Quantitative measurements nucleosides

In order to make quantitative measurements. Miles (1958f)) has determined integrated infrared absorption intensities for some nucleosides, nucleotides, and polynucleotides in DjO solution (Fig. 12.8 and Table 12.2) by application of Ramsay s method I (Ramsay, 1952). When there is a well-resolved band, the application of Ramsay s method encounters no difficulty, but when overlapping bands occur, as in uridine and its derivatives, some uncertainty exists in determining the halfband width of a particular band. (The half-band width is a factor in Ramsay s equation and is defined as, Av, 2 = the width of the band in cm" at half-maximum intensity.) The equation as used by Miles to obtain A, the true integrated absorption intensity... 

Other applications include bioequivalent measurements of bromazepam, an anticonvulsant, in human plasma. The lower limit of quantitation (LLOQ) was 1 ng/mL (Gongalves et al. 2005). Kuhlenbeck et al. (2005) studied antitussive agents (dextromethorphan, dextrophan, and guaifenesin) in human plasma LLOQ values were 0.05, 0.05, and 5 ng/mL, respectively. Other compounds studied were nucleoside reverse transcriptase inhibitors, zidovudine (AZT) and lamivudine (3TC) (de Cassia et al. 2004) and stavudine (Raices et al. 2003) in human plasma, and paclitaxel, an anticancer agent, in human serum (Schellen et al. 2000). 

Separation and Quantitation.—The specific radioactivity of [y-32P]ATP of very high activity (up to 240 Ci per millimole) may be measured by using it to phosphorylate [dT(pT)10] quantitatively, using polynucleotide kinase, isolating the labelled undecanucleotide, and measuring its activity.170 Isotope dilution is used to confirm the values. An alternative method of measuring specific radioactivities of ribo-nucleoside triphosphates utilizes a 3H-labelled nucleoside triphosphate (e.g. UTP) of unknown specific activity, a 14C-labelled nucleoside (e.g. ATP), a suitable primer in... 

In a series of pyrimidine cyclonucleosides, the magnitude of J(C1, H1 ) varies quantitatively with glycosidic bond conformation. Measurement of this coupling consteuit in pyrimidine nucleosides can be used to determine the range of allowed syn and anti conformations.In riqld cvclonucleosldes of adenosine,... 

Purine compounds were quantitated by high-performance liquid chromatography (HPLC). These procedures permited the simultaneous measurement of concentration and radioactivity of a purine compound separated by either reversed-phase (nucleosides and base) or anion-exchange (nucleotides) gradient HPLC. These HPLC procedures have been described in detail (3). 

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