aim: Current bioanalytical methods applied in nonclinical PK studies for screening drug candidates demand significant amount of time and resources, hence, the need to develop alternative methods. Results: A proof-of-concept paper spray–MS method for the detection and quantitation of small molecules in plasma has been developed and validated using sunitinib and benzethonium as model compounds. The method includes single oral or intravenous administration of sunitinib to mice and serial micro-volume (20 µl) blood collection at different time intervals. The method is rapid with overall analysis time of 1 min and a full PK profile of sunitinib was obtained from a single mouse. Conclusion: The paper spray–MS approach is simple, sensitive and can potentially enable significant reduction of animal use and cost.