Target site bioanalysis and pharmacokinetics of antileishmanial drugs
Authors:   , Roseboom Ignace Charles 
Published: February 2023

This thesis focuses on bioanalytical method development and validation of
antileishmanial drugs amphotericin B, miltefosine, and paromomycin in human
plasma and human skin tissue followed by clinical target site pharmacokinetic
outcomes induced by these developed bioanalytical methods.

Chapter 1 provides an overview of bioanalytical quantification methods
of the most relevant antileishmanial used in human pharmacokinetic
studies and clinical trials. It covers (liposomal) amphotericin B, miltefosine,
paromomycin, pentamidine and pentavalent antimonials and summarizes
sample preparation, calibration model, separation, and detection methods in
various human matrices from identified published method validations and
included future perspectives in the development of antileishmanial bioanalysis.

Chapter 2 presents the development and validation of a modern bioanalytical
method for the quantification of paromomycin in human plasma using ion-pair
ultra-high performance liquid chromatography tandem mass spectrometry.
It was the first bioanalytical assay that employed a stable isotope labelled
internal standard in the quantification of paromomycin. The relevance
of developing a sensitive method for the quantification of paromomycin
in human plasma is discussed, furthermore its supporting role in clinical
pharmacokinetic studies in patients suffering from visceral leishmaniasis in Kenya.

Chapter 3 discusses and presents target-site bioanalytical methods for the
quantification of antileishmanial drugs in human skin tissue. Chapter 3.1 provides
an overview of existing skin tissue sample pre-treatment and homogenization
techniques for quantification of pharmaceutical compounds. It discusses the
advantages and disadvantages of certain homogenization techniques relative to the
accuracy and recovery from skin tissue of the bioanalytical method. In chapter 3.2
the development and validation of a bioanalytical method for the quantification of
miltefosine in human skin tissue is presented. It describes a detailed development
of a homogenization method employing enzymatic digestion by collagenase A
for human skin tissue sample processing. Furthermore, its clinical applicability to
target-site pharmacokinetic studies in post-kala azar dermal leishmaniasis patients in
Bangladesh is demonstrated. Chapter 3.3 focuses on the development and validation
of a bioanalytical method for the quantification of amphotericin B in human skin
tissue with a clinical application in post-kala azar dermal leishmaniasis patients in
India. Finally, chapter 3.4 provides the development and validation of a bioanalytical
method for the quantification of paromomycin in human skin tissue and a clinical
application in a pharmacokinetic study in post-kala-azar dermal leishmaniasis
patients in Sudan.

Chapter 4 explores the pharmacokinetic outcomes of target-site pharmacokinetic
studies employing human skin tissue data. Chapter 4.1 evaluates miltefosine
pharmacokinetic and pharmacodynamic outcomes and presents the first skin tissue
model characterizing the distribution of miltefosine from blood-based matrices
to skin tissue from patients suffering from post-kala azar dermal leishmaniasis
in India and Bangladesh. Chapter 4.2 presents a pharmacokinetic model for
liposomal amphotericin B in both human plasma and skin tissue, exploring the
target-site exposure and distribution of this antileishmanial drug based on clinical
pharmacokinetic data of patients suffering from post-kala azar dermal leishmaniasis
in India and Bangladesh.

Chapter 5 summarizes and concludes the thesis and furthermore presents the
authors’ views on future perspectives for the development of bioanalytical methods
for antileishmanial drugs.