Application of Green Chiral Chromatography in Enantioseparation of Newly Synthesized Racemic Marinoepoxides.

Enantioseparation of the newly synthesized series of novel quinoline-2(1H)-one epoxide structures rac-6a-c and rac-8a-c, named marinoepoxides, is described. Marinoepoxide rac-6a, the key intermediate in the total synthesis of natural products marinoaziridines A and B, as well as their structural analogues, was synthesized by addition of the achiral ylide generated in situ from the sulfonium salt 5 or 7, to the carbon-oxygen double bond of the corresponding quinoline-2(1H)-one-4-carbaldehyde 4a-c in good yield. Separation of enantiomers of (±)-2,3,3-trisubstituted marinoepoxides rac-6a-c and (±)-trans-2,3-disubstituted marinoepoxides rac-8a-c was studied using two immobilized polysaccharide type chiral stationary phases (CSPs); tris-(3,5-dichlorophenylcarbamoyl)cellulose stationary phase (CHIRAL ART Cellulose-SC) and tris-(3,5-dimethylphenylcarbamoyl)amylose stationary phase (CHIRAL ART Amylose-SA). Enantioseparation conditions were explored by high-performance liquid chromatography (HPLC) using dimethyl carbonate/alcohol mixtures and n-hexane/ethanol (80/20, v/v) as mobile phase, and by supercritical fluid chromatography (SFC) using CO2/alcohol mixtures as mobile phase. In all examined racemates, enantioseparation was successfully achieved, but its efficiency largely depended on the structure of chiral selector and type/composition of the mobile phase.

Risk assessment for nitrosated pharmaceuticals: A future perspective in drug development.

Since June 2018, thousands of drug products from around the world had to be recalled due to the unexpected presence of nitrosamines (NAs). Starting with the pharmaceutical group of sartans, antidiabetic drugs, antihistamines, and antibiotics also became the subject of investigation. The occurrence of NAs has shown that pharmaceutical companies and regulatory agencies did not focus on these substances in the past during drug development. In this study, we incorporated a nitrosation assay procedure into high-resolution supercritical fluid chromatography (SFC)-mass spectrometry screening to test the potential of direct nitrosation of active pharmaceutical ingredients (APIs). The forced degradation study was performed with a four-fold molar excess of sodium nitrite, relative to the drug substance, at pH 3-4 for 4 h at 37°C. Chromatographic separation was performed on a porous graphitic carbon column by SFC. The mass analysis then focused on direct N-nitrosation or N-nitroso compounds (NOCs) formed after dealkylation. Substances (n = 67) from various pharmaceutical classes were evaluated and 49.3% of them formed NOCs, of which 21.2% have not yet been reported in the literature. In addition, for two APIs, which are known to form an unidentified NOC, the structure could be identified. A few substances also showed multiple NOCs and even N,N'-dinitroso-species. As NAs are carcinogens, they have to be eliminated or at least limited to prevent cancer in patients, who rely on these drugs. This study contributes a procedure that can be implemented in preapproval drug development and postapproval risk assessment to prevent unexpected findings in the future.

Combination of different chromatographic and sampling modes for high-resolution mass spectrometric screening of organic microcontaminants in water.

This study explores the combination of two sampling strategies (polar organic compounds integrative sampler (POCIS) vs. spot sampling) and four chromatographic retention modes (reversed-phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), mixed-mode liquid chromatography (MMLC) and supercritical fluid chromatography (SFC)) for high-resolution mass spectrometry (HRMS) screening of organic pollutants in water samples. To this end, a suspect screening approach, using iterative data-dependent tandem mass spectrometry (MS/MS) driven by a library of 3227 chemicals (including pharmaceuticals, pesticides, drugs of abuse, human metabolites, industrial chemicals and other pollutants), was employed. Results show that POCIS can afford a larger number of positive identifications as compared to spot sampling. On the other hand, the best suited retention mechanisms, in terms of identified analytes, are SFC, and followed by RPLC, MMLC and HILIC. However, the best combination (POCIS + SFC) would only allow the identification of 67% of the detected analytes. Thus, the combination of the two sampling strategies, spot and passive sampling, with two orthogonal retention mechanisms, RPLC and SFC, is proposed in order to maximize the number of analytes detected (89%). This strategy was applied to different surface water (river and estuary) samples from Galicia (NW Spain). A total of 155 compounds were detected at a confidence level 2a, from which the major class was pharmaceuticals (61%).

