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Chemometrics applied to spectroscopic measurements such as near-infrared are gaining more and more importance for quality control of pharmaceutical products. Handheld near-infrared devices show great promise as a medicines quality screening technique for post-marketing surveillance. These devices are able to detect substandard and falsified medicines in pharmaceutical supply chains and enable rapid action before these medicines reach patients. The instrumental and environmental changes, expected or not, can adversely affect the analytical performances of prediction models developed for routine applications. Based on a previous study, PLS prediction models were developed and validated on three similar handheld NIR transmission spectrophotometers of the same model and from same company. These models have shown to be effective in analyzing metformin tablet samples, but significant spectral differences between handheld systems complicated their deployment for routine analysis. In this study, different strategies have been applied and compared to correct the instrumental variations, including global modelling (GM) and calibration transfer methods (Direct Standardization, DS; Spectral Space Transformation, SST and Slope/Bias correction, SBC), considering the RMSEP and the accuracy profile as assessment criteria. The transfer methods showed good capabilities to maintain the predictive performances comparable to that of the global modelling approach, except for a remaining slight bias. This approach is interesting since very few standardization samples are required to develop an adequate transfer model. GM, SST and SBC were able to correct/handle drifts in the spectral responses of different handheld instruments and thus may help to avoid the need for a long, laborious, and costly full recalibration process due to inter-instrument variations.

In recent decades, more than 15% of the antimalarials marketed in low- and middle-income countries have been of poor quality, in which quinoline derivatives and quinine-based formulations account for 21%. Near infrared spectroscopy (NIR) was chosen for its fast and inexpensive test properties as well as the ability of using handheld devices to monitor drugs directly on the field. Data driven - soft independent modeling of class analogy (DD-SIMCA) and partial least squares (PLS) regression models were developed for qualitative and quantitative purpose, respectively. The specificity and selectivity tests were performed using the DD-SIMCA models on the placebo, the quinidine and cinchonine standard samples. Then, PLS regression methods have been developed and validated for the quality control of quinine dosage forms manufactured by a major local manufacturer in the Democratic Republic of Congo (DRC). Calibration and validation samples were prepared by dissolving quinine sulfate / quinine hydrochloride in the presence of excipients in HCl 1 M. The opportunity to work with dissolved quinine with a cheap and readily available medium in low- and middle-income countries allowed analysis of different pharmaceutical forms (oral drops, solutions for injection and tablets) with the same regression model. DD-SIMCA models have demonstrated, for both equipment, perfect authentication of quinine and good discrimination of the two alkaloids close to quinine namely cinchonine and quinidine. The NIR PLS regression models were successfully validated using the total error approach with acceptance limits set at ± 10% with a risk level of 5%. The predictive performance of the methods developed was tested in terms of robustness.

Over the last decade, the growth of the global pharmaceutical market has led to an overall increase of substandard and falsified drugs especially on the African market (or emerging countries). Recently, several methods using handheld/portable vibrational spectroscopy have been developed for rapid and on-field drug analysis. The objective of this work was to evaluate the performances of various NIR and Raman handheld spectrophotometers in specific brand identification of medicines through their primary packaging. Three groups of drug samples (artemether-lumefantrine, paracetamol and ibuprofen) were used in tablet or capsule forms. In order to perform a critical comparison, the analytical performances of the two analytical systems were compared statistically using three methods: hierarchical clustering algorithm (HCA), data-driven soft independent modelling of class analogy (DD-SIMCA) and hit quality index (HQI). The overall results show good detection abilities for NIR systems compared to Raman systems based on Matthews's correlation coefficients, generally close to one. Raman systems are less sensitive to the physical state of the samples than the NIR systems, it also suffers of the auto-fluorescence phenomenon and the signal of highly dosed active pharmaceutical ingredient (e.g. paracetamol or lumefantrine) may mask the signal of low-dosed and weaker Raman active compounds (e.g. artemether). Hence, Raman systems are less effective for specific product identification purposes but are interesting in the context of falsification because they allow a visual interpretation of the spectral signature (presence or absence of API).

Graphical abstract, Highlights • Falsified chloroquine phosphate tablets were analyzed in the context of Covid-19 pandemic. • Handheld Raman spectroscopy, Raman hyperspectral imaging and HPLC were performed. • Low levels of chloroquine phosphate, substitution of API and presence of non-declared API were detected. • Raman spectroscopy and Raman hyperspectral imaging are interesting techniques for the of analysis of SF medicines., The proliferation of falsified medicines can cause serious public health issues, particularly in the context of a global pandemic such as the actual COVID-19 pandemic. Our study involved eight chloroquine phosphate medicines seized in Cameroon, Democratic Republic of Congo and Niger during March and May 2020. These suspect samples were first analyzed in a screening phase using field tools such as handheld Raman spectroscopy (TruScan) and then in a confirmation phase using laboratory tools such as hyperspectral Raman imaging and High Performance Liquid Chromatography (HPLC). The results confirmed the falsified nature of the samples, highlighting the presence of metronidazole at low dose in four samples (16.6, 15.2, 15.2 and 14.5 mg/tab), too low levels of chloroquine in two samples (2.4 and 20.2 mg/tab), and substitution of chloroquine phosphate by paracetamol in one sample (255.7 mg/tab). The results also confirmed that four samples had been adulterated with paracetamol in trace amounts and two of them presented traces of chloramphenicol.

Triple beta decay of 150Nd to the ground and excited states of 150Eu and quadruple beta decay of 150Nd to the excited states of 150Gd have been studied using a 400 cm3 low-background HPGe detector. A half-life limit for the quadruple beta decay to the 0 1 + state of 150Gd was found to be T1/2(0v + 4v) > 8.7 × 1020 yr (90% C.L.). For other (0v+4v) transitions to the excited states limits for the first time have been obtained at the level of (6.1 − 9.5) × 1020 yr (90% C.L.). We report here also the results for the first search for triple beta decay to the ground and excited final states of 150Eu, T 1/2(0v + 3v) > (0.04 − 4.8) × 1020 yr (90% C.L.).

