Browse every published article, from the latest research to earlier analysis. Use the page numbers below to explore the complete archive.
An enzyme can change the rate at which it processes one compound when another chemical is present. Whether the enzyme also turns over that second chemical is a separate question. What the researchers saw in two systems The investigators used human liver microsomes and nanodiscs containing CYP3A4. Enniatin B1 was metabolized in these systems, and…
Saliva can provide direct evidence that a drug or metabolite is present in that specimen. Using its concentration to estimate a blood value calls for a different validation. What the assay measured The investigators developed a liquid chromatography method with diode-array detection for five antipsychotics, carbamazepine and selected metabolites. The laboratory reported linearity from 10…
A laboratory may be able to distinguish a drug signal from background at a concentration too low to report as a reliable number. A study of four benzodiazepines in vitreous humor illustrates that distinction. What the validation established The researchers used liquid–liquid extraction and high-performance liquid chromatography with a diode-array detector. They tested flurazepam, lorazepam,…
In targeted mass spectrometry, a transition pairs the mass-to-charge ratio of a precursor ion with that of one of its fragments. An unrelated compound can produce signal in the same channel if its ions match the monitored masses. What overlapped in this assay Braun and colleagues screened more than 150 pharmaceuticals and metabolites in a…
An interaction measured with midazolam cannot be assigned to every medicine taken with the same inhibitor. Different probe drugs can reveal very different changes in exposure. What changed as the ASP8477 dose increased A clinical study used four probe drugs to assess activity of different cytochrome P450 enzymes. At the 100-milligram dose of ASP8477, the…
When a lab proposes a method for several drugs in one urine extract, the validation tells you which analytes, matrix and concentration range the results support. How the method was tested Choudhary and colleagues added known amounts of citalopram, prochlorperazine, midazolam and chlordiazepoxide to drug-free urine. They separated the compounds on a high-performance thin-layer chromatography…
The bispectral index (BIS) summarizes aspects of the brain’s electrical activity. Pulse oximetry estimates blood oxygen saturation. A prospective plastic-surgery study illustrates how the two measurements can diverge during the same procedure. How the investigators measured each outcome In 97 patients who received midazolam and ketamine under a preset protocol, researchers recorded BIS at four…
A cell assay can make midazolam metabolism look weak or strong depending on which liver model the researchers use. The choice matters when a toxicologist evaluates whether an experiment supports a proposed drug interaction. What the four models measured Berger and colleagues applied the same set of probe drugs to HepG2 cells, HepaRG cells and…
A result about waking to a sound does not necessarily predict waking to another stimulus. A mouse study compared an experimental orexin receptor antagonist, DORA-22, with triazolam and a vehicle control. What changed with the stimulus The researchers applied auditory, vestibular, olfactory, or low-oxygen stimuli after sleep began. In the sound experiment, the median time…
Reducing particle size can speed dissolution. A manufacturing step can also alter the way molecules pack in a solid, so a faster dissolution curve alone cannot show which change produced the result. What the formulation study measured The investigators compared dry grinding, rapid expansion of a supercritical solution, and a polymer-containing composite for the experimental…
A laboratory can identify acetaminophen in a specimen without establishing how it was taken. A postmortem series illustrates the difference between identifying a compound and linking it to the contents of a particular product. How the laboratory identified the compound The study described 47 specimens from 20 autopsies selected for suspected psychoactive substance overdose. The…
A droplet that dries into a ring can concentrate material at its edge. In a carbamazepine assay, the researchers used this effect to bring the drug into the area where they collected a Raman signal. What the measurement depended on The team extracted carbamazepine from serum, deposited a drop on a silicon substrate carrying silver…
An anesthesia trial can assign two drugs at fixed doses or titrate both to the same measured target. In the second design, the comparison concerns the strategies used to reach that target. A randomized trial comparing etomidate and propofol illustrates the distinction. What the researchers held constant Sixty adults scheduled for modified radical mastectomy received…
A formulation can release a drug slowly in a laboratory apparatus. Translating that curve into a prediction about absorption in a person requires evidence about what happens beyond the apparatus. What crossed the membrane? The investigators prepared polymer nanoparticles containing diazepam and hesperidin and varied polymer and stabilizer amounts. For an optimized formulation, they compared…