The Way to Ultrafast, High-Throughput Enantioseparations of Bioactive Compounds in Liquid and Supercritical Fluid Chromatography.

Until less than 10 years ago, chiral separations were carried out with columns packed with 5 or 3 µ m fully porous particles (FPPs). Times to resolve enantiomeric mixtures were easily larger than 30 min, or so. Pushed especially by stringent requirements from medicinal and pharmaceutical industries, during the last years the field of chiral separations by liquid chromatography has undergone what can be defined a "true revolution". With the purpose of developing ever faster and efficient method of separations, indeed, very efficient particle formats, such as superficially porous particles (SPPs) or.

Design and synthesis of molecular probes for the determination of the target of the anthelmintic drug praziquantel.

Schistosomiasis is a highly prevalent neglected tropical disease caused by blood-dwelling helminths of the genus Schistosoma. Praziquantel (PZQ) is the only drug available widely for the treatment of this disease and is administered in racemic form, even though only the (R)-isomer has significant anthelmintic activity. Progress towards the development of a second generation of anthelmintics is hampered by a lack of understanding of the mechanism of action of PZQ. In this Letter, we report an efficient protocol for the small-scale separation of enantiomers of 2 (hydrolyzed PZQ) using supercritical fluid chromatography (SFC). The enantiopure 2 was then used to develop several molecular probes, which can potentially be used to help identify the protein target of PZQ and study its mode of action.

[Determination of fatty acid composition after saponification of common oil pharmaceutical excipients by supercritical fluid-evaporative light scattering method and its application in oil identification].

Oils and fats are commonly used in the pharmaceutical industry as solvents, emulsifiers, wetting agents, and dispersants, and are an important category of pharmaceutical excipients. Fatty acids with unique compositions are important components of oil pharmaceutical excipients. The Chinese Pharmacopoeia provides clear descriptions of the fatty acid types and limits suitable for individual oil pharmaceutical excipient. An unqualified fatty acid composition or content may indicate adulteration or deterioration. The fatty acid composition, as a key indicator for the identification and adulteration evaluation of oil pharmaceutical excipients, can directly affect the quality and safety of oil pharmaceutical excipients and preparations. Gas chromatography is the most widely used technique for fatty acid analysis, but it generally requires derivatization, which affects quantitative accuracy. Supercritical fluid chromatography (SFC), an environmentally friendly technique with excellent separation capability, offers an efficient method for detecting fatty acids without derivatization. Unlike other chromatographic methods, SFC does not use nonvolatile solvents (e. g., water) as the mobile phase, rendering it compatible with an evaporative light-scattering detector (ELSD) for enhanced detection sensitivity. However, the fatty acids in oil pharmaceutical excipients exist in the free and bound forms, and the low content of free fatty acids in these oil pharmaceutical excipients not only poses challenges for their detection but also complicates the determination of characteristic fatty acid compositions and contents. Moreover, the compositions and ratios of fatty acids are influenced by environmental factors, leading to interconversion between their two forms. In this context, saponification provides a simpler and faster alternative to derivatization. Saponification degrades oils and fats by utilizing the reaction between esters and an alkaline solution, ultimately releasing the corresponding fatty acids. Because this method is more cost effective than derivatization, it is a suitable pretreatment method for the detection of fatty acids in oil pharmaceutical excipients using the SFC-ELSD approach. In this study, we employed SFC-ELSD to simultaneously determine six fatty acids, namely, myristic acid, palmitic acid, stearic acid, arachidic acid, docosanoic acid, and lignoceric acid, in oil pharmaceutical excipients. Saponification of the oil pharmaceutical excipients using sodium hydroxide methanol solution effectively avoided the bias in the determination of fatty acid species and contents caused by the interconversion of fatty acids and esters. The separation of the six fatty acids was achieved within 12 min, with good linearity within their respective mass concentration ranges. The limits of detection and quantification were 5-10 mg/L and 10-25 mg/L, respectively, and the spiked recoveries were 80.93%-111.66%. The method proved to be sensitive, reproducible, and stable, adequately meeting requirements for the analysis of fatty acids in oil pharmaceutical excipients. Finally, the analytical method was successfully applied to the determination of six fatty acids in five types of oil pharmaceutical excipients, namely, corn oil, soybean oil, coconut oil, olive oil, and peanut oil. It can be combined with principal component analysis to accurately differentiate different types of oil pharmaceutical excipients, providing technical support for the rapid identification and quality control of oil pharmaceutical excipients. Thus, the proposed method may potentially be applied to the analysis of complex systems adulterated with oil pharmaceutical excipients.

