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See detailDevelopment of a quantitative approach based on surface-enhanced Raman chemical imaging (SER-CI)
De Bleye, Charlotte ULg; Sacre, Pierre-Yves ULg; Dumont, Elodie ULg et al

Conference (2013, October 17)

During the last decade, Raman imaging has taken an important place in the pharmaceutical field [1-2]. It enables to acquire a visual representation of samples while quantifying and identifying molecules ... [more ▼]

During the last decade, Raman imaging has taken an important place in the pharmaceutical field [1-2]. It enables to acquire a visual representation of samples while quantifying and identifying molecules of these samples. However, this technique suffers from a lack of sensitivity and the appearance of fluorescence which can limit its pharmaceutical applications. One way to circumvent these limitations is Surface Enhanced Raman chemical imaging (SER-CI) which presents the advantages of Raman imaging and enables to dramatically increase the Raman scattering of molecules adsorbed or very close to metallic surfaces [3]. The number of publications regarding SER-CI in the pharmaceutical field is very limited probably due to the well-known stability and reproducibility problem of SERS and also due to the difficulty to obtain a homogeneous colloids covering of samples surface before SER-CI analyses. In this context, the possibility to develop a quantitative approach using SER-CI on a pharmaceutical model, presented as paracetamol tablet, was studied. The aim was to develop a SER-CI method enabling to quantify 4-aminophenol (4-AP), which is the main impurity of paracetamol actively research for its toxicity, at a concentration below its limit of specification of 1000 ppm [4]. This pharmaceutical model was first investigated using SERS and a quantitative method enabling to quantify 4-AP from 3 to 15 µg mL-1 was developed and validated [5]. Based on these previous results, the possibility to develop quantitative approach to quantify 4-aminophenol in paracetamol tablet using SER-CI was investigated. Different ways to cover the tablets surface by silver colloids were tested and a homogeneity study was performed in order to improve the repeatability of SER-CI analyses. Afterwards, the SER-CI approach was optimized and different spectral intensity normalizations were tested. Finally, a quantitative approach using SER-CI was developed enabling to quantify 4-AP from 0.025% to 0.2% (w/w) in paracetamol tablets. [less ▲]

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See detailDosages quantitaifs de principes actifs dans les formes solides par spectroscopie proche infrarouge: Application pratique au test d'uniformité de teneur des comprimés
Ginot, Yves-Michel; Bernard-Moulin, Patrick; Boiret, Mathieu et al

Conference (2013, October 03)

L'augmentation du nombre de dosages à réaliser dans l'industrie pharmaceutique conduit à rechercher des méthodes alternatives. La spectroscopie proche infrarouge répond précisément à cette demande en ... [more ▼]

L'augmentation du nombre de dosages à réaliser dans l'industrie pharmaceutique conduit à rechercher des méthodes alternatives. La spectroscopie proche infrarouge répond précisément à cette demande en permettant des dosages rapides, non destructifs et respectueux de l'environnement. Le texte publié dans SFSTP Pharma Pratiques en 2010 énonçait la méthodologie à suivre pour développer une technique de dosage de substance active dans une formulation solide de type comprimé par spectroscopie proche infrarouge. Il est apparu intéressant d'illustrer et de compléter les différentes étapes de cette méthodologies au travers d'exemples. [less ▲]

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See detailVibrational spectroscopy as PAT compliant tools
Ziemons, Eric ULg; De Bleye, Charlotte ULg; Chavez, Pierre-François ULg et al

Scientific conference (2013, September 10)

In the last decades, intensive research and development dealing with NIR and Raman spectroscopy have taken place in industrial field, espacially in pharmaceutical industry. This enthusiasm can be ... [more ▼]

In the last decades, intensive research and development dealing with NIR and Raman spectroscopy have taken place in industrial field, espacially in pharmaceutical industry. This enthusiasm can be explained by the fact that this technique are regarded as promising and attractive tools in PAT, R&D and Green Chemistry frameworks. Their advantages such as non-invasive, non-destructive, fast data acquisition, minization of sample preparation step and the use of probes in on-line, in-line and at-line are expected to reach the aims of PAT, R&D and Green Chemistry. [less ▲]

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See detailA new criterion to assess distributional homogeneity in hyperspectral images of solid pharmaceutical dosage forms
Sacre, Pierre-Yves ULg; Lebrun, Pierre ULg; Chavez, Pierre-François ULg et al

Conference (2013, September)

During galenic formulation development, homogeneity of distribution is a critical parameter to check since it may influence activity and safety of the drug. Several techniques exist to assess this ... [more ▼]

