Methods for Analyzing Immunodeficiency Data with a Lower Limit of Quantification

2012 ◽  
Vol 01 (01) ◽  
Author(s):  
Getachew A Dagne
2020 ◽  
Vol 16 (3) ◽  
pp. 277-286
Author(s):  
Amal A. El-Masry ◽  
Mohammed E. A. Hammouda ◽  
Dalia R. El-Wasseef ◽  
Saadia M. El-Ashry

Background: The first highly sensitive, rapid and specific green microemulsion liquid chromatographic (MELC) method was established for the simultaneous estimation of fluticasone propionate (FLU) and azelastine HCl (AZL) in the presence of their pharmaceutical dosage form additives (phenylethyl alcohol (PEA) and benzalkonium chloride (BNZ)). Methods: The separation was performed on a C18 column using (o/w) microemulsion as a mobile phase which contains 0.2 M sodium dodecyl sulphate (SDS) as surfactant, 10% butanol as cosurfactant, 1% n-octanol as internal phase and 0.3% triethylamine (TEA) adjusted at pH 6 by 0.02 M phosphoric acid; with UV detection at 220 nm and programmed with flow rate of 1 mL/min. Results: The validation characteristics e.g. linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), accuracy, precision, robustness and specificity were investigated. The proposed method showed linearity over the concentration range of (0.5-25 µg/mL) and (0.1-25 µg/mL) for FLU and AZL, respectively. Besides that, the method was adopted in a short chromatographic run with satisfactory resolution factors of (2.39, 3.78 and 6.74 between PEA/FLU, FLU/AZL and AZL/BNZ), respectively. The performed method was efficiently applied to pharmaceutical nasal spray with (mean recoveries ± SD) (99.80 ± 0.97) and (100.26 ± 0.96) for FLU and AZL, respectively. Conclusion: The suggested method was based on simultaneous determination of FLU and AZL in the presence of PEA and BNZ in pure form, laboratory synthetic mixture and its combined pharmaceutical dosage form using green MELC technique with UV detection. The proposed method appeared to be superior to the reported ones of being more sensitive and specific, as well as the separation was achieved with good performance in a relatively short analysis time (less than 7.5 min). Highly acceptable values of LOD and % RSD make this method superior to be used in quality control laboratories with of HPLC technique.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3470
Author(s):  
Narae Hwang ◽  
Eunbin Chong ◽  
Hyeonju Oh ◽  
Hee Won Cho ◽  
Ji Won Lee ◽  
...  

Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are end-stage metabolites of catecholamine and are clinical biomarkers for the diagnosis of neuroblastoma. For the first time in Korea, we implemented and validated a liquid chromatography tandem mass spectrometry (LC–MS/MS) assay to measure urinary concentrations of HVA and VMA according to Clinical and Laboratory Standards Institute guidelines. Our LC–MS/MS assay with minimal sample preparation was validated for linearity, lower limit of detection (LOD), lower limit of quantification (LLOQ), precision, accuracy, extraction recovery, carryover, matrix effect, and method comparison. A total of 1209 measurements was performed to measure HVA and VMA in spot urine between October 2019 and September 2020. The relationship between the two urinary markers, HVA and VMA, was analyzed and exhibited high agreement (89.1% agreement, kappa’s k = 0.6) and a strong correlation (Pearson’s r = 0.73). To our knowledge, this is the first study to utilize LC–MS/MS for simultaneous quantitation of spot urinary HVA and VMA and analyze the clinical application of both markers on a large scale for neuroblastoma patients.


Author(s):  
Marcin Zawadzki ◽  
Grzegorz Kowalski ◽  
Agnieszka Chłopaś-Konowałek ◽  
Marta Siczek ◽  
Małgorzata Sobieszczańska ◽  
...  

Abstract This paper presents a rapid, sensitive and precise method developed and validated for the quantification of sufentanil in biological samples using ultra-performance liquid chromatography coupled with QqQ-MS-MS. Plasma samples were extracted with simple and fast liquid-liquid extraction (ethyl acetate, pH 9). Calibration curve showed linearity in the concentration range of 0.005–30 µg/L. The lower limit of quantification was 0.010 µg/L. The most important method features are low lower limit of quantification value, simple plasma extraction and small sample volume. This method is suitable not only for evaluation of the pharmacokinetics, toxicology, bioavailability and clinical pharmacology of sufentanil but also for the detection and identification of this compound in human plasma samples for forensic purposes.