[Development progress of stationary phase for supercritical fluid chromatography and related application in natural products].

Supercritical fluid chromatography (SFC) is an environment-friendly and efficient column chromatography technology that was developed to expand the application range of high performance liquid chromatography (HPLC) using a supercritical fluid as the mobile phase. A supercritical fluid has a temperature and pressure that are above the critical values as well as relatively dynamic characteristics that are between those of a gas and liquid. Supercritical fluids combine the advantages of high solubility and diffusion, as their diffusion and viscosity coefficients are equivalent to those of a gas, while maintaining a density that is comparable with that of a liquid. Owing to the remarkable compressibility of supercritical fluids, analyte retention in SFC is significantly influenced by the density of the mobile phase. Thus, the column temperature and back pressure are crucial variables that regulate analyte retention in SFC. Increasing the back pressure can increase the density and solubility of the mobile phase, leading to reductions in retention time. The column temperature can affect selectivity and retention, and the degree to which different analytes are affected by this property varies. On the one hand, increasing the temperature reduces the density of the mobile phase, thereby extending the retention time of the analytes; on the other hand, it can also increase the energy of molecules, leading to a shorter retention time of the analyte on the stationary phase. CO2, the most widely employed supercritical fluid to date, presents moderate critical conditions and, more importantly, is miscible with a variety of polar organic solvents, including small quantities of water. In comparison with the mobile phases used in normal-phase liquid chromatography (NPLC) and reversed-phase liquid chromatography (RPLC), the mobile phase for SFC has a polarity that can be extended over a wide range on account of its extensive miscibility. The compatibility of the mobile phase determines the diversity of the stationary phase. Nearly all stationary phases for HPLC, including the nonpolar stationary phases commonly used for RPLC and the polar stationary phases commonly used for NPLC, can be applied to SFC. Because all stationary phases can use the same mobile-phase composition, chromatographic columns with completely different polarities can be employed in SFC. The selectivity of SFC has been effectively expanded, and the technique can be used for the separation of diverse analytes ranging from lipid compounds to polar compounds such as flavonoids, saponins, and peptides. The choice of stationary phase has a great impact on the separation effect of analytes in SFC. As new stationary phases for HPLC are constantly investigated, specialized stationary phases for SFC have also been continuously developed. Researchers have discovered that polar stationary phases containing nitrogen heterocycles such as 2-EP and PIC are highly suitable for SFC because they can effectively manage the peak shape of alkaline compounds and provide good selectivity in separating acidic and neutral compounds.The development of various stationary phases has promoted the applications of SFC in numerous fields such as pharmaceuticals, food production, environmental protection, and natural products. In particular, natural products have specific active skeletons, multiple active groups, and excellent biological activity; hence, these materials can provide many new opportunities for the discovery of novel drugs. According to reports, compounds related to natural products account for 80% of all commercial drugs. However, natural products are among the most challenging compounds to separate because of their complex composition and low concentration of active ingredients. Thus, superior chromatographic methods are required to enable the qualitative and quantitative analysis of natural products. Thanks to technological improvements and a good theoretical framework, the benefits of SFC are gradually becoming more apparent, and its use in separating natural products is expanding. Indeed, in the past 50 years, SFC has developed into a widely used and efficient separation technology. This article provides a brief overview of the characteristics, advantages, and development process of SFC; reviews the available SFC stationary phases and their applications in natural products over the last decade; and discusses prospects on the future development of SFC.

The evolution and current state of instrumentation for analytical supercritical fluid chromatography.

