Resorbable Biomaterials Based on Calcium Phosphates: Determination of In Vitro Solubility Applying the ISO 10993-14 (First Experiences)

To guarantee of the security of ceramic medical products the identification and quantification of the current degradation products is required by the ISO 10993-14 standard. Two methods - the gravimetrical registration of the mass loss and the quantitative determination of the leached ions by spectrometric methods - are planned. When checking the application of the ISO standard to calcium phosphate ceramics that can be used as implant materials a considerable difference in the results obtained with both methods was observed. It seems to be that precipitation reactions are responsible for that situation. To clear up the influence of precipitation reactions on the results the working procedure of the ISO standard was slightly modified. A first interpretation of the results is tried.

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Is Quantitative Determination of Fibrin(ogen) Degradation Products and Thrombin-Antithrombin III Complexes Useful to Diagnose Deep Venous Thrombosis in Outpatients?

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647113 ◽

1989 ◽

Vol 62 (04) ◽

pp. 1043-1045 ◽

Cited By ~ 12

Author(s):

Paul F M M van Bergen ◽

Eduard A R Knot ◽

Jan J C Jonker ◽

Auke C de Boer ◽

Moniek P M de Maat

Keyword(s):

Quantitative Determination ◽

Venous Thrombosis ◽

Deep Venous Thrombosis ◽

Antithrombin Iii ◽

Degradation Products ◽

Family Doctor ◽

Diagnostic Value ◽

Impedance Plethysmography ◽

Fibrin Degradation Products

SummaryWe studied the diagnostic value of recently introduced ELISA’s for the determination of thrombin-antithrombin III (TAT) complexes, fibrin degradation products (FbDP), fibrinogen degradation products (FgDP) and total degradation products (TDP) for deep venous thrombosis (DVT) in plasma of 239 consecutive outpatients, suspected for DVT by their family doctor. DVT was confirmed by impedance plethysmography in 60 patients. Using the 95th percentile range of 42 healthy volunteers the sensitivity for the detection of DVT was: 37% for TAT, 95% for TDP, 92% for FbDP and 90% for FgDP. Specificity was: 88% for TAT, 16% for TDP, 20% for FbDP and 25% for FgDP.We conclude that these assays are of little value in the diagnosis of DVT in outpatients.

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Development and validation of the method for the quantitative determination of methotrexate in a transport medium by HPLC-MS/MS

Pharmacokinetics and Pharmacodynamics ◽

10.37489/2587-7836-2021-1-45-51 ◽

2021 ◽

pp. 45-51

Author(s):

P. Yu. Mylnikov ◽

Yu. Tranova ◽

A. V. Shchulkin ◽

E. N. Yakusheva

Keyword(s):

Quantitative Determination ◽

Gradient Elution ◽

Sample Volume ◽

Transport Medium ◽

Mass Selective Detector ◽

Transporter Protein ◽

Wide Range ◽

Separation Temperature

Relevance. BCRP is an efflux transporter protein that plays an important role in the pharmacokinetics of a wide range of drugs. The BCRP activity in vitro experiments is assessed by the transport of transporter protein substrates (methotrexate, etc.) across the bilipid membrane of cells overexpressingBCRP, for example, Caco-2 cells. The aim is to develop and validate a method for the quantitative determination of the BCRP substrate, methotrexate, in the transport medium of Caco-2 cells by HPLC-MS/MS. Methods. The work was performed on an Ultimate 3000 HPLC chromatograph (ThermoFisher, USA) with a TSQ Fortis tandem mass-selective detector (ThermoFisher, USA). The conditions of chromatographic analysis were as follows: column UCT Selectra C18 4.6 mm * 100 mm 5um, 100A, Selectra C18 Guard Cartridges SLC-18GDC46-5UM, separation temperature 35 °С, flow rate 0.3 ml/min, injected sample volume - 2 μl, analysis time - 10 min. Used a gradient elution: the ratio of the solution of 0.1 % formic acid and acetonitrile was at 0 min 75 and 25 %; 0.4 min 60 and 40 %; 6 minutes 20 and 80 %; 8 minutes 75 and 25 %. Under these conditions, the retention time of methotrexate is 3.11 minutes. Detection conditions: methotrexate - positive ionization mode, 455.15 m / z → 308.125 m / z, collision energy 22.99 V, source fragmentation 5, CID gas pressure 2 mTorr. The extraction of methotrexate from the transport medium (Hanks solution with 25 mM Hepes and 1% dimethyl sulfoxide) after incubation with Caco-2 cells for 3 h was carried out with a mixture of methanol + water in a ratio of 1: 1. Results. The developed method was validated according to the following parameters: selectivity, linearity, accuracy, precision, limit of quantitative determination, sample transfer, sample stability. The confirmed analytical range of the method was 60 -10,000 nmol / L in the transport medium. Conclusions: a method for the quantitative determination of methotrexate in the transport medium of Caco-2 cells by HPLC-MS / MS was developed and validated.

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Pegylated magnetic nanocarriers for doxorubicin delivery: A quantitative determination of stealthiness in vitro and in vivo

European Journal of Pharmaceutics and Biopharmaceutics ◽

10.1016/j.ejpb.2012.04.002 ◽

2012 ◽

Vol 81 (3) ◽

pp. 498-505 ◽

Cited By ~ 46

Author(s):

E. Allard-Vannier ◽

S. Cohen-Jonathan ◽

J. Gautier ◽

K. Hervé-Aubert ◽

E. Munnier ◽

...

Keyword(s):

Quantitative Determination ◽

Doxorubicin Delivery ◽

Magnetic Nanocarriers

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Organic/Inorganic bioactive materials Part III: in vitro bioactivity of gelatin/silicocarnotite hybrids

Open Chemistry ◽

10.2478/s11532-009-0078-z ◽

2009 ◽

Vol 7 (4) ◽

pp. 721-730 ◽

Cited By ~ 1

Author(s):

Lachezar Radev ◽

Maria Fernandes ◽

Isabel Salvado ◽

Daniela Kovacheva

Keyword(s):

Calcium Phosphate ◽

Hybrid Materials ◽

Calcium Phosphates ◽

Ceramic Powder ◽

Structure Evolution ◽

In Vitro Test ◽

In Vitro Bioactivity ◽

Bioactive Materials ◽

Vitro Test

AbstractIn this work we present our experimental results on synthesis, structure evolution and in vitro bioactivity assessment of new gelatin/silicocarnotite hybrid materials. The hybrids were obtained by diluting gelatin (G) and silicocarnotite (S) ceramic powder with G:S ratios of 75:25 and 25:75 wt.% in hot (40°C) water. The hybrids were characterized using XRD, FTIR, SEM/EDS and XPS. FTIR depicts that the “red shift” of amide I and COO− could be attributed to the fact that the gelatin prefers to chelate Ca2+ from S. The growth of calcium phosphates on the surface of the hybrids synthesized and then immersed in 1.5 SBF for 3 days was studied by using of FTIR, XRD and SEM/EDS. According to FTIR results, after an immersion of 3 days, A and B-type CO3HA can be observed on the surface. XRD results indicate the presence of hydroxyapatite with well defined crystallinity. SEM/EDS of the precipitated layers show the presence of CO3HA and amorphous calcium phosphate on the surface of samples with different G/S content when immersed in 1.5 SBF. XPS of the G/S hybrid with 25:75 wt.% proved the presence of Ca-deficient hydroxyapatite after an in vitro test for 3 days.

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