The double-beta decay of 82Se to the 0 1 + excited state of 82Kr has been studied with the NEMO-3 detector using 0.93 kg of enriched 82Se measured for 4.75 y, corresponding to an exposure of 4.42 kg⋅y. A dedicated analysis to reconstruct the γ-rays has been performed to search for events in the 2e2γ channel. No evidence of a 2 ν β β decay to the 0 1 + state has been observed and a limit of T 1 / 2 2 ν ( Se 82 , 0 g s + → 0 1 + ) > 1.3 × 10 21 y at 90% CL has been set. Concerning the 0 ν β β decay to the 0 1 + state, a limit for this decay has been obtained with T 1 / 2 0 ν ( Se 82 , 0 g s + → 0 1 + ) > 2.3 × 10 22 y at 90% CL, independently from the 2 ν β β decay process. These results are obtained for the first time with a tracko-calo detector, reconstructing every particle in the final state.

The distributional homogeneity of chemicals is a key parameter of solid pharmaceutical formulations. Indeed, it may affect the efficacy of the drug and consequently its safety. Chemical imaging offers a unique insight enabling the visualisation of the different constituents of a pharmaceutical tablet. It allows identifying ingredients poorly distributed offering the possibility to optimize the process parameters or to adapt characteristics of incoming raw materials to increase the final product quality. Among the available chemical imaging tools, Raman imaging is one of the most widely used since it offers a high spatial resolution with well-resolved peaks resulting in a high spectral specificity. However, Raman imaging suffers from sample autofluorescence and long acquisition times. Recently commercialised, laser direct infrared reflectance imaging (LDIR) is a quantum cascade laser (QCL) based imaging technique that offers the opportunity to rapidly analyse samples. In this study, a typical pharmaceutical formulation blend composed of two active pharmaceutical ingredients and three excipients was aliquoted at different mixing timepoints. The collected aliquots were tableted and analysed using both Raman and LDIR imaging. The distributional homogeneity indexes of one active ingredient image were then computed and compared. The results show that both techniques achieved similar conclusions. However, the analysis times were drastically different. While Raman imaging required a total analysis time of 4 h per tablet to obtain the distribution map of acetylsalicylic acid with a step size of 100 µm, it only took 7.5 min to achieve the same result with LDIR. The results obtained in the present study show that LDIR is a promising technique for the analysis of pharmaceutical formulations and that it could be a valuable tool when developing new pharmaceutical formulations.

Nowadays, many efforts are devoted to improve analytical methods regarding efficiency, analysis time and greenness. In this context, Supercritical Fluid Chromatography (SFC) is often regarded as a good alternative over Normal Phase Liquid Chromatography (NPLC). Indeed, modern SFC separations are fast, efficient with suitable quantitative performances. Moreover, the hyphenation of SFC to mass spectrometry (MS) provides additional gains in specificity and sensitivity. The present work aims at the determination of vitamin D3 by SFC-MS for routine Quality Control (QC) of medicines specifically. Based on the chromatographic parameters previously defined in SFC-UV by Design of Experiments (DoE) and Design Space methodology, the method was adapted to work under isopycnic conditions ensuring a baseline separation of the compounds. Afterwards, the response provided by the MS detector was optimized by means of DoE methodology associated to desirability functions. Using these optimal MS parameters, quantitative performances of the SFC-MS method were challenged by means of total error approach method validation. The resulting accuracy profile demonstrated the full validity of the SFC-MS method. It was indeed possible to meet the specification established by the European Medicines Agency (EMA) (i.e. 95.0 - 105.0% of the API content) for a dosing range corresponding to at least 70.0-130.0% of the API content. These results highlight the possibility to use SFC-MS for the QC of medicine and obviously support the switch to greener analytical methods.

In the uprising context of green analytical chemistry, Supercritical Fluid Chromatography (SFC) is often suggested as an alternative to Normal Phase Liquid Chromatography. Indeed, SFC provides fast, efficient and green separations. In this report, the quantitative performances of SFC were challenged on a real-life case study: the Quality Control (QC) of vitamin D3. A rapid and green SFC method was optimized thanks to the Design of Experiments-Design Space (DoE-DS) methodology. It provided robust and high quality separation of the compounds within a 2min timeframe, using a gradient of ethanol as co-solvent of the carbon dioxide. The analytical method was fully validated according to the total error approach, demonstrating the compliance of the method to the specifications of U.S. Pharmacopeia (USP: 97.0-103.0%) and European Pharmacopeia (EP: 97.0-102.0%) for an interval of [50-150%] of the target concentration. In order to allow quantification of impurities using vitamin D3 as an external standard in SFC-UV, correction factors were determined and verified during method validation. Thus, accurate quantification of impurities was demonstrated at the specified levels (0.1 and 1.0% of the main compound) for a 70.0-130.0% dosing range. This work demonstrates the validity of an SFC method for the QC of vitamin D3 raw material and its application to real samples. Therefore, it supports the switch to a greener and faster separative technique as an alternative to NPLC in the pharmaceutical industry.

Triple $\ensuremath{\beta}$ decay of $^{150}\mathrm{Nd}$ to the ground and excited states of $^{150}\mathrm{Eu}$ and quadruple $\ensuremath{\beta}$ decay of $^{150}\mathrm{Nd}$ to the excited states of $^{150}\mathrm{Gd}$ have been studied using a 400 ${\mathrm{cm}}^{3}$ low-background high-purity germanium detector and an external source consisting of 3046 g of natural ${\mathrm{Nd}}_{2}{\mathrm{O}}_{3}$ powder. A half-life limit for the quadruple $\ensuremath{\beta}$ decay to the ${0}_{1}^{+}$ state of $^{150}\mathrm{Gd}$ was found to be ${T}_{1/2}(0\ensuremath{\nu}+4\ensuremath{\nu})g8.7\ifmmode\times\else\texttimes\fi{}{10}^{20}$ yr (90% C.L.). For other ($0\ensuremath{\nu}+4\ensuremath{\nu}$) transitions to the ${2}_{1}^{+}$, ${3}_{1}^{\ensuremath{-}}$, ${4}_{1}^{+}$, ${2}_{2}^{+}$, and ${2}_{3}^{+}$ excited states limits have been obtained for the first time at the level of $(6.1--9.5)\ifmmode\times\else\texttimes\fi{}{10}^{20}$ yr (90% C.L.). We report here also the results for the first search for triple $\ensuremath{\beta}$ decay to the ground and excited final states of $^{150}\mathrm{Eu}$. We find no evidence of this decay and set lower limits on the half-life in the range ${T}_{1/2}(0\ensuremath{\nu}+3\ensuremath{\nu})g(0.04\ensuremath{-}4.8)\ifmmode\times\else\texttimes\fi{}{10}^{20}$ yr (90% C.L.).

