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After performing liquid-liquid extraction with ethyl acetate and HCl, samples from 12 volunteers who performed sequential collections after taking a tablet of naproxen alone (n = 6) or associated with esomeprazole (n = 6) were analyzed in a triple quadrupole mass spectrometer 8040 LC MS/MS Shimadzu. Separation of naproxen and its main metabolite 6-O-desmethylnaproxen was performed in a Shim-Pack XR-ODS 75Lx2.0 column and C18 pre-column at 40°C using a mixture of methanol and ammonium acetate 10 mM (70:30, v/v) with an injection rate of 0.3 ml/min. The total analytical run time for each sample was 5 min. The association of naproxen with esomeprazole take considerably longer time to reach the maximum concentration [Tmax 0.17 h (interquartile range, 0.13–1.95) for naproxen alone and 13.18*h (interquartile range, 10.12–27.15) for naproxen with esomeprazole, p = 0.002], also to be eliminated [T1/2 0.12 h (interquartile range, 0.09–1.35) for naproxen alone and 9.16*h (interquartile range, 7.16–41.40) for naproxen with esomeprazole, p = 0.002] and lower maximum concentrations (Cmax 4.6 ± 2.5 ug/mL for naproxen alone and 2.04 ± 0.78* μg/mL, p = 0.038). The association of naproxen with esomeprazole showed increased values of AUC0-t [82.06* h*μg/mL (interquartile range, 51.90–157.00) with esomeprazole and 2.97 h*μg/mL (interquartile range, 1.82–7.84) naproxen alone, p = 0.002] in drug concentrations in relation to the naproxen tablet alone, probably, such differences are due to the delay in the absorption of naproxen when it is associated with the drug proton pump inhibitor, esomeprazole. As well as reduced values of full clearance when naproxen is combined with esomeprazole (0.07* μg/h (interquartile range, 0.005–0.01) with esomeprazole and 7.29 μg/h (interquartile range, 3.17–16.23) in naproxen alone, p = 0.002). Both naproxen and 6-O-desmethylnaproxen in saliva samples can be effectively quantified using LC-MS/MS, this methodology proved to be rapid, sensitive, accurate and selective for each drug and allows for the analysis of their pharmacokinetic parameters, in both situations. [ABSTRACT FROM AUTHOR]

Naproxen is a widely used non-steroidal anti-inflammatory drug for the control of postoperative inflammatory signs and symptoms in dentistry. Its association with esomeprazole has been widely studied and has yielded good results for the control of acute pain, even with the delayed absorption of naproxen owing to the presence of esomeprazole. To further understand the absorption, distribution, and metabolism of this drug alone and in combination with esomeprazole, we will analyze the pharmacokinetic parameters of naproxen and its major metabolite, 6-O-desmethylnaproxen, in saliva samples. A rapid, sensitive, and selective liquid chromatography-tandem mass spectrometric method for the simultaneous determination of naproxen and 6-O-desmethylnaproxen in saliva will be developed and validated. Sequential saliva samples from six patients will be analyzed before and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 6 8, 11, 24, 48, 72, and 96 h after the ingestion of one naproxen tablet (500 mg) and esomeprazole-associated naproxen tablets (500 + 20 mg), at two different times. After liquid-liquid extraction with ethyl acetate and HCl, the samples will be analyzed using an 8040 Triple Quadrupole Mass Spectrometer (Shimadzu, Kyoto, Japan). Separation of naproxen and its major metabolic products will be performed using a Shim-Pack XR-ODS 75Lx2.0 column and C18 pre-column (Shimadzu, Kyoto, Japan) at 40°C using a mixture of methanol and 10 mM ammonium acetate (70:30, v/v) with an injection flow of 0.3 mL/min. The total analytical run time will be 5 min. The detection and quantification of naproxen and its metabolite will be validated, which elucidate the pharmacokinetics of this drug, thereby contributing to its proper prescription for the medical and dental interventions that cause acute pain. [ABSTRACT FROM AUTHOR]

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is used worldwide to test and trace the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). "Extraction-less" or "direct" real time-reverse transcription polymerase chain reaction (RT-PCR) is a transparent and accessible qualitative method for SARS-CoV-2 detection from nasopharyngeal or oral pharyngeal samples with the potential to generate actionable data more quickly, at a lower cost, and with fewer experimental resources than full RT-qPCR. This study engaged 10 global testing sites, including laboratories currently experiencing testing limitations due to reagent or equipment shortages, in an international interlaboratory ring trial. Participating laboratories were provided a common protocol, common reagents, aliquots of identical pooled clinical samples, and purified nucleic acids and used their existing in-house equipment. We observed 100% concordance across laboratories in the correct identification of all positive and negative samples, with highly similar cycle threshold values. The test also performed well when applied to locally collected patient nasopharyngeal samples, provided the viral transport media did not contain charcoal or guanidine, both of which appeared to potently inhibit the RT-PCR reaction. Our results suggest that direct RT-PCR assay methods can be clearly translated across sites utilizing readily available equipment and expertise and are thus a feasible option for more efficient COVID-19 coronavirus disease testing as demanded by the continuing pandemic., Competing Interests: The authors have declared that no competing interests exist.