Kris De Braekeleer

Research in Drug Development (RD3)

Pharmacognosy Bioanalysis and Drug Discovery

Research activities

My research are focused on : chemometrics for multivariate analysis of data matrices obtained with hyphenated and spectroscopic techniques in different fields of life science.

Top ten recent articles

Articles dans des revues avec comité de lecture

2023

Quality Control and Authentication of Argan Oils : Application of advanced Analytical Techniques

2022

Response to letter to the editor: “Comments on ‘discrepancies between validated GC‐FID and UHPLC‐DAD methods for the analysis of Δ‐9‐THC and CBD in dried hemp flowers'”

Discrepancies between validated GC‐FID and UHPLC‐DAD methods for the analysis of Δ‐9‐THC and CBD in dried hemp flowers

Relative response factors and multiple regression models in liquid chromatography to quantify low-dosed components using alternative standards—proof of concept: total Δ9-THC content in cannabis flowers using CBD as reference

Contents of amoxillin drugs dispensed in Goma, Democratic Republic of Congo

Benchtop NIR standardization on handheld spectrometers to identify paracetamol tablets

Near-infrared spectroscopy (NIRS) allows innovative applications in terms of quality control, for example, in raw materials verification, in process analytical technology (PAT), and in discrimination between genuine and falsified medicines. The development of small and cheap handheld devices is expanding in the field, while trying to keep similar performances as benchtop instruments have. Considering traceability and quality control of drug compounds, this work is intended to identify 13 different paracetamol tablets on the Belgian market by using NIRS. The performances of a Fourier-transform near-infrared spectroscopy (FT-NIR) benchtop and two handheld NIR spectrometers were investigated comparatively. All spectra were collected through the blister in the reflectance diffuse mode. NIR spectral fingerprints were pretreated and analyzed using principal component analysis (PCA) and classified with soft independent modeling of class analogy (SIMCA). The performances of the spectrometers were evaluated after standardization of the reference benchtop database to the handheld spectrometers. The instrumental response of the benchtop spectrometer was standardized towards the handheld device using the piecewise direct standardization (PDS) algorithm. These investigations permitted the advantages and limitations of NIR data standardization on predictive models to be pointed out. The SIMCA models based on the spectral data of the benchtop (B), handheld 1 (H1), and handheld 2 (H2) instruments had an accuracy of 99.2%, 97.7%, and 96.2%, respectively. The same accuracy was obtained with the models of the transferred benchtop spectra for the H1 and H2 devices. However, adding handheld spectra to the transferred benchtop spectra resulted in models with improved accuracy: from 97.7% to 98.5% for the H1 instrument and from 96.2% to 97.7% for the H2 instrument. The proposed strategy highlights the potential of using a reference database collected by NIRS for pharmaceutical analyses by handheld NIR spectrometers in terms of traceability.

2021

Determination of the quality of metronidazole formulations by near-infrared spectrophotometric analysis

Determination of the quality of metronidazole formulations by near-infrared spectrophotometric analysis

2020

An infrared spectroscopic approach to characterise white powders, easily applicable in the context of drug checking, drug prevention and on‐site analysis

More and more events, such as the summer music festivals, are considering the possibilities for implementing on-site testing of psychoactive drugs in the context of prevention and harm reduction. Although the on-site identification is already implemented by plenty of drug checking services, the required rapid quantitative dosing of the composition of illicit substances is still a missing aspect for a successful harm reduction strategy at events. In this paper, an approach is presented to identify white powders as amphetamine, cocaine, ketamine or others and to estimate the purity of the amphetamine, cocaine and ketamine samples using spectroscopic techniques hyphenated with partial least squares (PLS) modelling. For identification purposes, it was observed that mid-infrared spectroscopy hyphenated with PLS-discriminant analysis allowed the distinction between amphetamine, cocaine, ketamine and other samples and this with a correct classification rate of 93.1% for an external test set. For quantitative estimation, near-infrared spectroscopy was more performant and allowed the estimation of the dosage/purity of the amphetamine, cocaine and ketamine samples with an error of more or less 10% w/w. An easily applicable, practical and cost-effective approach for on-site characterisation of the majority of the psychoactive samples encountered in Belgian nightlife settings based on IR spectroscopy was proposed.