Supercritical fluid chromatography has contributed significantly to chiral method development and semi-preparative purification in drug discovery, where sensitivity was not an issue. Now, analytical scale SFC's have been validated using a multi-vendor, inter-lab study for quantitation of achiral trace pharmaceutical impurities using sub-2 µm particles, with gradient elution, and UV detection. This should significantly increase the penetration of SFC into both chiral and achiral QA/QC applications. However, there is still work to be done. Extra-column dispersion is no better than previous generations, yet the technique is often superficially called "ultra high performance" SFC (UHPSFC), simply because sub-2 µm packings are used. Dispersion is far too high for use with sub-2 µm particles, requiring extensive hardware modification to use such particles with high efficiency. However, the most common means of reducing system dispersion in ultra high performance liquid chromatography (UHPLC) results in distortion of kinetic performance in SFC. Vendors need to specify or provide standardized plumbing schemes that allow the full use of sub-2 µm fully porous, and sub-3 µm superficially porous particles, with reduced plate height, h ≈ 2 when k' ≈ 2. There is no consensus on how to best perform dynamic compressibility compensation, since each vendor uses different CO2 pump head temperatures, resulting in subtle differences in flow and composition between vendors.

Analytical lifecycle management for comprehensive and universal nitrosamine analysis in various pharmaceutical formulations by supercritical fluid chromatography.

Since the detection of nitrosamines (NA) in valsartan pharmaceuticals, over two years have passed. At present, the occurrence of NAs can be limited to a few drug substances and drug products, but it is already becoming apparent that the issue appears to be much bigger than initially thought. The impact on the global pharmaceutical market has been tremendous and the problem can be attributed mainly to uncritically adopted approval changes and the lack of suitable, modern analytical methods to detect those impurities in time. We hereby demonstrate how lifecycle management (LCM) can be used to develop and improve suitable and universal analytical methods within short time. The resulting SFC-MS/MS method is intended for a universal nitrosamine investigation in drug substances and drug products. Successful NA analysis was demonstrated for seven sartans, metformin, pioglitazone and ranitidine. Additionally, combination drug products, containing also amlodipine, hydrochlorothiazide, vildagliptin and sitagliptin, were analyzed successfully. The method achieved separation of 16 NAs in 4 min with a total run time of 11.5 min, utilizing a Supel Carbon porous graphitic carbon (PGC) column. Carbon dioxide together with 0.1% TFA in methanol as modifier were used as eluents and 0.35% formic acid in methanol as make-up solvent for mass spectrometric NA detection. By implementing LCM in this case study, development time was reduced and knowledge was implemented fast. At the same time, a high adaptability of this "vital" method was achieved, which makes it possible to implement the constantly changing regulatory requirements within the shortest possible time. Supplemental development data, according to the ICH guidelines Q8, Q12 and the proposed Q14 are disclosed, demonstrating the scientific Quality-by-Design (QbD) development approach, the "fitness for use" and the robustness of the analytical procedure. This method contributes to the still ongoing risk assessment process of the pharmaceutical industry and the regulatory agencies, in order to understand root causes of NA formation, maintain the drug supply and prevent drug shortage.

Ultra high efficiency/low pressure supercritical fluid chromatography (UHE/LP-SFC) for triglyceride analysis: Identification, quantification, and classification of vegetable oils.

Triglycerides of vegetable oils have been extensively studied. Non-aqueous reversed-phase liquid chromatography and silver-ion chromatography are most frequently used to achieve their separation. In previous works, we presented the use of supercritical fluid chromatography with long columns (75 cm) packed with fused-core particles to provide ultra-high-performance separations, with a low-toxicity fluid (carbon dioxide) compared to the usual liquid-phase methods. In the present paper, we describe the quantification of triglycerides with supercritical fluid chromatography and evaporative light-scattering detection. Thanks to the isocratic elution mode, this quantification can be simplified, assuming (a) identical response coefficients for compounds having a close structure, (as only triglycerides are quantified), and (b) constancy of the response coefficient along the analysis (no elution gradient). Therefore, the relative concentrations of triglycerides were easily assessed. Only one calibration curve for one reference compound (in this case triolein) was required. The resulting relative concentrations are in good accordance with the numerous publications available. Relative quantification with UV detection at 210 nm is also proposed, facilitated by the very low UV absorption of carbon dioxide and with a calibration curve taking account of the variation of UV response according to double bond number. Nineteen vegetable oils are compared. The identification of triglycerides was carried out based on previous knowledge of these oils, but also with the help of a Goiffon retention diagram, based on the relationship between the logarithm of retention factor and the total double bond number. Finally, cluster analyses were computed, based on evaporative light-scattering detection or UV quantification data. They allow a quick comparison of the triglyceride content between the oils, in the goal to exchange one by the other for certain applications, or to compare a new oil to well-known ones.

