scholarly journals Development and validation of a novel HILIC method for the quantification of low-levels of cuprizone in cuprizone-containing chow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fengmei Zheng ◽  
Yiqing Lin ◽  
Pierre Boulas
Keyword(s):  
Animal Studies ◽  
Minor Component ◽  
Complex Nature ◽  
Ultrasound Assisted Extraction ◽  
Acceptance Criterion ◽  
Mobile Phases ◽  
Limit Of Quantitation ◽  
Low Levels ◽  
A Minor ◽  
Liquid Chromatographic

AbstractCuprizone is an amide compound that has been wildly used in various animal studies, such as in the investigation of remyelination in mouse model. It is important to control the amount of cuprizone dosed in animals to be consistent as different amounts may lead to different clinical observations. Cuprizone is usually administrated as a minor component (i.e., 0.3%) of a mixture with powdered or pelleted rodent chow. Its low content, combined with the complex nature of chow, represents a significant challenge for the quantification of cuprizone in the mixture. To the best of our knowledge, no method has been reported in the literature so far. In this study, a simple, selective, and sensitive hydrophilic interaction liquid chromatographic method was developed for the quantification of cuprizone in cuprizone pre-clinical formulations. The analytical method comprises a fast ultrasound assisted extraction with acetonitrile/water as a solvent followed by gradient separation using a Waters Xbridge HILIC column with 0.1% TFA in water and acetonitrile as mobile phases and UV detection at 220 nm. The specificity, linearity, accuracy, repeatability, and limit of quantitation (LOQ) of the method were established. The method was determined to be linear in the range of 10–200 μg/mL. Accuracy was assessed by spiking a chow placebo with various amounts of a cuprizone reference standard to achieve target concentration levels and the recoveries were within the acceptance criterion of 90–110% of the target concentrations. Repeatability was demonstrated at the nominal concentration of 100 µg/mL and LOQ level of 2.5 μg/mL. This method has been demonstrated to be suitable for its intended use and has been successfully applied to the quantification of low levels of cuprizone in chow formulations. It was found that the cuprizone content in chow could varied significantly between batches and the potential causes of the variability were investigated.

scholarly journals Analytical Determination of Virginiamycin Drug Residues in Edible Porcine Tissues by LC-MS with Confirmation by LC-MS/MS

2009 ◽  
Vol 92 (1) ◽  
pp. 329-339 ◽  
Author(s):  
Joe Boison ◽  
Stephen Lee ◽  
Ron Gedir
Keyword(s):  
Solid Phase ◽  
Minor Component ◽  
Analytical Determination ◽  
Porcine Liver ◽  
Solid Phase Extraction Cartridge ◽  
Muscle Tissues ◽  
Dried Extract ◽  
A Minor ◽  
Liquid Chromatographic

Abstract A liquid chromatographic-mass spectrometric (LC-MS) method was developed and validated for the determination and confirmation of virginiamycin (VMY) M1 residues in porcine liver, kidney, and muscle tissues at concentrations 2 ng/g. Porcine liver, kidney, or muscle tissue is homogenized with methanolacetonitrile. After centrifugation, the supernatant is diluted with phosphate buffer and cleaned up on a C18 solid-phase extraction cartridge. VMY in the eluate is partitioned into chloroform and the aqueous upper layer is removed by aspiration. After evaporating the chloroform in the residual mixture to dryness, the dried extract is reconstituted in mobile phase and VMY is quantified by LC-MS. Any samples eliciting quantifiable levels of VMY M1 (i.e., at concentrations 2 ng/g) are subjected to confirmatory analysis by LC-MS/MS. VMY S1, a minor component of the VMY complex, is monitored but not quantified or confirmed.

Interferences appearing in fluorometrically measured liquid-chromatographic profiles of creatine kinase isoenzymes in serum.