Handheld Raman spectroscopy is actually booming. Recent devices improvements aim at addressing the usual Raman spectroscopy issues: fluorescence with shifted‐excitation Raman difference spectroscopy (SERDS), poor sensitivity with surface enhanced Raman scattering (SERS) and information only about the sample surface with spatially offset Raman spectroscopy (SORS). While qualitative performances of handheld devices are generally well established, the quantitative analysis of pharmaceutical samples remains challenging. The aim of this study was to compare the quantitative performances of three commercially available handheld Raman spectroscopy devices. Two of them (TruScan and IDRaman mini) are equipped with a 785 nm laser wavelength and operate in a conventional backscattering mode. The IDRaman has the Orbital Raster Scanning (ORS) option to increase the analyzed surface. The third device (Resolve) operates with an 830 nm laser wavelength both in backscattering and in SORS modes. The comparative study was carried out on ibuprofen-mannitol-microcrystalline cellulose ternary mixtures. The concentration of ibuprofen ranged from 24 to 52% (w/w) while the proportions of the two excipients were varied to avoid cross-correlation as much as possible. Analyses were performed either directly through a glass vial or with the glass vial in an opaque polypropylene flask, using a validated FT-NIR spectroscopy method as a reference method. Chemometric analyses were carried out with the Partial Least Squares Regression (PLS-R) algorithm. The quantitative models were validated using the total error approach and the ICH Q2 (R1) guidelines with ± 15% as acceptance limits.

Within the family of serotonin (5-HT) receptors, the 5-HT

The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $^{100}$Mo to the ground state of $^{100}$Ru, $T_{1/2} = \left[ 6.81 \pm 0.01\,\left(\mbox{stat}\right) ^{+0.38}_{-0.40}\,\left(\mbox{syst}\right) \right] \times10^{18}$ y. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $5\times10^5$ events and a signal-to-background ratio of ~80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of n=2,3,7, as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained., 11 pages, 9 figures

Plant root-knot nematode (RKN) interaction studies are performed on several host plant models. Though RKN interact with trees, no perennial woody model has been explored so far. Here, we show that poplar (Populus tremula × P. alba) grown in vitro is susceptible to Meloidogyne incognita, allowing this nematode to penetrate, to induce feeding sites, and to successfully complete its life cycle. Quantitative reverse transcription-polymerase chain reaction analysis was performed to study changes in poplar gene expression in galls compared with noninfected roots. Three genes (expansin A, histone 3.1, and asparagine synthase), selected as gall development marker genes, followed, during poplar-nematode interaction, a similar expression pattern to what was described for other plant hosts. Downregulation of four genes implicated in the monolignol biosynthesis pathway was evidenced in galls, suggesting a shift in the phenolic profile within galls developed on poplar roots. Raman microspectroscopy demonstrated that cell walls of giant cells were not lignified but mainly composed of pectin and cellulose. The data presented here suggest that RKN exercise conserved strategies to reproduce and to invade perennial plant species and that poplar is a suitable model host to study specific traits of tree-nematode interactions.

In this study, adipose-derived stem cells (ASCs) are used to produce 3D bone grafts. The safety and the feasibility of using these bone grafts have been already showed and quality controls are already implemented. However, a cheaper, fast and non-destructive technique is required to monitor the osteogenic differentiation process. Here, the use of Raman imaging to monitor the synthesis of the extracellular matrix and its progressive mineralization occurring during the osteogenic differentiation process is investigated for the first time on a 3D in forming bone tissue. The attention was focused on Raman bands related to this matrix belonging to phosphate, phenylalanine and hydroxyproline, which are very distinctive and intense. The kinetic of the osteogenic differentiation process was first compared between a 2D and a 3D forming bone tissue. It was observed that the kinetics of the osteogenic differentiation process is slower in 3D in forming bone tissue. In a second step, an evaluation of the reliability of the Raman imaging method was performed including a study of the influence of the harvest biopsies position on the forming 3D bone tissue. The repeatability and the specificity of this method were also demonstrated. In a last step, several batches of ASCs were cultured and analyzed in 3D at different time points using Raman imaging. From the mean Raman spectra, mineral to matrix ratios (MTMR) were determined and used to evaluate the formation of mineral deposits accompanying the extracellular matrix synthesis which is indicative of an ongoing osteogenic differentiation process. These ratios peaked between the day 35 and 49. This observation was very interesting since it corresponds to the time at which the 3D bone grafts are used for the patient surgery. To conclude, Raman imaging allowed fast acquisition and time-resolved monitoring in vitro of the mineralization of extracellular matrix during osteogenic differentiation.

Within the family of serotonin (5-HT) receptors, the 5-HT1A subtype is particularly interesting as it may be involved in various physiological processes or psychological disorders. The p-[18F]MPPF, a highly selective 5-HT1A antagonist, is used for in vivo studies in human or animal by means of positron emission tomography (PET) [1]. In order to selectively extract p-[18F]MPPF and its main metabolites from plasma, molecularly imprinted polymer (MIP) was prepared against these compounds by using the p-MPPF as template. For the control of the selectivity, non-imprinted polymer (NIP) was also synthesized without template. The MIP sorbent, packed in disposable extraction cartridges (DECs), was then evaluated as molecularly imprinted solid-phase extraction (MISPE) prior to the LC determination. The conditions of extraction were evaluated in order to obtain the highest selective retention of the p-[18F]MPPF and its metabolites on this MIP. The MIP selectivity was exploited in the loading and washing steps by adjusting the pH of plasma samples at a suitable value and by selecting mixtures for the washing step to limit the contribution of non-specific interactions. Other important parameters involved in the conditioning and elution steps were also studied. Finally, a pre-validation was carried out with optimal extraction conditions to demonstrate the performance of this MISPE-LC method as a generic method in the context of evaluation of new MISPE for p-[18F]MPPF and its potential for metabolites extraction from human plasma.

Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay ( $2\nu \beta \beta $ ) half-life of$^{82}$ Se as $T_{\smash {1/2}}^{2\nu } \!=\! \left[ 9.39 \pm 0.17\left( \text{ stat }\right) \pm 0.58\left( \text{ syst }\right) \right] \times 10^{19}$ y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is $\left| M^{2\nu }\right| = 0.0498 \pm 0.0016$ . In addition, a search for neutrinoless double beta decay ( $0\nu \beta \beta $ ) using 0.93 kg of$^{82}$ Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of $T_{1/2}^{0\nu } > 2.5 \times 10^{23} \,\text{ y } \,(90\%\,\text{ C.L. })$ for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of $\langle m_{\nu } \rangle < \left( 1.2{-}3.0\right) \,\text{ eV }$ , where the range reflects $0\nu \beta \beta $ nuclear matrix element values from different calculations. Furthermore, constraints on lepton number violating parameters for other $0\nu \beta \beta $ mechanisms, such as right-handed currents, majoron emission and R-parity violating supersymmetry modes have been set.

The analysis of serum samples by surface-enhanced Raman spectroscopy (SERS) has gained ground over the last years. However, the stabilisation of colloids by the proteins contained in these samples has restricted their use in common practice, unless antibodies or aptamers are used. Therefore, this work was dedicated to the development of a SERS methodology allowing the analysis of serum samples in a simple and easy-to-implement way. This approach was based on the pre-aggregation of the colloid with a salt solution. Gold nanoparticles (AuNPs) were used as the SERS substrate and, owing to its physiopathological importance, dopamine was chosen as a model to implement the SERS approach. The presence of this neurotransmitter could be determined in the concentration range 0.5 to 50 ppm (2.64 – 264 μM) in the culture medium of PC-12 cells, with a R2 of 0.9874, and even at lower concentrations (0.25 ppm, 1.32 μM) in another matrix containing fewer proteins. Moreover, the effect of calcium and potassium on the dopamine exocytosis from PC-12 cells was studied. Calcium was shown to have a predominant and dose-dependent effect. Finally, PC-12 cells were exposed to dexamethasone in order to increase their biosynthesis and release of dopamine. This increase was monitored with the developed SERS approach.

Terahertz spectroscopy and imaging have proved to be a versatile tool for the studying of drugs and pharmaceutical analysis. Particularly, this method has been employed to map the coating layer of pharmaceutical tablets, to identify the polymorphism of active pharmaceutical ingredients (APIs), etc. In this paper, Terahertz (THz) hyper-spectral imaging using time-domain spectroscopy technique has been applied to image a commercial packaging of paracetamol tablets, showing the ability to penetrate through both cardboard of the box and plastic cover of the blister pack. The advantage of THz time-domain spectroscopy (THz-TDS) is that not only the dimensional imaging was captured but also the spectral information was registered. A comparison between THz spectrum of commercial and lab-prepared paracetamol tablets shows the presence of a certain amount of α-D-lactose monohydrate at the absorption peak of 0.53 THz. Any API or excipients can be detected if their fingerprints fall in the measureable range of the system. This work opens up a possibility of using THz-TDS to non-destructively control the quality of pharmaceutical products while they are still in their packaging. This potential capacity is important as for the identification of the APIs as well as changing of unwanted physical (and hence biological) properties during the shelf-life of the product.

Since the last decade, more and more Active Pharmaceutical Ingredient (API) candidates have poor water solubility inducing low bioavailability. These molecules belong to the Biopharmaceutical Classification System (BCS) classes II and IV. Thanks to Hot-Melt Extrusion (HME), it is possible to incorporate these candidates in pharmaceutical solid forms. Indeed, HME increases the solubility and the bioavailability of these drugs by encompassing them in a polymeric carrier and by forming solid dispersions. Moreover, in 2004, the FDA's guidance initiative promoted the usefulness of Process Analytical Technology (PAT) tools when developing a manufacturing process. Indeed, the main objective when developing a new pharmaceutical process is the product quality throughout the production chain. The trend is to follow this parameter in real-time in order to react immediately when there is a bias. Vibrational spectroscopic techniques, NIR and Raman, are useful to analyze processes in-line. Moreover, off-line Raman microspectroscopy is more and more used when developing new pharmaceutical processes or when analyzing optimized ones by combining the advantages of Raman spectroscopy and imaging. It is an interesting tool for homogeneity and spatial distribution studies. This review treats about spectroscopic techniques analyzing a HME process, as well off-line as in-line, presenting their advantages and their complementarities.

To control the authenticity of an old wine without opening the bottle, we developed a few years ago a method based on the measurement of the 137 Cs activity. However, for recent vintages, the 137 Cs activity drops to far too low values (most of the time less than 10 mBq/L for a 10-year-old wine) for this method to perform correctly. In this paper we examine the possibility to date wines using the natural radio-element 210 Pb which has a 22-year period. This new method we propose implies the opening of the bottle and the follow-on destruction of the wine itself, which means that it can only be used for investigating non-expensive bottles or wine lots where there are multiple bottles of the same provenance. Uncertainties on the resulting 210 Pb radioactivity values are large, up to more than 50%, mainly due to local atmospheric variations, which prevents us to carry out precise dating. However it can be used to discriminate between an old wine (pre-1952) and a young wine (past-1990), an information that cannot be obtained with the other techniques based on other isotopes ( 137 Cs, 14 C or tritium).

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-β decay of Nd150 using a total exposure of 0.19 kg yr recorded with the NEMO-3 detector at the Modane Underground Laboratory. We find no evidence of this decay and set lower limits on the half-life in the range T1/2>(1.1–3.2)×1021 yr at the 90% C.L., depending on the model used for the kinematic distributions of the emitted electrons.

