PubMed · 5943204
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J W Grindlay, J C Wright. 1966-08-06. Simple preparative scale thin layer chromatography apparatus.. https://pubmed.ncbi.nlm.nih.gov/5943204/
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The interaction between 15 steroidal drugs and carboxymethyl-gamma-cyclodextrin (CM-gamma-CD) was studied by reversed-phase charge-transfer thin-layer chromatography and the relative strength of interaction was calculated. CM-gamma-CD formed inclusion complexes with each compound, the complex always being less hydrophobic than the uncomplexed drug. The inclusion-forming capacity of drugs differed considerably depending on their chemical structures. The linear correlation between the hydrophobicity and specific hydrophobic surface area of anticancer drugs indicated that they can be considered as a homologous series of compounds, although their chemical structures are different. Hydrophobicity of drugs significantly influenced the strength of interaction, indicating the involvement of hydrophobic forces in the binding of drugs to CM-gamma-CD. The marked influence of CM-gamma-CD on the hydrophobicity of drugs suggests that this interaction may modify the biological properties (adsorption, uptake, half-life, etc.) of drug-CM-gamma-CD complexes drug, resulting in modified efficacy.
Several methods for the quantitative analysis of sialic acids in glycoconjugates require that the sialic acid glycosidic bond be cleaved prior to assay. The conventional (L. Svennerholm, (1958) Acta Chem. Scand. 12, 547-554) procedure for the hydrolysis of complex carbohydrates such as gangliosides employs 0.1 n H+ at 80 degrees C for 60 min. Under these conditions, we find that the monosialoganglioside (GM1) yields less than 50% of the total sialic acid. However, 90% recovery of sialic acid was achieved by supplementing the hydrolysis mixture with 0.2% sodium dodecylsulfate (SDS) and increasing the temperature to 85 degrees C. During hydrolysis under these conditions, N-acetylneuraminic acid (NAN) is degraded at about 7% per hour. If the analytical values for GM1 are corrected for degradation, the recovery of NAN is essentially quantitative.
The method currently recommended for the preparation of technetium-99m bicisate (99mTc-bicisate) requires a lengthy 30-min incubation at room temperature. The purpose of this study was to evaluate an alternative method to shorten the preparation time. 99mTc-bicisate was prepared with 3.7 GBq (100 mCi) 99mTc according to the manufacturer's instructions, except for the final incubation step, which was replaced with the microwave heating procedure. A standard thin-layer chromatography (TLC) method (i.e., Baker-Flex silica gel IB-F TLC plate with ethyl acetate as mobile phase) was used for the determination of the radiochemical purity (RCP) of 99mTc-bicisate. Our evaluation with different microwave heating processes (300 W with different heating times) demonstrated that as the microwave heating temperature was increased (i.e., 44 masculine-71 masculine C), an increased percentage of samples reached 95% within 5 min post preparation (n=58). The highest RCP value (i.e., 97.4%+/-0.5%, n=10) could be obtained immediately after an 8-s microwave heating time at 300 W (microwave temperature at 69 masculine C), and an average RCP value of 96.4%+/-1.3% (n=90) was maintained throughout the 24-h evaluation period. However, the trend seemed to reverse at higher microwave temperatures (i.e., 76 masculine-90 masculine C), which reconfirmed our initial findings that overheating had no benefit for the preparation of 99mTc-bicisate. To ensure that temperature was the only determining factor, a hot water incubator set at 69 masculine C was used (n=6). Similar RCP results were achieved. In conclusion, the use of a microwave oven at a low heat cycle provides a rapid and efficient way to prepare 99mTc-bicisate.