Enzymatic but not compensated Jaffe methods reach the desirable specifications of NKDEP at normal levels of creatinine. Results of the French multicentric evaluation

in Clinica Chimica Acta (in press)

The French Society of Clinical Biochemistry conducted this study to compare the accuracy and performances of the best creatinine enzymatic assays and the compensated Jaffe methods from the same ... [more ▼]

The French Society of Clinical Biochemistry conducted this study to compare the accuracy and performances of the best creatinine enzymatic assays and the compensated Jaffe methods from the same manufacturers. Creatinine was measured in 3 serum pools with creatinine levels of 35.9 ± 0.9 μmol/L, 74.4 ± 1.4 μmol/L, and 97.9 ± 1.7 μmol/L (IDMS determination). The performances of the assays (total error that includes the contribution of bias and imprecision) were evaluated using Monte-Carlo simulations and compared against desirable NKDEP criteria. The enzymatic assays always fell within the desirable total Error of 7.6%. By contrast, this requirement was never obtained for the compensated Jaffe methods at the critical level of 74.4 ± 1.4 μmol/L. Only the compensated Jaffe creatinine on Olympus analyzer reached this specification at 35.9 ± 0.9 and 97.9 ± 1.7 μmol/L levels. This study demonstrates that, despite substantial improvement regarding traceability to the IDMS reference method and precision, compensated Jaffe creatinine methods, by contrast to enzymatic ones, do not reach the desirable specifications of NKDEP at normal levels of creatinine. [less ▲]

Chemical imaging of small molecules from simple to complex matrices: Quantitative approches based on Surface Enhanced Raman scattering

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 ▲]

Optimisation robuste de méthodes SFC par une approche de type design space

Conference (2013, June)

MEASURING VARIABILITY SOURCES IN NMR METABOLOMIC STUDIES

Conference (2013, May 13)

Due to the huge amount of information available in NMR spectra obtained from the analysis of metabolomic experiments, multivariate analysis such as Principal Component Analysis (PCA) are required to ... [more ▼]

Due to the huge amount of information available in NMR spectra obtained from the analysis of metabolomic experiments, multivariate analysis such as Principal Component Analysis (PCA) are required to understand the influence of treatments over the metabolites [1]. However, many experiments in metabolomics studies have more complexes variability structures than simply comparing several treatments: they may include time effects, biological effects such as diet or hormonal status, and other blocking factors or variability sources: samples stability, age of the individuals, pH of a buffer, days of acquisition, and so on. Metabolomic data analysis needs to extract from the spectral data matrix the variations linked to a change indicated in the factor of interest. However other sources of variability may impair this objective. This stresses the importance to discover the sources of variability of the spectral metabolomic data using appropriate methodology. Classically, to analyze such data analysis of variance (ANOVA) or multivariate ANOVA (MANOVA) [2] is used. However direct application of these methodologies to NMR spectra obtained from structured metabolomics studies is inappropriate or impossible. More complex data analyses methodologies are required to understand the importance of the various factors implied in the experiments and to provide a measure of their variance components. Three related methodologies have been proposed to achieve this: ASCA [3], ANOVA-PCA [4] and AComDim [5]. The ASCA and ANOVA-PCA methodologies combine first an analysis of variance step (ANOVA) and then a PCA step. The AComDim one adds to the output of the ANOVA-PCA step a multi-block analysis. In this presentation, the usefulness and applicability of these advanced techniques to data analysis of NMR metabolomic spectra are provided to highlight the increase of knowledge gained and the estimation of main sources of variability arising in an experimental setup. Two NMR databases will be used [6]. The first one concerns human serum analyzed by 1H-NMR where three random factors are present: day of measurement (3 days), sample (2 samples per individual) and replication of analyses as well as two fixed controlled factors, time of measurement after thawing (2 times) and two protein suppression methods for the spectral pre-treatment. The second database is about the 1H-NMR analyses of rats’ urine where two different concentrations of citrate and of hippurate were deliberately added and three other sources of variability are present: urine pool diluted or not diluted, repetitions of analyses, days of analyses (three days), as well as two different spectral pre-treatment procedures. [less ▲]

Validation methodologies of near infrared spectroscopy methods in pharmaceutical applications

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 ▲]

Methodology for the Validation of Analytical Methods involved in Uniformity of Dosage Units tests

in Analytica Chimica Acta (2013), 760

Validation of analytical methods is required prior to their routine use. In addition, the current implementation of the Quality by Design (QbD) framework in the pharmaceutical industries aims at improving ... [more ▼]

Validation of analytical methods is required prior to their routine use. In addition, the current implementation of the Quality by Design (QbD) framework in the pharmaceutical industries aims at improving the quality of the end products starting from its early design stage. However, no regulatory guideline or none of the published methodologies to assess method validation propose decision methodologies that effectively take into account the final purpose of developed analytical methods. In this work a solution is proposed for the specific case of validating analytical methods involved in the assessment of the Content Uniformity or Uniformity of Dosage Units of a batch of pharmaceutical drug products as proposed in the European or US pharmacopoeias. This methodology uses statistical tolerance intervals as decision tools. Moreover it adequately defines the Analytical Target Profile of analytical methods in order to obtain analytical methods that allow to make correct decisions about Content Uniformity or Uniformity of Dosage Units with high probability. The applicability of the proposed methodology is further illustrated using an HPLC-UV assay as well as a Near Infra-Red Spectrophotometric method. [less ▲]

