Abstract
We previously developed radioimmunoassays (RIAs) for digitoxin and digoxin using antisera raised against digitoxin 3’-hemisuccinate-bovine serum albumin and digoxin 3’-hemisuccinate-bovine serum albumin conjugates, respectively. Very recently, we converted the RIA for digoxin to an enzyme immunoassay (EIA) system. Here, we aimed to convert the RIA for digitoxin to an EIA suitable for measuring serum digitoxin level in patients, using digitoxin 3’-hemisuccinate-β-D-galactosidase as an enzyme-labeled antigen. The developed EIA showed a quantification range of 1 to 70 ng/mL and exhibited high specificity for digitoxin, with low cross-reactivity to digitoxin metabolites. Compared with a commercial anti-digitoxin antiserum clinically used to monitor serum digitoxin level in patients, our antiserum showed much higher specificity for intact digitoxin. Intra- and inter-assay variations were less than 10.0% and 8.5%, respectively. Recovery was within the range of 93.7% - 107.5%. Mean digitoxin concentrations measured in serum samples (n = 26) from digitoxin-treated patients by EIA using our new antiserum and the commercial anti-digitoxin antiserum were 11.0 and 13.8 ng/mL, respectively. The present EIA, which is superior to RIA in terms of convenience and disposal of waste materials, is expected to be practically useful for clinical monitoring of intact digitoxin in serum.
Highlights
Digitalis glycosides, such as digitoxin and digoxin, are used clinically to treat congestive heart failure and atrialHow to cite this paper: Higashi, Y., Ikeda, Y., Douno, M. and Fujii, Y. (2016) Development of Highly Specific Enzyme Immunoassay for Monitoring Serum Digitoxin Level in Patients
Digitoxin can be prescribed even in patients with impaired renal function, since it is mainly metabolized in the liver, whereas digoxin is predominantly eliminated by the kidney
Digitoxin differs from digoxin in the absence of a hydroxyl group at the C-12 position, and administered digitoxin is metabolized to digoxin and other products in the body (Figure 1) [3]-[8]
Summary
Digitalis glycosides, such as digitoxin and digoxin, are used clinically to treat congestive heart failure and atrialHow to cite this paper: Higashi, Y., Ikeda, Y., Douno, M. and Fujii, Y. (2016) Development of Highly Specific Enzyme Immunoassay for Monitoring Serum Digitoxin Level in Patients. (2016) Development of Highly Specific Enzyme Immunoassay for Monitoring Serum Digitoxin Level in Patients. Shimada et al [9] and Thong et al [10] used conjugates in which the hapten was linked to the carrier protein at the C-12 (or C-17) and C-22 positions of digoxin, respectively These antisera exhibited high cross-reactivity with dihydrodigoxin, one of the metabolites of digoxin. Antiserum raised against digitoxin 3’-hemisuccinate-BSA (Antiserum-A) showed much higher specificity for intact digitoxin than did commercially available anti-digitoxin antiserum (Antiserum-B) We used these antisera for pharmacokinetic studies of digoxin in rats, and for measuring digoxin and digitoxin levels in human serum by RIA [13]-[17]. Several assay methods for digitoxin in biological samples have been developed using liquid chromatography/
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
