Simultaneous HPLC assay of 1-adamantanamine hydrochloride (amantadine) and its four related compounds [2-adamantanamine hydrochloride (2-ADA), 1-adamantanmethylamine (ADAMA), 1-(1-adamantyl)ethylamine hydrochloride (rimantadine) and 3,5-dimethyl-1-adamantanamine hydrochloride (memantine)] in phosphate-buffered saline (pH 7.4) after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed. Phosphate-buffered saline samples were mixed with borate buffer and NBD-F solution in acetonitrile at 60 degrees C for 5 min and injected into HPLC. Five derivatives were well separated from each other. The lower limits of detection of amantadine, 2-ADA, ADAMA, rimantadine and memantine were 0.008, 0.001, 0.0008, 0.0015 and 0.01 microg/mL, respectively. The coefficients of variation for intra- and inter-day assay were less than 6.4 and 8.2%, respectively. The method presented was applied to a binding study of these compounds to human alpha(1)-acid glycoprotein. While affinity constants and capacities for ADAMA, rimantadine and memantine were calculated by means of Scatchard plots, those for the others were not determined. ADAMA, rimantadine and memantine were bound with different affinities and capacities. These results indicate that NBD-F is a good candidate as a fluorescent reagent to simultaneously determine amantadine and its four related compounds by HPLC after pre-column derivatization. Our method can be applied to binding studies for protein. 相似文献
Given a measurable space (T, F), a set X, and a map ?: T → X, the σ-algebras NФ = ??∈ΦN?, and MΦ = ??∈ΦN?, where G?(t) = (t, ?(t)) and Φ ? XT, are considered. These σ-algebras are used to characterize the (F, B, ?)-measurability of the compositions g ○ ? and f о G?, where g: X → Y, f: T × X → Y, and (Y, ?) is a measurable space. Their elements are described without using the operations ??1 and G??1. 相似文献
Reverse thermal gels have numerous biomedical implications, as they undergo physical gelation upon temperature increases and can incorporate biomolecules to promote tissue repair. Such a material is developed for the sustained release of bevacizumab (Avastin), a drug used to treat age‐related macular degeneration. The polymer, poly(ethylene glycol)‐poly(serinol hexamethylene urethane) (ESHU), forms a physical gel when heated to 37 °C and shows good cytocompatibility with ocular cells. ESHU is capable of sustaining bevacizumab release over 17 weeks in vitro, and the release kinetics can be altered by changing the drug dose and the ESHU concentration. These results suggest that ESHU is biologically safe, and suitable for ocular drug delivery.
The paper presents results of extensive experimental study of the water related continuum absorption in a mixture of water vapor and nitrogen in 107–143 GHz frequency range at accurately controlled laboratory conditions. Resonator spectrometer and modified method of measurement that minimizes systematic errors related to water adsorption were employed. It allowed investigation in temperature range 261–328 K, including a first-time laboratory study of the continuum at temperatures below freezing. Coefficients of the common empirical parameterization of the continuum including self (H2O–H2O) and foreign (H2O–N2) parts are derived and compared with results of the most known previous experimental and theoretical studies demonstrating very good qualitative and in some cases quantitative agreement. Dominating types of intermolecular interactions leading to the observed continuum are discussed. 相似文献