A receptor can move from the cell surface to an internal compartment while the total number of receptors remains stable. In cell experiments with the human serotonin 5-HT7 receptor, researchers measured both that movement and changes in receptor density. Which compounds changed both measurements? In engineered HEK293 cells, serotonin and several inverse agonists increased receptor…
Reducing a protein in neurons and removing it throughout an animal are different experiments. In a study of alcohol vapor exposure in fruit flies, the two interventions yielded different results for the ability to develop rapid tolerance. How the study defined tolerance The researchers used time to sedation as their behavioral endpoint. An increase in…
A late specimen can establish that a compound was still measurable at collection. Explaining why it was measurable requires a separate analysis. A case report on oseltamivir illustrates the difference when the parent drug and its active metabolite are measured together. What the investigators measured In serum collected 154 hours after the last dose, oseltamivir…
A drug can change a laboratory reaction even when the assay measures the breakdown of a different substance. Ascenzi and colleagues studied this distinction in an experiment with purified human serum albumin. Which substance did the assay track? The investigators measured the hydrolysis of three 4-nitrophenyl esters. Diazepam was one of five compounds they tested…
An accurate mass can narrow the list of candidate compounds while leaving multiple structures possible. In a fungal metabolite study, Clevenger and colleagues found one mass-to-charge value at two different retention times. They suspected two related forms of benzomalvin. What moved the identification beyond accurate mass The proposed formula agreed with the observed neutral mass…
Measuring total midazolam and measuring the amount unbound to plasma proteins present different analytical challenges. In a crossover study of nine healthy volunteers, Lammers and colleagues measured both after an overnight fast and after a 36-hour fast. Which samples could inform the free fraction? For midazolam, only the samples taken at the observed time of…
An abstract can give a different account of treatment from the case narrative. That matters when the report is cited as evidence that a specific drug was used during a poisoning episode. What the two sections reported Herath and colleagues described drowsiness, a heart rate of 55 beats per minute and blood pressure of 80/60…
A calibration study can include concentrations below the method’s reported limit of quantification. That distinction matters when a laboratory report uses a number near the bottom of the range. Rao and colleagues examined desvenlafaxine and alprazolam using HPLC with ultraviolet detection in spiked human plasma. What the paper reported for the lower end The reported…
A cannabinoid assay illustrates how sample mass and dilution connect an instrument result to the original product.
A laboratory study developed a color test for combined cannabinoids in plant samples and oral fluid.
A concentration above the highest calibrator creates a separate analytical question: can the laboratory dilute the sample and accurately recover its original concentration? Cui and colleagues tested that step while developing an LC–MS/MS assay for dexmedetomidine, dezocine, and midazolam in rat plasma. What the dilution experiment tested The calibration ranges topped out at 100 ng/mL…
A forum search can show that a treatment is being discussed outside clinical settings. Counting posts or threads answers a different question from counting patients. Floyd and colleagues looked at published reports and online discussions of baclofen use in gamma-hydroxybutyrate withdrawal. What the researchers found in each source The review identified 37 cases in the…
A facility can offer a rapid class screen while relying on a separate process for a quantitative toxicology result. Otani and colleagues asked Japanese emergency departments about both kinds of testing. What the survey counted Of 546 designated teaching institutions invited, 246 responded. The study reported which qualitative drug screening kits facilities used and separately…
A concentration in processed blood is only one part of a dose reconstruction. Zeilmaker-Roest and colleagues measured several perioperative drugs in blood collected for autotransfusion during congenital cardiac surgery. What the paired samples showed The study included 18 cell-salvage runs in 18 children. The investigators used liquid chromatography–tandem mass spectrometry to compare blood in the…
Drug accumulation can be expressed for a specific specimen, such as plasma, or for the whole animal. Those quantities should be kept separate. Muir and colleagues compared fish plasma and surface-water measurements in a wetland receiving treated wastewater in southern Ontario. What the field study measured The researchers studied caged and wild goldfish and wild…
One instrument injection can produce results for several drug classes. The scope of those results still depends on which compounds and concentration ranges the laboratory validated. Joye and colleagues developed a whole-blood procedure for compounds encountered in impaired-driving investigations. What the panel tested The method used 100 microlitres of whole blood, liquid chromatography and high-resolution…