Surface-enhanced Raman spectroscopy (SERS) is a sensitive analytical tool used in the pharmaceutical field in recent years. SERS keeps all the advantages of classical Raman spectroscopy while being is more sensitive allowing its use for the detection and the quantification of low-dose substances contained in pharmaceutical samples. However, the analytical performance of SERS is limited due to the difficulty to implement a quantitative methodology correctly validated. Nevertheless, some studies reported the development of SERS quantitative methods especially in pharmaceutical approaches. In this context, this review presents the main concepts of the SERS technique. The different steps that need to be applied to develop a SERS quantitative method are also deeply described. The last part of the present manuscript gives a critical overview of the different SERS pharmaceutical applications that were developed for a non-exhaustive list of pharmaceutical compounds with the aim to highlights the validation criteria for each application.

The development of a quantitative method determining the crystalline percentage in an amorphous solid dispersion is of great interest in the pharmaceutical field. Indeed, the crystalline Active Pharmaceutical Ingredient transformation into its amorphous state is increasingly used as it enhances the solubility and bioavailability of Biopharmaceutical Classification System class II drugs. One way to produce amorphous solid dispersions is the Hot-Melt Extrusion (HME) process. This study reported the development and the comparison of the analytical performances of two techniques, based on backscattering and transmission Raman spectroscopy, determining the crystalline remaining content in amorphous solid dispersions produced by HME. Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression were performed on preprocessed data and tended towards the same conclusions: for the backscattering Raman results, the use of the DuoScan™ mode improved the PCA and PLS results, due to a larger analyzed sampling volume. For the transmission Raman results, the determination of low crystalline percentages was possible and the best regression model was obtained using this technique. Indeed, the latter acquired spectra through the whole sample volume, in contrast with the previous surface analyses performed using the backscattering mode. This study consequently highlighted the importance of the analyzed sampling volume.

Since the Food and Drug Administration (FDA) published a guidance based on the Process Analytical Technology (PAT) approach, real-time analyses during manufacturing processes are in real expansion. In this study, in-line Raman spectroscopic analyses were performed during a Hot-Melt Extrusion (HME) process to determine the Active Pharmaceutical Ingredient (API) content in real-time. The method was validated based on a univariate and a multivariate approach and the analytical performances of the obtained models were compared. Moreover, on one hand, in-line data were correlated with the real API concentration present in the sample quantified by a previously validated off-line confocal Raman microspectroscopic method. On the other hand, in-line data were also treated in function of the concentration based on the weighing of the components in the prepared mixture. The importance of developing quantitative methods based on the use of a reference method was thus highlighted. The method was validated according to the total error approach fixing the acceptance limits at ±15% and the α risk at ±5%. This method reaches the requirements of the European Pharmacopeia norms for the uniformity of content of single-dose preparations. The validation proves that future results will be in the acceptance limits with a previously defined probability. Finally, the in-line validated method was compared with the off-line one to demonstrate its ability to be used in routine analyses.

The poor quality of medicines is a crucial problem of public health. Therefore, it is important to have analytical tools to attend decisions of the legal authorities while combating this offense. In this context, the main objective of this study was to develop generic methods able to trace, screen and determine several antibiotics and common associated molecules by mean of liquid chromatographic techniques. For that purpose, an innovative Design Space optimization strategy was applied, targeting 16 antibiotics and 3 beta-lactamase inhibitors. The robustness of the developed method allowed using its use in an environment where operational factors such as temperature are not easy to control and eased its transfer to Ultra High Performance Liquid Chromatography. To demonstrate its ability to quantify the targeted molecules, the developed and transferred method was fully validated for two active ingredients commonly used in association, sulbactam and ceftriaxone, using the accuracy profile as decision tool. Based on this successful step, the method was then used for the quantitative determination of these two active ingredients in three pharmaceutical brands marketed in the Democratic Republic of Congo. Two out of the three pharmaceutical products did not comply with the specifications.

Lead-210 is unknown to the general public, but one of its daughters, polonium-210, made newspaper headlines several times in 2006 and 2012. In 2006 the whole world learned that a former Russian KGB agent named Alexander Litvinenko had been poisoned by polonium-210, a powerful short-lived alpha emitter. The ingested poisoning activity was estimated to be more than 1–3 GBq [1], which is ~6 μg of pure 210Po. The experts agree that it is an ideal weapon, impossible to detect with the naked eye and that a lethal dose can be held in a volume the size of a homeopathic pill. In 2012 we learned that traces of 210Po were found on the underwear, hat, and toothbrush of Yasser Arafat, the Palestinian leader who died in 2004. Calculation of the activity at the time of his death shows that poisoning with 210Po is not excluded. The different samples collected during the exhumation will probably answer the question.

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.

Following the Fukushima nuclear accident, low-background gamma spectrometry measurements were performed with HPGe detectors at the PRISNA platform located at the CENBG laboratory in Bordeaux, France. Different kinds of samples were collected and measured between March 26 and May 14, 2011. The first fission product observed was (131)I with maximum activity values of 2.4 mBq/m(3) in atmospheric dusts in air, 3.5 Bq/L in rain water, 15 Bq/kg in grass and 0.9 Bq/L in cow milk. The (134,137)Cs isotopes were also detected in air and in grass at a maximum level of 0.2 mBq/m(3) and 0.7 Bq/kg respectively, around one order of magnitude less than (131)I activity, but they were below detection limits in the other samples. All these activity values were consistent with others measured in France by IRSN and were well below those reported in May 1986 after the Chernobyl accident.

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.

