flashcards 10
(51 cards)
What are the primary applications of small molecule chromatography in pharmaceuticals?
It is used for isolating and purifying drug candidates, determining molecular structures (when coupled with MS), studying pharmacokinetics (ADME), assessing bioavailability, testing excipient compatibility, monitoring stability/degradation, performing quality control of raw materials and finished products, validating manufacturing processes, ensuring regulatory compliance, and detecting counterfeit drugs.
How does chromatography aid in the early stages of drug discovery?
By isolating active compounds from complex natural product extracts or synthetic libraries, allowing researchers to identify, quantify, and characterize potential drug candidates before further testing.
Why is coupling liquid chromatography with mass spectrometry (LC-MS) crucial in pharmaceutical analysis?
LC-MS provides precise identification and quantification of drug compounds and their metabolites in biological samples, facilitating structure elucidation, pharmacokinetic profiling, and sensitive detection of low-level impurities or degradation products.
What role does chromatography play in pharmacokinetic and metabolism studies?
It identifies and quantifies parent drugs and metabolites in biological matrices (e.g., blood, urine), enabling determination of absorption rates, distribution profiles, metabolic pathways, excretion rates, and residence times.
How is chromatography used to evaluate drug bioavailability?
By measuring drug and metabolite concentrations in plasma or other fluids at multiple time points after administration, researchers calculate parameters such as Cₘₐₓ (maximum concentration), AUC (area under the curve), and MRT (mean residence time).
In formulation development, how does chromatography assess excipient compatibility?
By detecting any interactions between the active pharmaceutical ingredient and excipients—such as the appearance of new peaks indicating degradation or binding—ensuring that excipients do not adversely affect drug stability or efficacy.
Why is stability testing by chromatography important for pharmaceuticals?
It detects and quantifies degradation products under various conditions (e.g., temperature, light, humidity), ensuring that the drug remains effective and safe over its intended shelf life and informing formulation adjustments if degradation is too rapid.
What is batch release testing, and how does chromatography support it?
Batch release testing verifies that each manufactured lot meets predefined criteria for identity, strength, purity, and quality. Chromatography checks for the correct concentration of active ingredients and absence of unacceptable impurities.
How does chromatography contribute to validating manufacturing processes in pharmaceutical production?
By monitoring samples at different stages—raw materials, intermediates, and final product—to confirm consistent composition, purity, and reproducibility, ensuring that the process reliably yields the intended product.
What is method validation in a regulatory context, and how does chromatography fit into it?
Method validation demonstrates that an analytical procedure is accurate, precise, specific, robust, and reproducible. Chromatographic methods must be validated according to pharmacopoeial guidelines (e.g., BP, USP, EP) before being used for quality control or regulatory submissions.
How does chromatography detect counterfeit pharmaceuticals?
By comparing the chromatographic profile of suspect samples against authentic standards; deviations in retention times or unexpected peaks indicate incorrect dosages, wrong active ingredients, or harmful contaminants in counterfeit drugs.
What is liquid chromatography–diode array detection (LC-DAD), and when is it typically used?
LC-DAD measures absorbance across multiple UV/Vis wavelengths simultaneously, allowing purity checks and stability testing of pharmaceuticals by observing characteristic absorbance spectra and identifying co-eluting impurities.
What distinguishes LC-MS from LC-DAD in pharmaceutical applications?
LC-MS offers higher sensitivity and molecular specificity, enabling precise quantification of drugs and metabolites in complex biological samples, whereas LC-DAD is primarily a spectral purity and concentration tool for more straightforward matrices.
Why is ongoing quality control critical throughout the pharmaceutical manufacturing process?
Continuous QC ensures that every production batch maintains consistent purity, potency, and safety, detecting deviations early and preventing substandard or contaminated products from reaching patients.
How do pharmacopoeial monographs specify chromatographic methods for drug analysis?
They provide detailed protocols—including column type, mobile phase composition, flow rate, temperature, sample preparation, injection volume, and detection wavelength—ensuring standardized, reproducible testing that meets regulatory requirements.
In environmental monitoring, what pollutants are commonly analyzed by chromatography?
Organic pollutants (e.g., pesticides, herbicides, PAHs, PFAS), industrial chemicals (e.g., PCBs, volatile organic compounds), and water- or soil-borne contaminants that pose risks to ecosystems and human health.
How does chromatography help enforce environmental regulations like the Clean Water Act?
By providing analytical data on pollutant concentrations in water, air, or soil samples, demonstrating compliance (or noncompliance) with legal limits and guiding remediation efforts or regulatory enforcement actions.
What are PFAS (“forever chemicals”), and why are they a significant environmental concern?
Per- and polyfluoroalkyl substances (e.g., PFOA, PFOS) are highly persistent, bioaccumulative chemicals used in many consumer products. They do not readily degrade, accumulate in water and organisms, and are linked to health risks such as cancer, thyroid disease, and liver dysfunction.
Why did it take decades for PFAS guidelines to be introduced despite known risks?
Although PFAS health risks were recognized in the 1960s, regulatory guideline development was delayed by complex risk assessments, slow policy processes, and widespread industrial use. Formal detection methods and permissible limits only emerged in the 2010s.
Which analytical technique is recommended by the U.S. EPA for PFAS detection, and why?
LC-MS/MS (liquid chromatography–tandem mass spectrometry) is recommended for its high specificity and sensitivity to detect low-level PFAS in environmental samples, allowing accurate quantification despite complex matrices.
How is solid-phase extraction used in environmental sample preparation for PFAS analysis?
Samples (e.g., water) are passed through SPE cartridges that retain PFAS, separating them from bulk matrix components. The retained analytes are eluted with organic solvents, concentrated via evaporation, and analyzed by LC-MS/MS for sensitive detection.
What types of food and beverage contaminants are routinely screened by chromatography?
Pesticide and herbicide residues, mycotoxins produced by molds, heavy metals (e.g., lead, mercury, arsenic—often detected via derivatization or ICP-MS after chromatographic separation), veterinary drug residues (antibiotics, hormones), and processing contaminants like acrylamide or furan.
How does chromatography detect mycotoxins in grains or stored foods?
After sample extraction and cleanup (e.g., immunoaffinity or SPE), chromatographic separation (often HPLC or UHPLC) isolates mycotoxins. Detection by DAD (for UV-active mycotoxins) or MS confirms identity and quantifies concentration, ensuring levels are below regulatory thresholds.
Why is fatty acid profiling by GC important for nutritional analysis?
Gas chromatography quantifies and separates fatty acid methyl esters, revealing the composition of saturated, monounsaturated, and polyunsaturated fatty acids (e.g., omega-3 vs. omega-6) in oils or food products, guiding dietary recommendations and product labeling.
