Synthesis and characterization of digoxin-phospholipid conjugates

Abstract

The preparation of immunoreactive derivatives of digoxin for analytical applications is most often carried out by periodate cleavage of the terminal sugar ring (digitoxose) followed by reaction with an enzyme, protein, carrier, or related biological molecules. Here we report an improved and more efficient synthesis which was developed to provide digoxin-phospholipid conjugates useful for liposome immunoassay. The approach used involved the linking of the cleaved digitoxose through a carboxymethyl oxime functionality, which provides much improved yields of readily purified products. The synthetic modification should be applicable to the preparation of analogous phospholipid conjugates involving linkage through a sugar ring (digitoxin, ouabain, and related cardiac glycosides) or to those involving steroids (i.e., 3-digoxigenone) which can be modified to form oxime derivatives remote from key functionalities important for immunorecognition by specific antibody. The characterization of the digoxin-phospholipid conjugates with high-resolution NMR and fast atom bombardment mass spectrophotometry will also be discussed.

Combination of quantum dot fluorescence with enzyme chemiluminescence for multiplexed detection of lung cancer biomarkers

“…Dioxime active ester was synthesized as described previously with slight modification. 22 Briefly, the periodate solution (31 mg in 0.4 mL of distilled water) was slowly added into the digoxin (50 mg) in 1 mL of chloroform-methanol (2 : 1), while the reaction mixture was stirred under nitrogen. The reaction was complete in 15 min after the addition of periodate.…”

Fabrication of a nano polymer wrapping Meg3 ShRNA plasmid for the treatment of cerebral infarction

“…The use of anti-Tfr antibody (OX-26) to bind Tfr could realize brain target. OX26 [18] has been used to conjugate liposome-containing digoxin [19] and nanoparticles-containing loperamide to achieve brain-targeted delivery [16,20], which manifested good treatment effect through the receptor-mediated endocytosis. The c-poly glutamic acid (PGA) had been used as nanodrug carriers and could implement high DNA packet rate, lower side effects [21][22][23][24].…”