A new application of surface-enhanced Raman scattering (SERS) in the field of plant material analysis is proposed in this study. The aim was to monitor the release of anatabine by methyl jasmonate (MeJa) elicited Bright Yellow-2 (BY-2) cells. Gold nanoparticles (AuNps) were used as SERS substrate. The first step was to study the SERS activity of anatabine in a complex matrix comprising the culture medium and BY-2 cells. The second step was the calibration. This one was successfully performed directly in the culture medium in order to take into account the matrix effect, by spiking the medium with different concentrations of anatabine, leading to solutions ranging from 250 to 5000 µg L−1. A univariate analysis was performed, the intensity of a band situated at 1028 cm−1, related to anatabine, was plotted against the anatabine concentration. A linear relationship was observed with a R2 of 0.9951. During the monitoring study, after the MeJa elicitation, samples were collected from the culture medium containing BY-2 cells at 0, 24 h, 48 h, 72 h and 96 h and were analysed using SERS. Finally, the amount of anatabine released in the culture medium was determined using the response function, reaching a plateau after 72 h of 82 µg of anatabine released/g of fresh weight (FW) MeJa elicited BY-2 cells.

The NEMO-3 experiment at the Modane Underground Laboratory has investigated the double-$\beta$ decay of $^{48}{\rm Ca}$. Using $5.25$ yr of data recorded with a $6.99\,{\rm g}$ sample of $^{48}{\rm Ca}$, approximately $150$ double-$\beta$ decay candidate events have been selected with a signal-to-background ratio greater than $3$. The half-life for the two-neutrino double-$\beta$ decay of $^{48}{\rm Ca}$ has been measured to be $T^{2\nu}_{1/2}\,=\,[6.4\, ^{+0.7}_{-0.6}{\rm (stat.)} \, ^{+1.2}_{-0.9}{\rm (syst.)}] \times 10^{19}\,{\rm yr}$. A search for neutrinoless double-$\beta$ decay of $^{48}{\rm Ca}$ yields a null result and a corresponding lower limit on the half-life is found to be $T^{0\nu}_{1/2} > 2.0 \times 10^{22}\,{\rm yr}$ at $90\%$ confidence level, translating into an upper limit on the effective Majorana neutrino mass of $ < 6.0 - 26$ ${\rm eV}$, with the range reflecting different nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right-handed currents.

An innovative versatile strategy using Total Error has been proposed to decide about the method's validity that controls the risk of accepting an unsuitable assay together with the ability to predict the reliability of future results. This strategy is based on the simultaneous combination of systematic (bias) and random (imprecision) error of analytical methods. Using validation standards, both types of error are combined through the use of a prediction interval or β-expectation tolerance interval. Finally, an accuracy profile is built by connecting, on one hand all the upper tolerance limits, and on the other hand all the lower tolerance limits. This profile combined with pre-specified acceptance limits allows the evaluation of the validity of any quantitative analytical method and thus their fitness for their intended purpose. In this work, the approach of accuracy profile was evaluated on several types of analytical methods encountered in the pharmaceutical industrial field and also covering different pharmaceutical matrices. The four studied examples depicted the flexibility and applicability of this approach for different matrices ranging from tablets to syrups, different techniques such as liquid chromatography, or UV spectrophotometry, and for different categories of assays commonly encountered in the pharmaceutical industry i.e. content assays, dissolution assays, and quantitative impurity assays. The accuracy profile approach assesses the fitness of purpose of these methods for their future routine application. It also allows the selection of the most suitable calibration curve, the adequate evaluation of a potential matrix effect and propose efficient solution and the correct definition of the limits of quantification of the studied analytical procedures. Copyright © 2012 John Wiley & Sons, Ltd.

Analytical methods capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices have to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work, an improved capability index, namely Cpk-tol and the corresponding estimator of proportion of non-conforming results (π(Cpk-tol)) have been proposed. Through Monte-Carlo simulations, they have been shown to greatly increase the estimation of analytical methods capability in particular in low sample size situations as encountered during methods validation or transfer. Additionally, the usefulness of this capability index has been illustrated through several case studies covering applications commonly encountered in the pharmaceutical industry. Finally a methodology to determine the optimal sample size required to validate analytical methods is also given using the proposed capability metric.

When developing a new formulation, the development, calibration and validation steps of analytical methods based on vibrational spectroscopy are time-consuming. For each new formulation, real samples must be produced and a "reference method" must be used in order to determine the Active Pharmaceutical Ingredient (API) content of each sample. To circumvent this issue, the paper presents a simple approach based on the film-casting technique used as a calibration tool in the framework of hot-melt extrusion process. Confocal Raman microscopic method was successfully validated for the determination of itraconazole content in film-casting samples. Then, hot-melt extrusion was carried out to produce real samples in order to confront the results obtained with confocal Raman microscopy and Ultra High Performance Liquid Chromatography (UHPLC). The agreement between both methods was demonstrated using a comparison study based on the Bland and Altman's plot.

African populations use traditional medicines in their initial attempt to treat a range of diseases. Nevertheless, accurate knowledge of the composition of these drugs remains a challenge in terms of ensuring the health of population and in order to advance towards improved traditional medicines (ITMs). In this paper chromatographic methods were developed for qualitative and quantitative analyses of a per os antimalarial ITM containing Garcinia kola. The identified analytical markers were used to establish TLC and HPLC fingerprints. G. kola seeds were analysed by HPLC to confirm the identity of the extract used by the Congolese manufacturer in the ITM. The main compounds (GB1, GB2, GB-1a and Kolaflavanone) were isolated by preparative TLC and identified by UPLC–MS and NMR. For the quantification of the major compound GB1, a simple and rapid experimental design was applied to develop an LC method, and then its validation was demonstrated using the total error strategy with the accuracy profile as a decision tool. The accurate results were observed within 0.14–0.45 mg/mL range of GB1 expressed as naringenin. The extracts used in several batches of the analysed oral solutions contained GB1 (expressed as naringenin) within 2.04–2.43%. Both the fingerprints and the validated LC-DAD were found suitable for the quality control of G. kola -based raw material and finished products, respectively.

Bioanalytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will be made with them. Even if several guidelines exist to help perform bioanalytical method validations, there is still the need to clarify the meaning and interpretation of bioanalytical method validation criteria and methodology. Yet, different interpretations can be made of the validation guidelines as well as for the definitions of the validation criteria. This will lead to diverse experimental designs implemented to try fulfilling these criteria. Finally, different decision methodologies can also be interpreted from these guidelines. Therefore, the risk that a validated bioanalytical method may be unfit for its future purpose will depend on analysts personal interpretation of these guidelines. The objective of this review is thus to discuss and highlight several essential aspects of methods validation, not only restricted to chromatographic ones but also to ligand binding assays owing to their increasing role in biopharmaceutical industries. The points that will be reviewed are the common validation criteria, which are selectivity, standard curve, trueness, precision, accuracy, limits of quantification and range, dilutional integrity and analyte stability. Definitions, methodology, experimental design and decision criteria are reviewed. Two other points closely connected to method validation are also examined: incurred sample reproducibility testing and measurement uncertainty as they are highly linked to bioanalytical results reliability. Their additional implementation is foreseen to strongly reduce the risk of having validated a bioanalytical method unfit for its purpose.

The proportion of counterfeit medicines is dramatically increasing these last few years. According to numerous official sources, in some pharmaceutical wholesalers in African countries, the proportion has reached 80%. Unfortunately, this situation is far to be improved due to lack of suitable analytical equipment allowing rapid actions of the Regulatory Agencies based on scientific consideration, at affordable cost and all over the drug supply chain. For that purpose, a network group considered that mater by building a low-cost original capillary electrophoresis (CE) equipment equipped with a new deep UV detector based on LED technology. The generic conditions for analysis were investigated: capillary zone electrophoresis (CZE) performed at acidic pH for basic drug molecules (i.e., quinine, highly used as the last antimalarial rampart), basic pH for compounds such as furosemide (a common diuretic drug) and at neutral pH for a well known antibiotic combination, trimethoprim/sulfamethoxazol. To evaluate the ability of the CE equipment for quantification, a full validation and a method comparison study were carried out for the CZE method dedicated to quinine determination. The validation involved the use of accuracy profile and total error concept to monitor the adequacy of the results obtained by the new prototype. The method comparison was based on the Bland and Altman approach by comparing results obtained by the low-cost CE and a conventional set-up. Subsequent validation studies were realized with neutral and acidic drug molecules, each focusing on a single concentration level calibration curve in order to maintain as low as possible the expenses due to reagents and thus the cost of analysis, as important advantages of CE for drug quality control.

A sensitive and accurate LC/MS method was developed for the monitoring of glucosamine (GLcN) dog plasmatic concentration. In this scope, relatively low plasmatic concentrations of GLcN were expected, ranging from 50 to 1000 ng/mL. Liquid chromatography coupled to simple quadrupole mass spectrometry detection (LC/MS) was selected bringing the selectivity and the sensitivity needed for this application. Additionally, a solid phase extraction (SPE) step was performed to reduce matrix and ion suppression effects. Due to the ionisable character of the compound of interest, a mixed-mode strong cation exchange (Plexa PCX) disposable extraction cartridge (DEC) was selected. The separation was carried out on a Zorbax SB-CN column (5 microm, 4.6mm i.d. x 250 mm), considering hydrophilic interaction liquid chromatography (HILIC). Indeed, the mobile phase was made of methanol and 5mM ammonium hydrogen carbonate buffer at pH 7.5 (95/5, v/v). The detection was led at m/z ratios of 180.0 and 417.0, for GLcN and IS, respectively. Reliability of the results was demonstrated through the validation of the method using an approach based on the accuracy profile allowing managing the risk associated to the use of these methods in routine analysis: it is thus guaranteed that each future result will fall in the +/-30% acceptance limits with a probability of at least 90%. Successful application of the method to a preliminary pharmacokinetic study illustrated the usefulness of the method for pre-clinical studies.

Tin octoate is used as a catalyst in the synthesis of polydimethylsiloxane (PDMS), a room temperature vulcanizing (RTV) silicone rubber. This rubber is largely used in the medical field due to its great biocompatibility. In this framework, a high-speed and costless analytical method for the determination of stannic ions, Sn(IV), in the presence of stannous ions, Sn(II), has been developed. The separation of these two ions was carried out using differential pulse polarography (DPP). For this purpose, the tin species contents in the catalyst is quantitatively extracted under inert condition to avoid any changes in the ratio Sn(IV)/Sn(II). Polarography showed well-shaped oxidation and reduction peaks respectively at -650 and -860mV for stannous ions. The peak of the stannic ion was well separated and appeared at -1210mV. Many parameters such as extraction process, extraction time, pH, chelating agents and polarographic conditions were optimized. We have also demonstrated that no oxidation of the stannous ions occurred during the sample preparation. The dosing range considered in this study extends between 10 and 40mug/mL, corresponding to 6.8% and 27.2% of the degradation product (Sn(IV)) in the catalyst, regarding to the sampling. Finally this method was successfully validated using the total error concept.

The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of heterosides and asiatic acid for aglycones. The evaluation of the extraction efficiency of the four molecules led to use Soxhlet extraction for 8 h. The method was validated and was found to be accurate in the concentration range of 1.0-3.0 mg/ml for asiaticoside and 0.5-2.0 mg/ml for asiatic acid with CV

Limits on β + EC and ECEC processes in 112Sn and on β − β − decay of 124Sn to the excited states of 124Te have been obtained using a 380 cm3 HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the 112Sn half-life of 0.92 × 10 20 y for the ECEC(0ν) transition to the 0 3 + excited state in 112Cd (1871.0 keV) has been established. This transition is discussed in the context of a possible enhancement of the decay rate by several orders of magnitude given that the ECEC(0ν) process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such a process in future experiments are discussed. The β − β − decay limits for 124Sn to the excited states of 124Te were obtained on the level of (0.8–1.2) × 1021 y at the 90% C.L.

The monitoring in real time of dynamic extractions of tagitinin C from Tithonia diversifolia leaves was carried out with a home made high-pressure fiber optic cell which coupled a supercritical fluid extractor with carbon dioxide as the extraction medium and a FT-IR spectrometer equipped with a mercury cadmium telluride detector (MCT). The shape of extraction curves obtained during the monitoring was used to decide when to stop the supercritical fluid extraction (SFE). No significant density dependence of the molar absorption coefficient or wavenumber of the C O stretching vibration (ν C O ) of tagitinin C at 1668 cm −1 was noticed. The physical characteristics of SCCO 2 governing the extraction yield of the active component from leaves were optimized by means of a central composite design (CCD). The studied variables were temperature (40, 60 and 80 °C) and pressure (8.0, 14.0 and 20.0 MPa) of the supercritical fluid. The composition profile of T. diversifolia extracts obtained by SFE was investigated in the range from 3400 to 2600 cm −1 according to the pressure and temperature conditions of SCCO 2 . The qualitative approach of the extracts composition was accomplished through the CH stretching vibrations ( ν CH ) of components.

