We discuss the origins and the fundamentals of Green Analytical Chemistry (GAC), based on the literature published about clean, environmentally-friendly or GAC methods. We pay special attention to the strategies and the tools available to make sample-pretreatment and analytical methods greener. We consider that the main principles are to replace toxic reagents, to miniaturize and to automate methods, making it possible to reduce dramatically the amounts of reagents consumed and wastes generated, so reducing or avoiding side effects of analytical methods. We also consider on-line decontamination or passivation of wastes to be of special interest in making analytical chemistry sustainable.

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Green Analytical Chemistry

Validation of bioanalytical LC-MS/MS assays: evaluation of matrix effects.

: Rapamycin is a new antifungal antibiotic produced by Streptomyces hygroscopicus NRRL 5491. It was isolated from the mycelium by solvent extraction, purified by silica gel column chromatography and crystallized as a colorless solid which melts at 183 approximately to 185 degrees C and has the empirical formula C56H89NO14. From its characteristic ultraviolet absorption spectrum rapamycin can be classified as a triene. It is highly active against various Candida species, especially Candida albicans. Its activity is compared with that of amphotericin B, candicidin and nystatin.

Rapamycin (AY-22,989), a new antifungal antibiotic. II. Fermentation, isolation and characterization.:II. FERMENTATION, ISOLATION AND CHARACTERIZATION

Matrix-dependent signal suppression or enhancement represents a major drawback in quantitative analysis with liquid chromatography coupled to atmospheric pressure ionization mass spectrometry (LC-API-MS). Because matrix effects (ME) might exert a detrimental impact on important method parameters (limit of detection, limit of quantification, linearity, accuracy, and precision), they have to be tested and evaluated during validation procedure. This review gives a detailed description on when these phenomena might be expected, and how they can be evaluated. The major sources of ME are discussed and illustrated with examples from bioanalytical, pharmaceutical, environmental, and food analysis. Because there is no universal solution for ME, the main strategies to overcome these phenomena are described in detail. Special emphasis is devoted to the sample-preparation procedures as well as to the recent improvements on chromatographic and mass spectrometric conditions. An overview of the main calibration techniques to compensate for ME is also presented. All these solutions can be used alone or in combination to retrieve the performance of the LC-MS for a particular matrix-analyte combination.

An overview of matrix effects in liquid chromatography-mass spectrometry.

A review of current trends and advances in modern bio-analytical methods: chromatography and sample preparation.

Background: Plasma/cerebrospinal fluid (CSF) ratio of compound K was determined to be lower than predicted during the conduct of clinical study. This triggered the evaluation of nonspecific binding of drug K and an additional ten compounds in CSF to collection tubing. Physiochemical properties such as pKa and log D values were correlated to the quantified results. Results: Mean recoveries of compound K quality controls sampled within 24 h, as compared with spiked quality control, were 12.9, 44.4 and 77.7% from silicone, Tygon® and Pharmed® collection tubing, respectively. Eight out of ten compounds showed significant loss into silicone and seven out of ten compounds showed no significant loss into Pharmed. Conclusion: Silicone tubing is not recommended and Pharmed appears to be most appropriate. CSF sample collection tubing must be evaluated prior to starting clinical studies.

Effect of sample collection tubing type used in a clinical study on quantitation of pharmaceutical compounds in CSF by LC–MS/MS

Background: A semi-automated 96-well protein precipitation followed by HPLC–MS/MS method for the determination of atrasentan (2R-[4-methoxyphenyl]-4S-[1,3-benzodioxol-5-yl]-1-[N,N-di-(N-butyl)-aminocarbonyl-methyl]-pyrrolidine-3R-carboxylic acid) in mouse whole blood was developed, validated and utilized in GLP toxicokinetic evaluations. Six 40-µl whole blood samples were collected from a single mouse over the course of a 12 h blood collection window. To avoid sample volume losses, whole blood was selected as the matrix in place of the more typically used plasma. A 10-µl assay volume was used to ensure sufficient volumes are available for dilutions, repeats and incurred sample reanalysis. The samples (10-µl aliquot) were fortified with stable-labeled internal standard (d18-atrasentan) and lysed thoroughly prior to protein precipitation. The chromatographic separation was performed on a Zorbax® SB-C18 (50 x 2.1 mm; 5 µm) HPLC column with a mobile phase consisting of 25 mM ammonium acetate and 0.25% (v/v) a...

