Analytical Quality Control

Pfeiffer, Gertrude

doi:10.1007/978-94-009-6753-3_4

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…These different patterns are interpreted to mirror the level of resilience of the sample (Athmann et al, 2021). This method as well as others [copper chloride crystallization (Busscher et al, 2010) and circular chromatography (Pfeiffer, 1984;Kokornaczyk et al, 2016)] can be classified as metabolomic fingerprinting based on pattern formation, as introduced by (Doesburg et al, 2019). When this method was invented by Lily Kolisko in the 1920s (Kolisko, 1953;Kolisko and Kolisko, 1978;Steffen, 1983), it was named capillary dynamolysis.…”

Section: Metabolomic Fingerprinting Based On Pattern Formationmentioning

confidence: 99%

Chronobiology of Viscum album L.: a time series of daily metabolomic fingerprints spanning 27 years

Guglielmetti,

Baumgartner,

Scherr

et al. 2024

Front. Physiol.

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Introduction: European mistletoe (Viscum album L.) has been gaining increasing interest in the field of oncology as a clinically relevant adjunctive treatment in many forms of cancer. In the field of phytopharmacology, harvesting time is pivotal. In the last century, a form of metabolomic fingerprinting based on pattern formation was proposed as a way to determine optimal harvesting times to ensure high quality of mistletoe as raw material for pharmaceutical use. In order to further evaluate the information obtained with this metabolomic fingerprinting method, we analysed a large time series of previously undigitised daily mistletoe chromatograms dating back to the 1950s.Methods: These chromatograms were scanned and evaluated using computerized image analysis, resulting in 12 descriptors for each individual chromatogram. We performed a statistical analysis of the data obtained, investigating statistical distributions, cross-correlations and time self-correlations.Results: The analysed dataset spanning about 27 years, contains 19,037 evaluable chromatograms in daily resolution. Based on the distribution and cross-correlation analyses, the 12 descriptors could be clustered into six independent groups describing different aspects of the chromatograms. One descriptor was found to mirror the annual rhythm being well correlated with temperature and a phase shift of 10 days. The time self-correlation analysis showed that most other descriptors had a characteristic self-correlation of ∼50 days, which points to further infradian rhythms (i.e., more than 24 h).Discussion: To our knowledge, this dataset is the largest of its type. The combination of this form of metabolomic fingerprinting with the proposed computer analysis seems to be a promising tool to characterise biological variations of mistletoe. Additional research is underway to further analyse the different rhythms present in this dataset.

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Section: Metabolomic Fingerprinting Based On Pattern Formationmentioning

confidence: 99%

Chronobiology of Viscum album L.: a time series of daily metabolomic fingerprints spanning 27 years

Guglielmetti,

Baumgartner,

Scherr

et al. 2024

Front. Physiol.

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“…Absolute radionuclide purity is attained if no other radionuclides besides the one of interest is present [234]. A common method to analyze the radionuclide purity is to use high purity germanium (HPGe) gamma-ray spectrometry to determine the amount and identity of radionuclides present prior to patient treatment [234][235][236].…”

Section: Radionuclide Purity Of Radiopharmaceuticalsmentioning

confidence: 99%

Development of separation technology for the removal of radium-223 from decayed thorium-227 in drug formulations. Material screening and method development

Frenvik

Kristensen

Ryan

2015

Drug Development and Industrial Pharmacy

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Targeted thorium conjugates are currently being investigated as a new class of alpha-radiopharmaceuticals. The natural decay of thorium-227 ((227)Th) results in the ingrowth of radium-223 ((223)Ra). Consideration must, therefore, be given to define acceptable limits of (223)Ra in the drug product at the time of dose administration. By effective sequestration of (223)Ra, we aim to improve the radiochemical purity and extend the effective user window of drug products containing (227)Th. (223)Ra is the first progeny of (227)Th and the only one with a long half-life (days). We have, therefore, focused on the removal of this specific species since the progenies of (223)Ra will have a very limited lifetime in the formulation once (223)Ra is removed. In this study, we investigated a multitude of materials for their ability to reduce the (223)Ra level by: (1) passive diffusion or (2) by cartridge filtration on gravity columns. In addition, we probe the compatibility of these materials in the presence of antibody trastuzumab to assess the level of protein binding and estimate the quenching of radiolysis by binding of radionuclides. A screening matrix of organic and inorganic materials was established, i.e. strontium and calcium alginate gel beads, distearoyl phosphatidylglycerol (DSPG) liposomes, ceramic hydroxyapatite, Zeolite UOP type 4A and cation exchange resins AG50W-X8 and SOURCE 30S. First, passive diffusional uptake of (223)Ra by suspended materials present in the formulation was measured as a decrease in sample radioactivity after separation. Second, selected materials were packed on gravity columns in order to evaluate the efficiency of column separation versus diffusional adsorption. The retention of (223)Ra and (227)Th were characterized by measuring the radioactivity in the eluate and on the columns. Finally, the compatibility between trastuzumab, as a selected model antibody, and suspensions of the binding materials was analyzed during storage of the drug product in the presence of adsorbent. The formation of H2O2 was evaluated to measure the influence of radionuclide binding material on radiolysis in the formulation. All the materials bound (223)Ra by passive diffusional uptake ranging from 31% to 95% with DSPG liposomes demonstrating superiority at 95% efficiency. All materials suitable for assessment by gravity column filtration bound (223)Ra almost quantitatively (∼100%) and with minimal variation (relative standard deviation <1%). The uptake was significantly higher compared to passive diffusional uptake. Alginate gel beads, ceramic hydroxyapatite and SOURCE 30S reduced the antibody concentration in solution to 40-50% while the Zeolite UOP type 4A, AG50W-X8 resin and DSPG liposomes showed ≤10% reduction of antibody concentration. Ceramic hydroxyapatite significantly reduced H2O2 formed by radionuclide initiated radiolysis.

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“…Two years ago, at the Symposium in Elsinore, the analytical quality control of radiopharmaceuticals was reviewed in general (1). In the meantime some newer techniques have been developed, which will be described and discussed in this paper, namely: Method.…”

Section: Introductionmentioning

confidence: 99%

Quality Control of Radiopharmaceuticals: Recent Developments in Analytical Techniques

Pfeiffer¹

1986

Progress in Radiopharmacy

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Analytical Quality Control

Cited by 5 publications

References 34 publications

Chronobiology of Viscum album L.: a time series of daily metabolomic fingerprints spanning 27 years

Chronobiology of Viscum album L.: a time series of daily metabolomic fingerprints spanning 27 years

Development of separation technology for the removal of radium-223 from decayed thorium-227 in drug formulations. Material screening and method development

Quality Control of Radiopharmaceuticals: Recent Developments in Analytical Techniques

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