1980 ◽  
Vol 26 (6) ◽  
pp. 707-711 ◽  
Author(s):  
T D Schlabach ◽  
J A Fulton ◽  
P B Mockridge ◽  
E C Toren
Keyword(s):  
Creatine Kinase ◽  
High Performance ◽  
Minor Component ◽  
The Other ◽  
Present Evidence ◽  
Human Sera ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Measured Liquid ◽  
Chromatographic Profiles

Abstract We observed nonenzymic peaks when serum isoenzymes of lactate dehydrogenase (EC 1.1.1.27; LD) and creatine kinase (EC 2.7.3.2.; CK) were separated by “high-performance” liquid chromatography and detected by continuously monitoring the column effluent for enzyme activity. Such background peaks were particularly apparent in CK isoenzyme profiles obtained from human sera. We observed two nonenzymic peaks with fluorescence detection, one in the CK-MB region, the other in the CK-BB region. Serum albumin was a major component in the artifactual CK-MB peak, with lipoprotein as a minor component. We present evidence that the material responsible for the other peak fluoresced quite strongly and is mostly pre-albumin.

Osteonectin is a minor component of mineralized connective tissues in rat

1986 ◽  
Vol 64 (4) ◽  
pp. 356-362 ◽  
Author(s):  
Paul Zung ◽  
Carmelo Domenicucci ◽  
Safia Wasi ◽  
Fumiyuki Kuwata ◽  
Jaro Sodek
Keyword(s):  
Minor Component ◽  
Crystal Formation ◽  
Connective Tissues ◽  
Adult Rats ◽  
Virtual Absence ◽  
Mineralized Tissues ◽  
Low Levels ◽  
A Minor

Osteonectin is a major glycoprotein of porcine and bovine bones and teeth that is found associated with hydroxylapatite crystal surfaces. From the ability of osteonectin to bind calcium ions, it has been proposed as a possible nucleator of hydroxylapatite crystal formation. Analysis of hydroxylapatite-bound proteins of rat bone and dentine, however, has revealed that osteonectin represents only 2.5 ± 1.5% of the hydroxylapatite-bound protein in long bones, 0.9 ± 0.5% in calvariae, and < 0.1% in incisor dentine of animals of different ages. Further, in vivo pulse–chase studies carried out in young adult rats have shown osteonectin to be synthesized at low levels in these tissues. Similarly, low levels of osteonectin were synthesized by rat calvarial cells in vitro. In contrast, fibroblastic cells from periodontal ligament and gingiva synthesized significantly greater amounts of osteonectin. These studies indicate that the low quantities of osteonectin in rat mineralized tissues are a consequence of low rates of formation rather than being due to rapid turnover. The virtual absence of osteonectin in incisor dentine correlates with the lack of peritubular dentine in rat, whereas the low osteonectin content of rat bones may reflect differences in their structure and biophysical properties compared with bones of larger mammals.

Starch synthesis and localization in post-germination Pinusedulis seedlings

1994 ◽  
Vol 24 (7) ◽  
pp. 1457-1463 ◽  
Author(s):  
J. Brad Murphy ◽  
Mark F. Hammer
Keyword(s):  
Seed Germination ◽  
Starch Content ◽  
Starch Synthesis ◽  
Minor Component ◽  
Dry Weight ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Low Levels ◽  
Starch Conversion ◽  
A Minor

Following pine seed germination, lipids in the megagametophyte are converted to sucrose, which is transported to the emerging seedling to support its growth. In several conifer species, an increase in the seedling starch content following germination has been reported. To further characterize this phenomenon, starch accumulation and localization, starch synthase (EC 2.4.1.21) activity (both soluble and granule-bound), and partitioning of exogenous 14C-sucrose were determined following germination of pinyon (Pinusedulis Engelm.) seeds. Starch was a minor component in dry embryos, accounting for only 3% of the dry weight. Starch levels increased 22-fold and 15-fold in the cotyledons and hypocotyl, respectively, by 8 days after germination. Starch accumulated to 65% of the dry weight in the cotyledons and 46% in the hypocotyl. The root and epicotyl accumulated relatively low levels of starch, only about 7%. Starch was localized primarily in the cortex and pith of the hypocotyl, the cortex of the cotyledons, and the root cap. Only granule-bound starch synthase showed a significant increase in activity during germination, and its changes more closely followed the pattern of starch accumulation. Exogenous 14C-sucrose was partitioned primarily into starch. After a 24-h labeling period, starch in both the cotyledons and hypocotyl accounted for 38% of total label (61% of the incorporated label) in these organs. In the roots, starch accounted for only 2.5 and 14%, respectively, of the total and incorporated label. The spatial and temporal pattern of starch accumulation closely paralleled previously reported patterns for the activity of sucrose synthase, which is apparently associated with the sucrose–starch conversion. Starch accumulation in the seedling accounts for approximately 50% of the sucrose transported from the megagametophyte following pinyon seed germination. Thus, starch appears to serve as an important transitory carbon pool for the growing seedling and may serve additional functions during seedling development.