2009 ◽  
Vol 92 (2) ◽  
pp. 663-671 ◽  
Author(s):  
Yan-Ling Qiao ◽  
Yu-Xin Sheng ◽  
Li-Qun Wang ◽  
Jin-Lan Zhang

Abstract A sensitive and specific method using rapid resolution liquid chromatography coupled with UV-Vis detection was developed for fingerprint analysis of Rhizoma coptidis and simultaneous determination of 4 alkaloids: jatrorrhizine, coptisine, palmatine, and berberine. Samples of R. coptidis grown under different cultivation conditions and from different habitats were analyzed. The analysis was performed using a reversed-phase octylsilyl (C8) column and gradient elution. The mobile phase consisted of acetonitrile and 20 mmol/L KH2PO4. Each analysis was completed within 3.5 min. The method showed good linearity within test ranges of 4.7547.50 g/mL for jatrorrhizine, 20.60164.80 g/mL for coptisine, 18.07180.73 g/mL for palmatine, and 89.70717.57 g/mL for berberine. The method showed good precision, repeatability, and stability for quantification of the 4 alkaloids. The lower limit of detection was 0.19 ng for jatrorrhizine, 0.21 ng for coptisine, 0.15 ng for palmatine, and 0.14 ng for berberine. The lower limit of quantification was 0.57 ng for jatrorrhizine, 0.82 ng for coptisine, 0.55 ng for palmatine, and 0.27 ng for berberine. The overall recovery ranged from 96.30 to 104.10 for the 4 alkaloids. The method is accurate, rapid, and convenient, and it is suitable for routine quality control of R. coptidis.


Author(s):  
Ankita Panchal ◽  
Gaurav Sanghvi ◽  
Ashish Vachhani ◽  
Navin Sheth ◽  
Devendra Vaishnav

A simple, sensitive, specific, and cost effective method for simultaneous determination of Aspirin and Rosuvastatin calcium was developed and validated in single dosage formulation. The sample solution of ASP and RSTC was prepared using methanol as a solvent. Separation of ASP and RSTC was achieved with a mobile phase consisting of 20 mM KH2PO4 : Methanol (30:70 v/v) at a flow rate of 1.0 ml/min. Separations were performed on Merck hibar 250-4.6 RP18 (5 µm) column (150 mm X 3.0 mm), using a Shimadzu Prominence HPLC system equipped with a Shimadzu SPD-20A detector, Rhenodyne 7725i injector with 20 μL loop, LC-20 AD pump, CBM-20 Alite controller and LC Solution software. Retention times of ASP and RSTC were 3.747 and 5.969 minutes respectively. Absolute recovery of ASP and RSTC was 100.3 and 100.03 % respectively. The lower limit of quantification (LLOQ) of ASP and RSTC was 0.3097 and 0.1063 ppm and lower limit of detection (LLOD) of ASP and RSTC was 0.01535 and 0.01358 ppm respectively. Linearity was established for the range of concentrations 15.00-90.0 μg/ml and 2.0-12.0 μg/ml for ASP and RSTC respectively with the coefficient of determination (R2) of 0.994 and 0.999 for both the compounds. The inter- and intra-day precision in the measurement of ASP quality control (QC) sample 75 μg/ml, were in the range 0.1-0.2 % relative standard deviation (R.S.D.) and 0.2-0.3 % R.S.D., respectively. The inter- and intra-day precision in the measurement of RST quality control (QC) sample 10 μg/ml, were in the range 0.1-0.2 % R.S.D., and 0.0-0.3 % R.S.D., respectively. The developed method would be applicable for routine quality control of ASP And RSTC in bulk as well as in pharmaceutical formulations


2016 ◽  
Vol 62 (1) ◽  
pp. 218-226 ◽  
Author(s):  
Mark M Kushnir ◽  
Alan L Rockwood ◽  
Frederick G Strathmann ◽  
Elizabeth L Frank ◽  
Joely A Straseski ◽  
...  

Abstract INTRODUCTION Parathyroid hormone–related peptide (PTHrP) is involved in activating pathways, allowing tumor cells to form bone metastases. Measurement of PTHrP is used for the diagnosis and clinical management of patients suspected of hypercalcemia of malignancy. We developed an LC-MS/MS method for measuring PTHrP, established sex-specific reference intervals, and assessed the method's performance. METHODS PTHrP was enriched from plasma samples with rabbit polyclonal anti-PTHrP antibody conjugated to magnetic beads. Enriched PTHrP was digested with trypsin, and PTHrP-specific tryptic peptide was analyzed with 2-dimensional LC-MS/MS in multiple reaction monitoring mode. RESULTS The lower limit of quantification was 0.6 pmol/L, and the upper limit of linearity was 600 pmol/L. Total imprecision was <10%. Very poor agreement was observed with the RIA (n = 207; Deming regression RIA = 0.059 × LC-MS/MS − 1.8, r = 0.483; Sy|x = 3.9). Evaluation of the clinical performance of the assay using samples from patients with and without hypercalcemia (n = 199) resulted in an area under the ROC curve of 0.874. In sets of consecutively analyzed routine samples of patients assessed for hypercalcemia, the PTHrP positivity rate by RIA (n = 1376) was 1.9%, and 26.6% by LC-MS/MS (n = 1705). Concentrations were below the lower limit of quantification in 95.6% of the samples by RIA and 2.0% by LC-MS/MS. CONCLUSIONS PTHrP is a normal constituent in circulating blood and its concentrations are substantially underestimated by commercial RIAs, causing false-negative results in samples from patients suspected of hypercalcemia. Our observations suggest a link between increased concentrations of PTHrP in postmenopausal women with low body mass index and increased incidence of osteoporosis.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S25-S26
Author(s):  
James Peterson ◽  
Daniel Drazan ◽  
Hanna Czajka ◽  
Jason Maguire ◽  
Jean-Louis Pregaldien ◽  
...  

