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Drug Substance and Excipient Characterization
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Parind M. Desai, Lai Wah Chan, Paul Wan Sia Heng
In addition to its application in the separation and identification of materials, chromatography is also employed to detect potential interactions between materials. Both thin-layer chromatography and liquid chromatography are commonly employed for this purpose. In thin-layer chromatography, the stationary phase consists of a powder adhered onto a glass, plastic, or metal plate. The powders commonly used are silica, alumina, polyamides, celluloses, and ion-exchange resins. Solutions of the drug, excipient, and drug–excipient mixture are prepared and spotted on the same baseline at one end of the plate. The plate is then placed upright in a closed chamber containing the solvent, which constitutes the mobile phase. As the solvent moves up the plate, it carries with it the materials. Those materials that have a stronger affinity for the stationary phase will move at a slower rate. The material is identified by its Rf value, which is defined as the ratio of the distance traveled by the material to the distance traveled by the solvent front. The position of the material on the plate is indicated by spraying the plate with certain reagents or exposing the plate to ultraviolet radiation. If there is no interaction between the drug and excipient, the mixture will produce two spots whose Rf values are identical to those of the individual drug and excipient. If there is interaction, the complex formed will produce a spot whose Rf value is different from those of the individual components.
Analysis of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Adriana Arigò, Mariosimone Zoccali, Danilo Sciarrone, Peter Q. Tranchida, Paola Dugo, Luigi Mondello
The Rf value is characteristic for any given compound on the same stationary phase using the identical mobile phase. Hence, known Rf values can be compared to those of unknown substances to aid in their identification (Wagner et al., 2003). On the other hand, separations in paper chromatography involve the same principles as those in TLC, differing in the use of a high-quality filter paper as stationary phase instead of a thin adsorbent layer, by the increased time requirements, and by poorer resolution. It is worth highlighting that TLC has largely replaced PC in contemporary laboratory practice (Poole, 2003).
Echinostoma
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Aleksandra Oliveira-Menezes, Júlia Peralta Gonçalves
Using high-performance thin-layer chromatography, Saric et al.97 determined metabolic changes in urine E. caproni mouse model. In urine of infected mice, significant changes in taurine and alanine excretion occur. Thus, the profile of urine by high-performance thin-layer chromatography serves as a supplement fecal examination to detect echinostome infections in mice.97
Cytotoxic effects of extracts obtained from plants of the Oleaceae family: bio-guided isolation and molecular docking of new secoiridoids from Jasminum humile
Published in Pharmaceutical Biology, 2022
Khaled Ahmed Mansour, Ahmed Elbermawi, Ahmed A. Al-Karmalawy, Mohamed-Farid Lahloub, Mona El-Neketi
Compound (1) was isolated from the ethyl acetate fraction as a white amorphous powder (4.7 mg), soluble in both MeOH and ethyl acetate and showing UV (MeOH) absorbance maximum at 238 nm, [α]20D −89.5 (c 0.16, MeOH) and IR bands (KBr) at 3372, 1655, and 1031 cm−1 which are characteristic for iridoids (Inoue et al. 1985, 1991; Chang et al. 2020). Thin layer chromatography using the solvent system Pet. ether-EtOAc (50:50 v/v) revealed a spot with RF value of 0.48, quenched UV light at 254 nm, and a brownish colour after heating with vanillin/sulfuric acid spray reagent at 105 °C for 1 min ESI-HRMS exhibited a cationized ion peak at m/z 417.1865 [M + Na]+ (calcd, 417.1884), consistent with the molecular formula C21H30O7 and indicating a DBE of seven.
Role of 2.4 GHz radiofrequency radiation emitted from Wi-Fi on some miRNA and faty acids composition in brain
Published in Electromagnetic Biology and Medicine, 2022
Suleyman Dasdag, Mehmet Zulkuf Akdag, Mehmet Bashan, Veysi Kizmaz, Nurten Erdal, Mehmet Emin Erdal, Mehmet Tughan Kiziltug, Korkut Yegin
Total lipids were extracted with chloroform–methanol (2/1 v/v) (Folch et al. 1957). During the extraction process, autoxidation of unsaturated fatty acids was minimized by adding 50 μL of 2% butylated hydroxytoluene (BHT) in chloroform (Stanley-Samuelson and Dadd 1983). Nonlipid contaminants were removed by extraction with 0.88% aqueous KCl (Folch et al. 1957). The extract was evaporated to dryness under a stream of nitrogen at room temperature. Thin layer chromatography (TLC) was used for separation of lipid classes. The petroleum ether/diethyl ether/glacial acetic acid (80/20/1, v/v) mobile phase was used to separate phospholipid and triacylglycerol fractions (Mangold 1969). For separation of phospholipid subclasses such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, TLC plates were completely wetted in 1.8% boric acid prepared in 100% ethanol, dried for 5 min and activated for 15 min at 100°C. The lipid extracts were loaded on the plates and rapidly placed in the chromatography tank containing chloroform/ethanol/water/triethylamine (30/35/7/35, v/v/v/v) (Vaden et al. 2005). The TLC plates were then dried at room temperature. The PL classes were detected under UV light after having sprayed 2′,7′-dichlorofluorescein on the TLC plates. The PL classes were then scrapped into separate test tubes, and their constitutive fatty acids were transmethylated through the addition of acidified (sulfuric acid, 1%) methanol for 2 h at 85°C 11. The resulting fatty acid methyl esters (FAMEs) were extracted with hexane.
In vivo trafficking of a tumor-targeting IgE antibody: molecular imaging demonstrates rapid hepatobiliary clearance compared to IgG counterpart
Published in OncoImmunology, 2021
Francis Man, Alexander Koers, Panagiotis Karagiannis, Debra H. Josephs, Heather J. Bax, Amy E. Gilbert, Tihomir S. Dodev, Silvia Mele, Giulia Chiaruttini, Silvia Crescioli, Jitesh Chauhan, Julia E. Blower, Margaret S. Cooper, James Spicer, Sophia N. Karagiannis, Philip J. Blower
Indium-111 (30–180 MBq) in 60–300 µL of 0.1 M hydrochloric acid (Curium, UK) was added to the DTPA-conjugated antibody (200–700 μg at 2–3 mg/mL in 0.2 M NH4OAc, pH 6) and incubated for 30 min at room temperature. Labeling efficiency was measured by radio-thin layer chromatography (radio-TLC) and high-performance liquid chromatography (radio-HPLC). Radio-TLC was performed on ITLC-SA paper strips (Varian) with a mobile phase of 0.1 M sodium citrate (pH 5) with 5 mM EDTA. The strips were analyzed using a Mini-Scan™ radioTLC linear scanner (LabLogic Systems) equipped with a gamma probe (LabLogic B-FC-3200). Radio-HPLC was performed on an Agilent 1200 system using a size-exclusion chromatography column (BioSep SEC-s2000, 300 × 7.8 mm, 5 μm particle size, 145 Å pore size; Agilent) and phosphate-buffered saline pH 7.4 containing 0.2 mM EDTA as mobile phase (1 mL/min). Signals were detected with a G1314B UV detector (Agilent) and a gamma probe (LabLogic B-FC-3200). As radiolabeling efficiencies of >94% were found, no post-labeling purification was required.