CBD oils on the Belgian market: A validated MRM GC-MS/MS method for routine quality control using QuEChERS sample clean up

Discrimination of legal and illegal Cannabis spp . according to European legislation using near infrared spectroscopy and chemometrics

Spectroscopic techniques combined with chemometrics for fast on-site characterization of suspected illegal antimicrobials

The threats of substandard and falsified (SF) antimicrobials, posed to public health, include serious adverse drug effects, treatment failures and even development of antimicrobial resistance. Next to these issues, it has no doubt that efficient methods for on-site screening are required to avoid that SF antimicrobials reach the patient or even infiltrate the legal supply chain. This study aims to develop a fast on-site screening method for SF antimicrobials using spectroscopic techniques (mid infrared, benchtop near infrared, portable near infrared and Raman spectroscopy) combined with chemometrics. 58 real-life illegal antimicrobials (claiming 18 different antimicrobials and one beta-lactamase inhibitor) confiscated by the Belgian Federal Agency for Medicines and Health Products (FAMHP) and 14 genuine antimicrobials were analyzed and used to build and validate models.Two types of models were developed and validated using supervised chemometric tools. One was used for the identification of the active pharmaceutical ingredients (APIs) by applying partial least squares-discriminant analysis (PLS-DA) and another one was used for the detection of non-compliant (overdosed or underdosed) samples by applying PLS-DA, k-nearest neighbors (k-NN) and soft independent modelling by class analogy (SIMCA). The best model capable of identifying amoxicillin and clavulanic acid (co-amoxiclav), azithromycin, co-trimoxazole and amoxicillin was based on the mid-infrared spectra with a correct classification rate (ccr) of 100%. The optimal model capable of detecting non-compliant samples within the combined group of amoxicillin and co-amoxiclav via SIMCA showed a ccr for the test set of 88% (7/8) using mid infrared or benchtop near infrared spectroscopy. The best model for detecting non-compliant samples within the group of amoxicillin via SIMCA was obtained using mid-infrared or Raman spectra, resulting in a ccr of 80% for the test set (4/5) and a ccr for calibration of 100%. For the group of co-amoxiclav, the optimal models showed a ccr of 100% for the detection of non-compliant samples by applying mid-infrared, benchtop near infrared or portable near infrared spectroscopy. Taken together, the obtained models, hyphenating spectroscopic techniques and chemometrics, enable to easily identify suspected SF antimicrobials and to differentiate non-compliant samples from compliant ones.

A new potential anti‐cancer beta‐carboline derivative decreases the expression levels of key proteins involved in glioma aggressiveness: A proteomic investigation

2018

Determination of three main chlorogenic acids in water extracts of coffee leaves by liquid chromatography coupled to an electrochemical detector

Coffee is a beverage widely consumed in the world. The coffee species most commercialized worldwide are Arabica (Coffea arabica) and Robusta (Coffea canephora). Roasted coffee beans are the most used, but coffee leaves are also consumed as infusion in several countries for traditional medicinal purposes. They contain several interesting phenolic antioxidant compounds mainly belonging to chlorogenic acids (CGAs). In the present work, a liquid chromatography-electrochemical detection (LC-EC) method was developed for the determination of three main chlorogenic acid isomers, namely 3-, 4-, and 5-caffeoylquinic acids (CQA), in coffee leaves aqueous extracts. Samples from eight coffee species, namely; Coffea arabica, Coffea canephora, Coffea liberica, Coffea humilis, Coffea mannii, Coffea charrieriana, Coffea anthonyi, and Coffea liberica var. liberica, were grown and collected in tropical greenhouses. Linearity of the calibration graphs was observed in the range from the limit of quantification to 1.0 × 10−5 M, with R2 equal to 99.9% in all cases. High sensitivity was achieved with a limit of detection of 1.0 × 10−8 M for 3-CQA and 5-CQA (i.e., 3.5 µg/L) and 2.0 × 10−8 M for 4-CQA (i.e., 7.1 µg/L). The chromatographic profile of the samples harvested for each Coffea species was studied comparatively. Obtained raw data were pretreated for baseline variations and shifts in retention times between the chromatographic profiles. Principal Component Analysis (PCA) was applied to the pretreated data. According to the results, three clusters of Coffea species were found. In the water sample extracts, 5-CQA appeared to be the major isomer, and some species contained a very low amount of CQAs. Fluctuations were observed depending on the Coffea species and harvesting period. Significant differences between January and July were noticed regarding CQAs content. The species with the best CQAs/caffeine ratio was identified. The LC-EC data were validated by liquid chromatography-high resolution mass spectrometry (LC-HRMS).