Supercritical fluid extraction (SFE) with carbon dioxide as extraction medium was on-line coupled to a FT-IR spectrometer equipped with a Mercury Cadmium Telluride (MCT) detector using a tailor-made high-pressure fibre optic flow cell. This method was optimised and developed for the monitoring in real time and the quantification of dynamic extractions of tagitinin C from Tithonia diversifolia leaves. In order to demonstrate the method ability to allow the direct quantification of tagitinin C in the extract medium the standard addition method was used. The area integration of curves obtained by plotting the absorbance of the highly specific C O stretching vibration at 1668 cm −1 versus time (i.e. extractograms) was used as instrumental response. The SFE/FT-IR process was successfully validated using the accuracy profile as decision tool. On this basis, a linear regression model was chosen for the calibration curve. The relative standard deviation for repeatability and intermediate precision were between 0.8 and 3.1 %, respectively. Moreover, the method was found to be accurate as the two-sided 95% beta-expectation tolerance interval did not exceed the acceptance limits of 85 and 115% on the analytical range investigated (500–2500 μg of added amount of tagitinin C). The proposed method allowed the non-destructive extraction of tagitinin C and its on-line quantitative determination in less than 25 min thus facilitating the subsequent experiments or the pharmacological studies performed on this compound.

The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double $\beta$ ($0\nu\beta\beta$) decay. We report final results of a search for $0\nu\beta\beta$ decays with $6.914$ kg of $^{100}$Mo using the entire NEMO-3 data set with a detector live time of $4.96$ yr, which corresponds to an exposure of 34.3 kg$\cdot$yr. We perform a detailed study of the expected background in the $0\nu\beta\beta$ signal region and find no evidence of $0\nu\beta\beta$ decays in the data. The level of observed background in the $0\nu\beta\beta$ signal region $[2.8-3.2]$ MeV is $0.44 \pm 0.13$ counts/yr/kg, and no events are observed in the interval $[3.2-10]$ MeV. We therefore derive a lower limit on the half-life of $0\nu\beta\beta$ decays in $^{100}$Mo of $T_{1/2}(0\nu\beta\beta)> 1.1 \times 10^{24}$ yr at the $90\%$ Confidence Level, under the hypothesis of light Majorana neutrino exchange. Depending on the model used for calculating nuclear matrix elements, the limit for the effective Majorana neutrino mass lies in the range $\langle m_{\nu} \rangle < 0.33$--$0.62$ eV. We also report constraints on other lepton-number violating mechanisms for $0\nu\beta\beta$ decays.

Bisphenol A (BPA) is well known for its use in plastic manufacture and thermal paper production despite its risk of health toxicity as an endocrine disruptor in humans. Since the publication of new legislation regarding the use of BPA, manufacturers have begun to replace BPA with other phenolic molecules such as bisphenol F (BPF) and bisphenol B (BPB), but there are no guarantees regarding the health safety of these compounds at this time. In this context, a very simple, cheap and fast surface-enhanced Raman scattering (SERS) method was developed for the sensitive detection of these molecules in spiked tap water solutions. Silver nanoparticles were used as SERS substrates. An original strategy was employed to circumvent the issue of the affinity of bisphenols for metallic surfaces and the silver nanoparticles surface was functionalized using pyridine in order to improve again the sensitivity of the detection. Semi-quantitative detections were performed in tap water solutions at a concentrations range from 0.25 to 20 μg L(-1) for BPA and BPB and from 5 to 100 μg L(-1) for BPF. Moreover, a feasibility study for performing a multiplex-SERS detection of these molecules was also performed before successfully implementing the developed SERS method on real samples.

Poor quality antimalarial drugs are one of the public's major health problems in Africa. The depth of this problem may be explained in part by the lack of effective enforcement and the lack of efficient local drug analysis laboratories. To tackle part of this issue, two spectroscopic methods with the ability to detect and to quantify quinine dihydrochloride in children's oral drops formulations were developed and validated. Raman and near infrared (NIR) spectroscopy were selected for the drug analysis due to their low cost, non-destructive and rapid characteristics. Both of the methods developed were successfully validated using the total error approach in the range of 50–150% of the target concentration (20% W/V) within the 10% acceptance limits. Samples collected on the Congolese pharmaceutical market were analyzed by both techniques to detect potentially substandard drugs. After a comparison of the analytical performance of both methods, it has been decided to implement the method based on NIR spectroscopy to perform the routine analysis of quinine oral drop samples in the Quality Control Laboratory of Drugs at the University of Kinshasa (DRC).

A collaborative study applying an enantiomeric liquid chromatographic (LC) method was carried out to determine the content of the enantiomeric impurity R -timolol and other related substances in three different S -timolol maleate samples. Eight laboratories, all located in Europe, participated in the study. The quantitative results obtained were used to estimate the uncertainty on the content of the different impurities. For that purpose, a set-up was adapted from the ISO guidelines 5725-2, which allowed the estimation of the different variances, i.e. the between-laboratories ( s laboratories 2 ), the between-days ( s days 2 ) and the between-replicates ( s replicates 2 ). The variances of repeatability ( s r 2 ) and reproducibility ( s R 2 ) were then calculated using the equations s r 2 = s replicates 2 and s R 2 = s replicates 2 + s days 2 + s laboratories 2 . For the timolol impurities, it was found that the estimated uncertainty seem to be concentration-dependent. Since the LC method which combines the compendial ones for enantiomeric purity and related substances testing was applied to evaluate uncertainty in this collaborative study, it was shown how a laboratory can evaluate the uncertainty of its results when applying the method in the future.