Toxicokinetic evaluation of atrasentan in mice utilizing serial microsampling: validation and sample analysis in GLP study

A fully automated 96-well On-Line Solid Phase Extraction (SPE) followed by High Performance Liquid Chromatography (HPLC)-Tandem Mass Spectrometric (MS/MS) method for the determination of ABT-925 (2-{3-[4-(2-tert-Butyl-6-trifluoromethyl-pyrimidin-4-yl)-piperazin-1-yl)-propyl-sulfanyl}-3H-pyrimidin-4-one fumarate) in human plasma was developed, validated and utilized in Phase II clinical studies. 50 µL of plasma sample was fortified with internal standard (IS, d8-ABT-925) and extracted on-line with Cohesive Turbo Flow Cyclone P HTLC column. The chromatographic separation was performed on Aquasil C18 (3 μm 50 × 3 mm) HPLC column with a mobile phase consisting of 50/50/0.1 (v/v/v) ACN/H₂O/formic acid. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM) of m/z 457.4 → 329.4 for analyte and m/z 465.5 → 337.5 for IS.The peak area ratio (analyte/IS) was used to quantitate ABT-925. A dynamic range of 0.0102 μg/mL to 5.24 μg/mL was established after the validation. The validated method was then used for two Phase II studies. To demonstrate the method reproducibility, approximately 10% of the incurred samples from one study were repeated in singlet. The repeated values were compared to the initial values. All repeated values agreed within ±15% of the mean values.

https://www.mdpi.com/1999-4923/2/2/171/pdf

Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies

As an effective DPP-IV inhibitor, 2-(4-((2-(2S,5R)-2-Cyano-5-ethynyl-1-pyrrolidinyl)-2-oxoethylamino)-4-methyl-1-piperidinyl)-4-pyridinecarboxylic acid (ABT-279), is an investigational drug candidate under development at Abbott Laboratories for potential treatment of type 2 diabetes. In order to support the development of ABT-279, multiple analytical methods for an accurate, precise and selective concentration determination of ABT-279 in different matrices were developed and validated in accordance with the US Food and Drug Administration Guidance on Bioanalytical Method Validation. The analytical method for ABT-279 in dog plasma was validated in parallel to other validations for ABT-279 determination in different matrices. In order to shorten the sample preparation time and increase method precision, an automated multi-channel liquid handler was used to perform high-throughput protein precipitation and all other liquid transfers. The separation was performed through a Waters YMC ODS-AQ column (2.0 x 150 mm, 5 microm, 120 A) with a mobile phase of 20 mm ammonium acetate in 20% acetonitrile at a flow rate of 0.3 mL/min. Data collection started at 2.2 min and continued for 2.0 min. The validated linear dynamic range in dog plasma was between 3.05 and 2033.64 ng/mL using a 50 microL sample volume. The achieved r(2) coefficient of determination from three consecutive runs was between 0.998625 and 0.999085. The mean bias was between -4.1 and 4.3% for all calibration standards including lower limit of quantitation. The mean bias was between -8.0 and 0.4% for the quality control samples. The precision, expressed as a coefficient of variation (CV), was < or =4.1% for all levels of quality control samples. The validation results demonstrated that the high-throughput method was accurate, precise and selective for the determination of ABT-279 in dog plasma. The validated method was also employed to support two toxicology studies. The passing rate was 100% for all 49 runs from one validation study and two toxicology studies.

LC-MS/MS determination of 2-(4-((2-(2S,5R)-2-Cyano-5-ethynyl-1-pyrrolidinyl)-2-oxoethylamino)-4-methyl-1-piperidinyl)-4-pyridinecarboxylic acid (ABT-279) in dog plasma with high-throughput protein precipitation sample preparation.

Tawakol A. El-Shourbagy

Papers

Effect of sample collection tubing type used in a clinical study on quantitation of pharmaceutical compounds in CSF by LC–MS/MS

Toxicokinetic evaluation of atrasentan in mice utilizing serial microsampling: validation and sample analysis in GLP study

Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies

LC-MS/MS determination of 2-(4-((2-(2S,5R)-2-Cyano-5-ethynyl-1-pyrrolidinyl)-2-oxoethylamino)-4-methyl-1-piperidinyl)-4-pyridinecarboxylic acid (ABT-279) in dog plasma with high-throughput protein precipitation sample preparation.

Current Methods for the Quantitative Analysis of Pharmaceutical Compounds from Whole Blood Matrix Using Liquid Chromatography Mass Spectrometry