Interlaboratory study of a supercritical fluid chromatography method for the determination of pharmaceutical impurities: Evaluation of multi-systems reproducibility.

Modern supercritical fluid chromatography (SFC) is now a well-established technique, especially in the field of pharmaceutical analysis. We recently demonstrated the transferability and the reproducibility of a SFC-UV method for pharmaceutical impurities by means of an inter-laboratory study. However, as this study involved only one brand of SFC instrumentation (Waters®), the present study extends the purpose to multi-instrumentation evaluation. Specifically, three instrument types, namely Agilent®, Shimadzu®, and Waters®, were included through 21 laboratories (n = 7 for each instrument). First, method transfer was performed to assess the separation quality and to set up the specific instrument parameters of Agilent® and Shimadzu® instruments. Second, the inter-laboratory study was performed following a protocol defined by the sending lab. Analytical results were examined regarding consistencies within- and between-laboratories criteria. Afterwards, the method reproducibility was estimated taking into account variances in replicates, between-days and between-laboratories. Reproducibility variance was larger than that observed during the first study involving only one single type of instrumentation. Indeed, we clearly observed an 'instrument type' effect. Moreover, the reproducibility variance was larger when considering all instruments than each type separately which can be attributed to the variability induced by the instrument configuration. Nevertheless, repeatability and reproducibility variances were found to be similar than those described for LC methods; i.e. reproducibility as %RSD was around 15 %. These results highlighted the robustness and the power of modern analytical SFC technologies to deliver accurate results for pharmaceutical quality control analysis.

The Application of Supercritical Fluid Chromatography in Food Quality and Food Safety: An Overview.

Recently, supercritical fluid chromatography (SFC) has attracted considerable attention for their application in food analysis. The use of supercritical CO2 (SC-CO2), as a mobile phase for SFC, with its low viscosity and high molecular diffusiveness, results in shorter analysis time and lower consumption of organic solvents as compared to high-performance liquid chromatography (HPLC). In addition, with recent improvements in its detection system, SFC has shown satisfactory selectivity and sensitivity. Thus, although the composition of food is complex, SFC remains a powerful tool in food analysis with some simple sample pretreatment techniques, such as liquid-liquid extraction, solid-phase extraction, and QuEChERS. Here, we summarize the applications of SFC in food quality and safety from 2012 to 2018, and mainly focus on sample pretreatment strategies and analysis conditions.

Determination of the stoichiometry between a drug and its counter-ion by supercritical fluid chromatography using ultra-violet and evaporative light scattering detections: Application to ondansetron hydrochloride.

In this paper, a supercritical fluid chromatography method using ultra-violet and evaporative light scattering detections (SFC-UV/ELSD) has been developed and validated for the stoichiometry determination of an antiemetic drug with its counter-ion i.e. ondansetron hydrochloride. Seven stationary phases were first screened using a CO2-methanol-diethylamine mobile phase. Best conditions were determined using Derringer's desirability functions regarding chromatographic separation: selectivity, resolution, peak shape and runtime. The influence of co-solvent composition on resolution was evaluated. After optimization, best chromatographic results were obtained using 2-ethylpyridine stationary phase and a co-solvent composed of 0.2% diethylamine and 2% water in methanol. While ondansetron was quantified using UV detection (214 nm) and an external calibration curve, the determination of chloride was carried out using ELSD and an internal calibration curve. Then, the method was validated using the accuracy profile approach with a total error included in the ±10%. Finally, the proposed method was applied for the determination of the molar ratio between ondansetron and chloride. A value of 1.001 ± 0.003 demonstrated that the stoichiometry of this drug with its counter-ion was 1:1.

The development of a sub/supercritical fluid chromatography based purification method for peptides.