Abstract Background Meningococcal serogroups A, B, C, W and Y cause nearly all meningococcal disease globally. Vaccination is complicated by different dosing recommendations for serogroup B (MenB) and quadrivalent (MenACWY) vaccines, which could be solved with a single pentavalent vaccine. This study in adolescents and young adults evaluated a new pentavalent MenABCWY vaccine that combines 2 licensed vaccines, MenB-FHbp (Trumenba®; bivalent rLP2086) and MenACWY-TT (Nimenrix®), into a single vaccine. Methods In this ongoing, randomized, controlled, observer-blinded, multicenter study (NCT03135834), MenB vaccine-naive and MenACWY-naive or -experienced healthy 10–25-year-olds were randomized 1:2 to MenABCWY (Month 0,6) or MenB-FHbp (Month 0,6) and MenACWY-CRM (Month 0). Immune responses were measured by serum bactericidal activity assays with human complement (hSBA) against serogroup A, C, W and Y strains and 4 diverse, vaccine-heterologous MenB strains. Endpoints included percentages of subjects achieving ≥ 4-fold rises in titers from baseline. Noninferiority of immune responses was assessed at the 10% margin (95% CI lower limit > −10%). Safety was assessed. Results Following dose 2, high percentages of MenABCWY (n=543) and MenB-FHbp (n=1057) recipients achieved ≥ 4-fold rises against each of the 4 MenB strains (75.8−94.7% vs 67.4−95.0%) and titers reaching at least the lower limit of quantification against all 4 strains combined (79.9% vs 74.3%; Figure 1A). MenABCWY was noninferior to MenB-FHbp for all 5 endpoints. MenABCWY was also noninferior to a single MenACWY-CRM dose with 75.5−96.9% and 93.0−97.4% of MenABCWY recipients after dose 1 or 2, respectively, achieving ≥ 4-fold rises against serogroup A, C, W and Y depending on prior MenACWY experience (Figure 1B). Local reactions and systemic events after MenABCWY or MenB-FHbp were similarly frequent, mostly mild/moderate in severity (Figure 2), and unaffected by MenACWY experience. Figure 1. Immune Responses as Measured in hSBA to (A) MenB Test Strains at 1 Month After Dose 2 and (B) MenA, MenC, MenW, and MenY Test Strains at 1 Month After Doses 1 and 2 Figure 2. (A) Local Reactions and (B) Systemic Events Reported Within 7 Days After Any Dose Conclusion MenABCWY 4-fold immune responses from baseline were robust and noninferior to MenB-FHbp and MenACWY-CRM administered separately. Vaccination was safe and well tolerated. The favorable benefit-risk profile supports further MenABCWY development as a simplified alternative to current meningococcal vaccination practices. Funded by Pfizer. Disclosures James Peterson, MD, Pfizer (Scientific Research Study Investigator) Daniel Drazan, MD, Pfizer (Scientific Research Study Investigator) Hanna Czajka, MD, PhD, Pfizer (Scientific Research Study Investigator) Jason Maguire, MD, Pfizer (Employee, Shareholder) Jean-Louis Pregaldien, MS, Pfizer (Employee, Shareholder) Ilkka Seppa, MD, Pfizer (Scientific Research Study Investigator) Roger Maansson, MS, Pfizer (Employee, Shareholder) Robert O’Neill, PhD, Pfizer (Employee, Shareholder) Annaliesa S. Anderson, PhD, Pfizer (Employee, Shareholder) Paul Balmer, PhD, Pfizer Inc (Employee, Shareholder) Johannes Beeslaar, MD, Pfizer (Employee, Shareholder) John L. Perez, MD, MA, Pfizer Inc (Employee, Shareholder)


OENO One ◽  
2004 ◽  
Vol 38 (3) ◽  
pp. 191 ◽  
Author(s):  
Jean-Claude Vidal ◽  
Camille Toitot ◽  
Jean-Claude Boulet ◽  
Michel Moutounet

<p style="text-align: justify;">This paper presents a protocol for the sampling of gases and the measurement of oxygen by the means of a polarographic probe after bottle corking. Analyses of certified standard gases were performed according to the standard protocol of the Office International de la Vigne et du Vin to characterize the polarographic probe and gas chromatography (GC) methods. Finally, analyses of bottles of wine were performed to compare the both methods, together with a method based on the measurement of dissolved oxygen before and after agitation of the bottle of wine.</p><p style="text-align: justify;">The polarographic method displays greater sensitivity and a lower limit of quantification (LQ) than the GC method. Uncertainty was found to be 0.51 % with the probe method. Although the study showed that the results of the indirect method differed from those of the probe and GC methods, especially for high oxygen contents, it enables wine companies to measure oxygen in the wine and in the bottle headspace using the same apparatus.</p>


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