Implementation of a Design Space Approach for Enantiomeric Separations in Polar Organic Solvent Chromatography

in Journal of Pharmaceutical & Biomedical Analysis (2013), 74

This paper focuses on implementing a Design Space approach and on the critical process parameters (CPPs) to consider when applying the Quality by Design (QbD) concepts outlined in ICH Q8(R2), Q9 and Q10 ... [more ▼]

This paper focuses on implementing a Design Space approach and on the critical process parameters (CPPs) to consider when applying the Quality by Design (QbD) concepts outlined in ICH Q8(R2), Q9 and Q10 to analytical method development and optimization for three chiral compounds developed as modulators of small conductance calcium-activated potassium (SK) channels. In this sense, an HPLC method using a polysaccharide-based stationary phase containing a cellulose tris (4-chloro-3-methylphenylcarbamate) chiral selector in polar organic solvent chromatography mode was considered. The effects of trifluoroacetic acid (TFA) and n-hexane concentration in an acetonitrile (MeCN) mobile phase were investigated under a wide range of column temperatures. Good correlations were found between the observed data obtained after using a central composite design and the expected chromatographic behaviours predicted by applying the design of experiments-design space (DoE-DS) methodology. The critical quality attribute represented here by the separation criterion (Scrit) allowed assessing the quality of the enantioseparation. Baseline separation for the compounds of interest in an analysis time of less than 20 minutes was possible due to the original and powerful tools applied which facilitated an enhanced method comprehension. Finally, the advantage of the DoE-DS approach resides in granting the possibility to concurrently assess robustness and identify the optimal conditions which are compound dependent. [less ▲]

APPLICATION OF AN INNOVATIVE DESIGN SPACE OPTIMIZATION STRATEGY TO THE DEVELOPMENT OF LC METHODS TO COMBAT POTENTIALLY COUNTERFEIT NONSTEROIDAL ANTIINFLAMMATORY DRUGS

in Journal of Chromatography. A (2012), 1263

In the context of the battle against counterfeit medicines, an innovative methodology has been used to develop rapid and specific high performance liquid chromatographic methods to detect and determine 18 ... [more ▼]

In the context of the battle against counterfeit medicines, an innovative methodology has been used to develop rapid and specific high performance liquid chromatographic methods to detect and determine 18 non-steroidal anti-inflammatory drugs, 5 pharmaceutical conservatives, paracetamol, chlorzoxazone, caffeine and salicylic acid. These molecules are commonly encountered alone or in combination on the market. Regrettably, a significant proportion of these consumed medicines are counterfeit or substandard, with a strong negative impact in countries of Central Africa. In this context, an innovative design space optimization strategy was successfully applied to the development of LC screening methods allowing the detection of substandard or counterfeit medicines. Using the results of a unique experimental design, the design spaces of 5 potentially relevant HPLC methods have been developed, and transferred to an ultra high performance liquid chromatographic system to evaluate the robustness of the predicted DS while providing rapid methods of analysis. Moreover, one of the methods has been fully validated using the accuracy profile as decision tool, and was then used for the quantitative determination of three active ingredients and one impurity in a common and widely used pharmaceutical formulation. The method was applied to 5 pharmaceuticals sold in the Democratic Republic of Congo. None of these pharmaceuticals was found compliant to the European Medicines Agency specifications [less ▲]

First Application of an Innovative Design Space Optimization Strategy for the Development of a LC/MS Method

Poster (2012, June 20)

Development of near infrared spectroscopic methods using desirability indexes: How to select the most appropriate calibration model

Conference (2012, May 10)

In the last decade, considerable research and developments dealing with near infrared spectroscopy (NIRS) have taken place in industrial field, especially in pharmaceutical industry. This enthusiasm can ... [more ▼]

In the last decade, considerable research and developments dealing with near infrared spectroscopy (NIRS) have taken place in industrial field, especially in pharmaceutical industry. This enthusiasm can be explained by the fact that NIRS is regarded as promising and attractive tool in Process Analytical Technology (PAT) and Green Chemistry frameworks. Taking into account its non-invasive, non-destructive character, fast data acquisition and the use of probes in on-line, in-line and at-lines, this technique is expected to reach the aims of the latters. However, the development of a NIR quantitative method is not straightforward in comparison with conventional analytical techniques. Its development requires time-consuming reference methods, chemometrics and iterative heuristic approaches to build a model allowing the prediction of the analyte of interest according to the acceptance criteria consistent with the intended use of the method. Facing to the lack of objective decision rule of the traditional chemometric criteria such as R2, RMSEC, RMSECV and RMSEP, it is essential to develop innovative approaches for the selection of the most appropriate calibration model from a models plurality. In this context, a methodology using desirability indexes, such as the Fitting Model Index (FMI), based on tolerance intervals was developed in order to increase significantly the objectivity of the decision process. This latter allows to reduce dramatically the development and the validation steps and thus could ease the implementation of NIR spectroscopy in pharmaceutical industry. [less ▲]