Electrochemical studies of ethoxyquin and its determination in salmon samples by flow injection analysis with an amperometric dual detector

Ethoxyquin (EQ) is an antioxidant widely used in the food industry. Some concerns for human health have been reported since its utilization in animal feed may lead to residues in human food such as salmon samples. This work aimed to investigate the electrochemical behavior of EQ and its major oxidation products namely a dimer of EQ (EQDM) and ethoxyquin quinone imine (EQI) by cyclic voltammetry (CV) at a carbon screen printed electrode (cSPE). The stability of these products and their reactivity against glutathione (GSH) were also studied. Oxidized products and thiol adducts were identified by a microelectrolysis of an EQ solution onto a cSPE in the absence and in the presence of GSH. The products were analyzed off-line, by liquid chromatography coupled to a mass spectrometer (LC-MS). One of the generated product (EQI) was shown to be highly reactive towards GSH. Based on the redox pattern of EQ, a flow injection analysis with a dual cSPE was developed in order to detect in a rapid manner EQ in salmon samples. Since matrix effects were observed, matrix-matched calibration curves with spiked samples were built. A linear response was obtained between 20-100 μM and a limit of detection (LOD) of 7.5 μM (8.2 mg/kg of salmon). Trueness was assessed with recovery assays at three levels of concentration. The recovery was close to 100 %. Precision was determined as RSD (%) with values lower than 6 % in all cases.

Identification of coffee leaves using FT-NIR spectroscopy and SIMCA

Abundant literature has been devoted to coffee beans (green or roasted) chemical description but relatively few studies have been devoted to coffee leaves. Given the fact that coffee leaves are used for food and medicinal consumption, it was of interest to develop a rapid screening method in order to identify coffee leaves taxa. Investigation by Fourier - Transform near infrared spectroscopy (FT-NIRS) was performed on nine Coffea taxa leaves harvested over one year in a tropical greenhouse of the Botanic Garden Meise (Belgium). The only process after leaves harvesting was an effective drying and a homogeneous leaves grinding. FT-NIRS with SIMCA analysis allowed to discriminate the spectral profiles across taxon, aging stage (mature and senescence coffee leaves) and harvest period. This study showed that it was possible (i) to classify the different taxa, (ii) to identify their aging stage and (iii) to identify the harvest period for the mature stage with a correct classification rate of 99%, 100% and 90%, respectively.

2016

Bisacodyl als laxativum in de Belgische apotheek

2012

Ethinylestradiol and levonorgestrel preparations on the Belgian market: A comparitive study

2009

Nifedipine preparations on the Belgian market: A comparitive study

2008

Lisinopril and lisinopril/hydrochlorothiazide preparations on the Belgian market: A comparitive study

Propranolol preparations on the Belgian market: A comparitive study

2006

Fluconazole preparations on the Belgian market: A comparitive study

2005

Piracetam preparations on the Belgian market: A comparitive study

Ranitidine preparations on the Belgian market: A comparitive study

2000

Determination of the end point of a chemical synthesis process using on-line measured mid-infrared spectra

Improved purity assessment of high-performance liquid chromatography diode array detection data for overcoming the presence of the non-linearity artefact

Resolution of multicomponent peaks by multicomponent projection approach, positive matrix factorization and alternating least squares

1999

Application of several modified peak purity assays to real complex multicomponent mixtures by high-performance liquid chromatography with diode-array detection

On-line application of the orthogonal projection approach (OPA) and the soft independent modelling of class analogy approach (SIMCA) for the detection of the end point of a polymorph conversion reaction, by near infrared spectroscopy (NIR)

Nested Designs in Ruggedness testing

1998

Purity assessment and resolution of tetracycline hydrochloride samples using high-performance liquid chromatography with diode array detection

Influence and correction of temperature perturbations on NIR spectra during the monitoring of a polymorph conversion process prior to self-modelling mixture analysis

1997

Evaluation of the orthogonal projection approach (OPA) and the SIMPLISMA approach on the Windig standard spectral data sets