During galenic formulation development, homogeneity of distribution is a critical parameter to check since it may influence activity and safety of the drug. Several techniques exist to assess this homogeneity, the most used and recognized being HPLC. However, these techniques are destructive, time consuming and uses a lot of organic solvents. Vibrational spectroscopies are promising green chemistry techniques that may replace HPLC for several analysis tasks thanks of their rapid, non-destructive and non-pollutant characteristics. Raman hyperspectral imaging is a technique of choice for assessing the distributional homogeneity of compounds of interest. Indeed, the combination of both spectroscopic and spatial information provides a detailed knowledge of chemical composition and component distribution. When dealing with hyperspectral imaging, multivariate data analysis is necessary to extract the concentration map of the compound of interest that will be used to assess sample homogeneity. Actually, most authors assess homogeneity using parameters of the histogram of intensities (e.g. mean, skewness and kurtosis). However, this approach does not take into account spatial information and loses the main advantage of imaging. Recently, Rosas et al. proposed a homogeneity index based on the Poole index. However, it necessitates cutting the maps in non-overlapping macropixels and is therefore quickly limited with small maps. To overcome this limitation, we propose a new criterion that combines Continuous Level Moving Blocks and homogeneity curves with a randomization step to assess the distributional homogeneity. This distributional homogeneity index (DHI) enables analysis of hyperspectral maps without apriori knowledge. It has been applied on five pharmaceutical formulations with different blending conditions. The uniformity content values of the API (present at a concentration of 7% w/w) measured by HPLC ranged from RSD: 0.46% to 11.04%. Ten tablets per formulation have been mapped over a region of interest of 4 mm². After extracting pure spectra by MCR-ALS, the concentration maps of the API were computed using classical least squares analysis. DHI have been computed with a hundred simulations for the randomization step for each concentration map. Afterwards, a mean DHI and standard deviation values were computed per formulation. A linear relationship has been observed between the RSD values and the mean DHI. These results enabled us to select the formulation with the best homogeneity. Further experiments are in progress to check whether hyperspectral imaging combined with DHI could be used in routine to assess blending homogeneity of well-known formulations. [less ▲]

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See detailChimie Analytique - Manuel de Travaux Pratiques
Dispas, Amandine ULg; Ziemons, Eric ULg; Hubert, Philippe ULg

Learning material (2013)

Detailed reference viewed: 46 (7 ULg)
See detailAnalyzing spectral data for the selection of a calibration model
Ziemons, Eric ULg; Moonen, François; Hubert, Philippe ULg

Patent (2013)

The invention relates to method of analyzing spectral data for the selection of a calibration model, relating spectra of a substance to physical or chemical parameter of the substance, over a ... [more ▼]

The invention relates to method of analyzing spectral data for the selection of a calibration model, relating spectra of a substance to physical or chemical parameter of the substance, over a predetermined range of the physical or chemical parameter. [less ▲]

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See detailChemical imaging of small molecules from simple to complex matrices: Quantitative approaches based on Surface Enhanced Raman scattering
De Bleye, Charlotte ULg; Sacre, Pierre-Yves ULg; Chavez, Pierre-François ULg et al

Conference (2013, July)

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS ... [more ▼]

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS chemical imaging, presenting a high specificity and sensibility, allows acquiring a visual representation of samples combining spectral and spatial measurements. This technique could become a powerful tool in pharmaceutical and biological analysis enabling to identify and quantify molecules thanks to chemometric evaluation while looking at their distribution or their interactions. In this context, SERS chemical imaging is investigated in detection or quantitative determination of molecules in pharmaceutical and biological matrices. The feasibility of making quantitative measurements using SERS is evaluated on small target molecules models such as 4-aminophenol and lactate. Firstly, a SERS method to quantify 4-aminophenol which is the primary impurity of acetaminophen coming from its degradation during the storage or from its synthesis was developed on a real pharmaceutical formulation. The standard addition method was selected as calibration method in order to take into account the matrix effect coming from the different components of the latter. Despite the well-known stability and repeatability problems of SERS, the method was thoroughly validated by means of accuracy profiles as decision tool. Moreover, this validation methodology allowed to define a first estimation of the real analytical performance of the technique. Secondly, the detection of lactate, which is a critical metabolite implicated in several metabolic disorders, was successfully tested in the physiological concentration in a simple matrix. Preliminary results for the determination of this metabolic biomarker were also very promising allowing to consider more complex matrices. Based on these results, SERS chemical imaging was implemented to detect 4-aminophenol in a pharmaceutical tablet formerly pulverised by a SERS substrate. Through this imaging technique, it was not only possible to detect the presence of the impurity at the limit of specification of 0.1% (w/w) but it was also possible to differentiate tablets comprising different concentrations of the latter. These promising results represent the first step towards quantitative measurements using SERS chemical imaging. [less ▲]

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See detailValidation methodologies of near infrared spectroscopy methods in pharmaceutical applications
Chavez, Pierre-François ULg; De Bleye, Charlotte ULg; Sacre, Pierre-Yves ULg et al

in European Pharmaceutical Review (2013), 18(1), 3-6

As any analytical methods, a mandatory step at the end of the development of a near infrared spectroscopy (NIRS) method is the validation. This step enables to give enough guarantees that each future ... [more ▼]