Interferences appearing in fluorometrically measured liquid-chromatographic profiles of creatine kinase isoenzymes in serum.

1980 ◽  
Vol 26 (6) ◽  
pp. 707-711
Author(s):  
T D Schlabach ◽  
J A Fulton ◽  
P B Mockridge ◽  
E C Toren
Keyword(s):  
Creatine Kinase ◽  
High Performance ◽  
Minor Component ◽  
The Other ◽  
Present Evidence ◽  
Human Sera ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Measured Liquid ◽  
Chromatographic Profiles

Abstract We observed nonenzymic peaks when serum isoenzymes of lactate dehydrogenase (EC 1.1.1.27; LD) and creatine kinase (EC 2.7.3.2.; CK) were separated by “high-performance” liquid chromatography and detected by continuously monitoring the column effluent for enzyme activity. Such background peaks were particularly apparent in CK isoenzyme profiles obtained from human sera. We observed two nonenzymic peaks with fluorescence detection, one in the CK-MB region, the other in the CK-BB region. Serum albumin was a major component in the artifactual CK-MB peak, with lipoprotein as a minor component. We present evidence that the material responsible for the other peak fluoresced quite strongly and is mostly pre-albumin.

TEMPORAL VARIATION OF THE MATING SYSTEM IN A NATURAL POPULATION OF JACK PINE

Genetics ◽  
1985 ◽  
Vol 109 (3) ◽  
pp. 569-584
Author(s):  
W M Cheliak ◽  
B P Dancik ◽  
K Morgan ◽  
F C H Yeh ◽  
C Strobeck
Keyword(s):  
Mating System ◽  
Pinus Banksiana ◽  
Minor Component ◽  
Linear Increase ◽  
Complex Nature ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Family Structures ◽  
Filial Generation ◽  
A Minor

ABSTRACT Mating system parameters of a northern conifer, Pinus banksiana Lamb., were estimated from allozyme polymorphisms. Seeds analyzed were obtained from serotinous cones of 30 individuals and represented four independent fertilizations in 1975, 1976, 1977 and 1978. Results indicated that a mixed mating system model, with a mean effective outcrossing rate of 88 ± 0.047%, described the mating system of this stand. However, there was an approximately linear increase in the apparent selfing rate from the oldest (1975) to the newest (1978) crop. Two hypotheses could account for these observations. First, there may have been changes in the mating system during the 4-yr period, but linearity of the differences observed in this study may have been due to chance. These changes were, however, independent of the variability of the observed pollen pool. This indicated that they were not a result of different proportions of outcrossed zygotes directly observed. Second, there could have been a more or less constant amount of selfing, followed by a differential loss of viability of selfed and outcrossed zygotes during the period of storage in the cones. Under this hypothesis, selfed zygotes are at a selective disadvantage relative to outcrossed zygotes. No differences in the mating system could be demonstrated among the three crown strata of this stand. There was significant interlocus heterogeneity in the filial generation genotypic distributions and in the estimated outcrossing rates, reflecting the complex nature of forces that can affect single-locus estimates. There was evidence of some additional inbreeding, possibly due to family structures in the stand; however, this was a minor component of the total inbreeding.

scholarly journals New Validated RP-HPLC Method for Simultaneous Estimation of Valsartan and Nebivolol in Bulk and Dosage Forms

2021 ◽  
pp. 56-65
Author(s):  
Bayan Albakour ◽  
Saleh Trefi ◽  
Yaser Bitar
Keyword(s):  
Minor Component ◽  
Dosage Forms ◽  
Hplc Method ◽  
Array Detector ◽  
Simultaneous Estimation ◽  
Reverse Phase ◽  
Ich Guidelines ◽  
Routine Work ◽  
A Minor ◽  
Liquid Chromatographic