Peptide drugs are essential components of the pharmaceutical industry with a multiplicity of therapeutic properties, such as being anti-hypertensive, anti-microbial, anti-diabetic, and having anti-cancer potential. These molecules are similar in physiological structure and function to the body's endogenous signalling molecules and are therefore ideal candidates for the development of the next-generation of drugs. However, the purification of these peptides can be problematic due to poor solubility and stability, which often results in low peptide yields. Peptides are traditionally purified via RP-HPLC methods, which are tedious and employ harsh solvents that generate harmful waste to the environment. There is a growing need for more cost-effective and sustainable purification methods of these biologics. SFC can provide a greener peptide purification approach with more environmentally friendly mobile phases such as CO2 and methanol, which can easily be recycled with minimal environmental impact. Currently, there is limited knowledge regarding the SFC purification of peptides. Herein, this study investigated SFC methods to purify a tetrapeptide (LYLV), octapeptide (DRVYIHPF), and nonapeptide (LYLVCGERG) on commercially available columns at an analytical scale. The 2-ethyl pyridine column proved to be optimal based on its reproducibility, peak shapes, efficient separations, and retention factors with peptide recoveries ranging from 80 to 102%. The run times were reduced to 13 min, as opposed to the traditional RP-HPLC methods of 50 min, thus making this SFC method an efficient, greener, and more cost-effective approach for the purification of these peptides.

Simultaneous detection of nitrosamines and other sartan-related impurities in active pharmaceutical ingredients by supercritical fluid chromatography.

Since July 2018, the pharmacological class of "sartans" has been the subject of considerable media and analytical interest, as it became known that they are contaminated with nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodiisopropylamine (NDiPA). Previous compendial methods are not able to detect these new contaminants. Using the latest and innovative Quality-by-Design (QbD) approach, it has now been possible to develop an analytical method that enables to investigate sartans, such as valsartan and losartan. Also a large class of different nitrosamines in the ppb range and sartan-related impurities can thus be determined simultaneously in a single analysis using supercritical fluid chromatography (SFC). By using SFC, a broad spectrum of nonpolar and very polar impurities can be separated and analyzed in under 20 min. The analytical method developed is validated for limit testing according to ICH Q2(R1) and fulfills default thresholds of EMA and FDA for testing of drug substances and genotoxic impurities. Additionally, it can also be adapted to other pharmaceuticals that may be contaminated with nitrosamines, since tetrazole synthesis as the underlying cause of nitrosamine contamination is important for a set of other non-sartan drug substances.

Supercritical fluid chromatography applied to the highly selective isolation of urinary steroid hormones prior to GC/MS analysis.

To assess the presence of prohibited anabolic substances used to promote growth in livestock, calf urine is the most relevant matrix. However, the sample preparation methods (required to remove unwanted matrix components and fractionate isobaric species that may be unresolved by gas chromatography- mass spectrometry GC/MS) are long and complex. In this context, semi-preparative supercritical fluid chromatography (SFC) was considered to possibly simplify the sample preparation in reducing the number of procedures. Fifteen stationary phases were screened with SFC combined with UV and evaporative light-scattering detection (ELSD), among which two columns (Cosmosil π-NAP and Princeton DIOL) were retained for their ability to isolate steroid hormones from other matrix components and, for the second column, for the additional possibility to fractionate steroid hormones into different families (estrogens, mono-hydroxylated and di-hydroxylated androgens). The fractions were further analysed with GC/MS showing the benefit of class fractionation. The final method allows for significant time, solvent and money savings compared to the previously widely used method (solid-phase extraction combined with semi-preparative high-performance liquid chromatography).

Implementation of a generic SFC-MS method for the quality control of potentially counterfeited medicinal cannabis with synthetic cannabinoids.

In this study, we describe the development of a SFC-MS method for the quality control of cannabis plants that could be potentially adulterated with synthetic cannabinoids. Considering the high number of already available synthetic cannabinoids and the high rate of development of novel structures, we aimed to develop a generic method suitable for the analysis of a large panel of substances using seventeen synthetic cannabinoids from multiple classes as model compounds. Firstly, a suitable column was chosen after a screening phase. Secondly, optimal operating conditions were obtained following a robust optimization strategy based on a design of experiments and design space methodology (DoE-DS). Finally, the quantitative performances of the method were assessed with a validation according to the total error approach. The developed method has a run time of 9.4 min. It uses a simple modifier composition of methanol with 2% H2O and requires minimal sample preparation. It can chromatographically separate natural cannabinoids (except THC-A and CBD-A) from the synthetics assessed. Also, the use of mass spectrometry provides sensitivity and specificity. Moreover, this quality by design (QbD) approach permits the tuning of the method (within the DS) during routine analysis to achieve a desirable separation since the future compounds that should be analyzed could be unknown. The method was validated for the quantitation of a selected synthetic cannabinoid in fiber-type cannabis matrix over the range of 2.5% - 7.5% (w/w) with LOD value as low as 14.4 ng/mL. This generic method should be easy to implement in customs or QC laboratories in the context of counterfeit drugs tracking.