As any analytical methods, a mandatory step at the end of the development of a near infrared spectroscopy (NIRS) method is the validation. This step enables to give enough guarantees that each future results coming from the application of the method in routine will be closed enough to the true value. However, from the literature, a minority of NIRS methods are thoroughly validated despite of the guidelines published by different group and regulatory authorities to help analyst to adequately decide if his method can be considered as valid. In this context, the aim of this review is to offer a critical overview of the different validation methodologies applied to assess the validity of quantitative methods using near infrared spectroscopy used in the field of pharmacy. [less ▲]

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See detailATR-IR and Raman spectroscopic study of interaction between major calixarene derivatives and oral anticoagulants
Tiuca, Ioana; Saponar, Alina; Bodoki, Andreea et al

in Farmacia (2013), 61(5), 874-882

In this study we analyzed by ATR-IR and Raman spectroscopy the interaction between six major calixarene derivatives and two anticoagulants: warfarin and acenocoumarol. The six calixarene derivatives were ... [more ▼]

In this study we analyzed by ATR-IR and Raman spectroscopy the interaction between six major calixarene derivatives and two anticoagulants: warfarin and acenocoumarol. The six calixarene derivatives were: p-tert-butyl-calix[4]arene (C4), p-tert- butyl-calix[6]arene (C6) and p-tert-butyl-calix[8]arene (C8) and their ethyl-ester- derivatives: tetraester-p-tert-butyl-calix[4]arene (C4Es4), hexaester-p-tert-butyl- calix[6]arene (C6Es6), octaester-p-tert-butyl-calix[8]arene (C8Es8). The results showed the most intense interaction in terms of complex formation for the C6-acenocoumarol couple and for the C6-warfarin couple, respectively. [less ▲]

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See detailPAT tools for the control of co-extrusion implants manufacturing process
Krier, Fabrice ULg; Mantanus, Jérome; Sacre, Pierre-Yves ULg et al

in International Journal of Pharmaceutics (2013), 458

Hot melt extrusion is a novel pharmaceutical manufacturing process technique. In this study, we identified four Critical Quality Attributes (CQAs) of the implant manufacturing process by hot melt ... [more ▼]

Hot melt extrusion is a novel pharmaceutical manufacturing process technique. In this study, we identified four Critical Quality Attributes (CQAs) of the implant manufacturing process by hot melt extrusion: the implant diameter, the quantity of the Active Pharmaceutical Ingredient (API), the homogeneity distribution of API and the thickness of the membrane. We controlled the implant diameter and the quantity of API in-line with a laser measurement, NIR and Raman spectroscopy, respectively. These two different spectroscopic techniques provided comparable results. In fact, the RMSEC and RMSECV were very close in each PAT technique but NIR spectroscopy was easier to use and less sensitive to external changes. For the control of the homogeneity of API distribution and the thickness of the membrane, we used successfully Raman spectroscopy imaging. These PAT tools help reducing analysis time. [less ▲]

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See detailUsefulness of Information Criteria for the Selection of Calibration Curves
Rozet, Eric ULg; Ziemons, Eric ULg; Marini Djang'Eing'A, Roland ULg et al

in Analytical Chemistry (2013), 85

The reliability of analytical results obtained with quantitative analytical methods is highly dependant upon the selection of the adequate model used as calibration curve. To select the adequate response ... [more ▼]

The reliability of analytical results obtained with quantitative analytical methods is highly dependant upon the selection of the adequate model used as calibration curve. To select the adequate response function or model the most used and known parameter is the determination coefficient R². However it is well known that it suffers many inconvenient, such as leading to overfitting the data. A solution proposed is to use the adjusted determination coefficient R²adj that aims at reducing this problem. However there is another family of criteria that exists to allow the selection of an adequate model: the information criteria AIC, AICc and BIC. These criteria have rarely been used in analytical chemistry to select the adequate calibration curve. This works aims at assessing the performance of the statistical information criteria as well as R² and R²adj for the selection of an adequate calibration curve. They are applied to several analytical methods covering liquid chromatographic methods as well as electrophoretic ones involved in the analysis of active substances in biological fluids or aimed at quantifying impurities in drug substances. In addition, Monte-Carlo simulations are performed to assess the efficacy of these statistical criteria to select the adequate calibration curve. [less ▲]

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See detailUse of Raman spectrometry in the pharmaceutical field
Michelet, Alexandre; Boiret, Mathieu; Lemhachheche, Fatima et al

in STP Pharma Pratiques (2013), 23(2), 97-117

This document sets out the theoretical and practical fundamentals to guide users in the imple- mentation of Raman spectroscopy in industry or the university-hospital sector. It describes the principle of ... [more ▼]

This document sets out the theoretical and practical fundamentals to guide users in the imple- mentation of Raman spectroscopy in industry or the university-hospital sector. It describes the principle of this technique and currently available instruments. Since Raman spectrometers are used in a regulated context, the methodology of instru- ment qualification is discussed. Different types of applications encountered in the pharmaceutical field are presented: process monitoring, searching for and detecting counterfeits, and identifying raw materials on receipt. [less ▲]

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