The main reason of this work to develop a sensitive, rapid, economic, precise reverse phase liquid chromatographic method to separate and assay the simultaneous determination of Valsartan and Nebivolol as a minor component in bulk and dosage forms. The separation was carried out using SHIMADZU UV-photo diode array detector at 200, 245 nm for Nebivolol and Valsartan respectively equipped with reverse phase C18 column Sunniest 5μm, 4.6 mm, 250 mm at 40˚C oven temperature, flow rate of 1 mL/min with mobile phase consist of 70:30 methanol: 10 mM phosphate buffer pH=3. The retention time of Nebivolol and Valsartan were to be found at 4.3 min and 8 min respectively. The method was validated according to ICH guidelines. The linearity of the proposed method was investigated in concentration range of 45.8-229% r=0.9997 for Nebivolol and the range 55-166%, r=0.9999 for Valsartan. Robustness in the case of little change of some chromatographic conditions. Validation of the proposed method was carried out for its linearity, accuracy, precision, robustness and assay. This method can be applied easily in routine work analysis to detrmine the estimation of nebivolol and valsartan in bulk and dosage forms.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

scholarly journals Development and Validation of Stability-Indicating RP-HPLC Method for the Estimation of Lenalidomide and its Impurities in Oral Solid Dosage Form

2019 ◽  
Vol 35 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Somana Siva Prasad ◽  
G. V. Krishna Mohan ◽  
A. Naga Babu
Keyword(s):  
Limit Of Detection ◽  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Stability Robustness ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Limit Of Quantitation ◽  
Successful Separation ◽  
Quality By Design Approach

In this study, a novel, simple and precise RP-HPLC method has been developed for the quantitative analysis of Lenalidomide (LLM) in pharmaceutical formulations using analytical quality by design approach. An X-bridge-C18 column (150 mm × 4.6 mm × 3.5 µ) with mobile phases containing a Potassium dihydrogen orthophosphate anhydrous buffer and methanol in the ratio of (90:10 v/v) and (35:65 v/v) are used for the estimation of LLM and its degradation products. The flow rate of 0.8 mL/min is maintained and all degradation studies are performed at 210 nm using photodiode array (PDA) detector. Method Validation is carried out according to International Council for Harmonisation (ICH) guidelines and the parameters namely; precision, accuracy, specificity, stability, robustness, linearity, limit of quantitation (LOQ) and limit of detection (LOD) are evaluated. The present developed RP-HPLC method shows the purity angle of peaks is less than their threshold angle, signifying that it to be suitable for stability studies. Hence, the developed method can be used for the successful separation of LLM and its impurities in the pharmaceutical dosage formulations.

Liquid Chromatographic Determination of Amiodarone Hydrochloride and Related Compounds in Raw Materials and Tablets

1994 ◽  
Vol 77 (6) ◽  
pp. 1447-1453 ◽  
Author(s):  
Pauline M Lacrok ◽  
Norman M Curran ◽  
Wing-Wah Sy ◽  
Dennis K J Goreck ◽  
Pierre Thibault ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chromatographic Determination ◽  
Raw Material ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Amiodarone Hydrochloride ◽  
Related Compounds

Abstract A liquid chromatographic method for the determination of amiodarone hydrochloride and 10 related compounds in drug raw material and for assay of drug in tablets was developed. The method specifies a 3 jxm Hypersil nitrile column (150 × 4.6 mm), a mobile phase of 1 + 1 acetonitrile–ammonium acetate buffer (0.1 M adjusted to pH 6.0 with 0.1 M acetic acid), a flow rate of 1 mL/min, and detection at 240 nm. The lower limit of quantitation of the related compounds is 0.02% or less. Drug contents in 2 raw material samples were 100.1 and 99.9% and ranged from 98.2 to 99.4% in 3 tablet formulations. Impurity levels in 2 samples of raw material from different manufacturers were ca 0.4%. The presence of 3 of the known related compounds in these samples was confirmed by liquid chromatographymass spectrometry. The method applied to raw materials was evaluated by a second laboratory and found to be satisfactory.

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