Effect of density on kinetic performance in supercritical fluid chromatography with methanol modified carbon dioxide.

In a relatively recent reevaluation of the van Deemter Equation, Guiochon concluded that the mass transfer resistance in the mobile phase is independent of the retention factor. In the process he showed reduced plate heights ≈ 2 for a nearly unretained peak (k = 0.4) in high performance liquid chromatography (HPLC). In the present work, using supercritical fluid chromatography (SFC), efficiency was measured at various pressures, densities, and modifier concentrations. The highest efficiency, with a reduce plate height of hr = 1.63, was recorded with the lowest retention factor (k < 0.8). This is an extremely low hr for totally porous particles, at very low k, and appears to support Guiochon's analysis. The density of methanol/carbon dioxide mixtures were calculated using the REFPROP program from the National Institute of Standards and Technology (NIST) over a wide range of pressures and % methanol. The density of higher methanol concentrations (>20%), commonly used in SFC, was found to be lower than the density of lower concentrations (<20%). At low methanol concentrations, density varies widely with pressure. However, at high methanol concentrations there is very little change in density, and very little change in retention with pressure. With increasing modifier concentration, density decreases, while viscosity increases (ΔP increases). The pump and back pressure regulator (BPR) pressures are not necessarily good indicators of pressures or densities in the column. At high flow rates the extra-column pressure drop (ΔP) can be much larger than the column ΔP and can be unevenly distributed in front of and behind the column. In one extreme the ΔP after the column was 3 times higher (105 bar) than the actual column ΔP (32 bar).

On-line coupling of achiral Reversed Phase Liquid Chromatography and chiral Supercritical Fluid Chromatography for the analysis of pharmaceutical compounds.

On-line selective comprehensive two-dimensional chromatography combining Reversed Phase Liquid Chromatography and Supercritical Fluid Chromatography (sRPLCxSFC) was investigated for the analysis of chiral pharmaceutical compounds. Preliminary studies were carried out with the aim of overcoming instrumental constraints which are related to such 2D-coupling. The impact of both injection solvent and injection volume on the chiral SFC second separation was assessed with a view to limiting injection effects due to mobile phase compatibility issues between both dimensions. The resulting on-line sRPLCxSFC system was applied to the achiral x chiral analysis of a pharmaceutical sample. Using an Acquity BEH C18 column in the first dimension and a Chiralpak IC column in the second one, both chemical (achiral) and enantiomeric (chiral) purities could be evaluated in less than 50 min within a single run. Under such conditions, a detection limit of about 0.5% for R-enantiomer could be obtained with UV detection. The results obtained in sRPLCxSFC were compared to those obtained in conventional chiral 1D-SFC. Baseline resolution was obtained in both cases and the linearity in the detector response was on the same order of magnitude (R²â€¯> 0.99). Finally, despite current instrumental limitations (no commercially available system for sLCxSFC, large dwell volume and large extra-column volume in SFC), the on-line coupling of RPLC and SFC appears to be attractive and promising for rapid achiral/chiral analysis of complex pharmaceutical samples.

[Separation and purification of compounds from piper kadsura using preparative reversed-phase liquid chromatography and preparative supercritical fluid chromatography].

A method based on preparative reversed-phase liquid chromatography (prep-RPLC) and preparative supercritical fluid chromatography (prep-SFC) was developed for the separation and purification of compounds from piper kadsura. A pretreatment method was first developed, including methanol extraction, water precipitation, petroleum ether extraction, etc. Chlorophyll and other strong polar impurities were removed from the piper kadsura samples, and the target components were enriched in petroleum ether extracts. The piper kadsura samples were separated into 18 fractions on a Unitary C18 column (250 mm×20 mm, 5 µm) with water and methanol as the mobile phases. Then, the SFC parameters, including the column, modifier, temperature, and backpressure were optimized. The optimized conditions for prep-SFC were as follows:XAmide column (250 mm×20 mm, 5 µm), methanol as the modifier, 30℃ column temperature, and 15.0 MPa backpressure. Because of the good orthogonality of RPLC and SFC, six highly pure compounds were isolated, including kadsurenone, wallichinine, denudatin B, pellitorine, 2E-decenoic acid N-isobutylamide, and futoxide.