US EPA

1230540 

Journal Article 

Efficacy of Digibind versus Digifab in binding cinobufotalin 

Barrueto, F, Jr; Hirsch, ON; Mercurio-Zappalla, M; Hoffman, RS 

2003 

1 

Journal of Toxicology: Clinical Toxicology
ISSN: 0731-3810
EISSN: 1097-9875 

Marcel Dekker Journals, 270 Madison Ave. New York NY 10016-0602 USA 

41 

5 (Aug 2003) 

726-727 

Cane toad venom is used to prepare various Chinese medicines like Chan Su, Lu-Shen-Wan, and Kyushin and has resulted in lethal exposures. Cinobufotalin (CINB), a bufadienolide, is one component of this venom. Digibind registered (DB) has been shown to bind various bufadienolides but has never been compared to the new Fab preparation, DigiFab registered (DF). This study compares the binding of DB vs. DF to CINB. HPLC grade methanol was utilized to create a stock solution CINB then diluted with fresh frozen plasma to 50 mu g/mL. Stock solutions of DB and DF were made with normal saline to a concentration of 200 mu g/mL. Three hundred micro litre aliquots of the DB and DF solutions were separated and then mixed with 2.7 mL of CINB solution so that the final DB and DF concentration was 20 mu g/mL. DB + CINB, DF + CINB, and an aliquot of just CINB solution were incubated at 37 degree C for 1 hour. The protein-free ultrafiltrate of the three aliquots was prepared by centrifuging a specimen with the Centrifree Micropartition system for 40 min at 1500g. Digoxin-equivalents were measured utilizing the turbidometric Tina Quant assay (Roche registered ) in triplicate for all specimens after centrifuging. The protein-free ultrafiltrate of CINB alone had a mean of 2.59 mu g/mL of digoxin-equivalents. The DF + CINB solution yielded a mean digoxin-equivalent of 2.13 mu g/mL compared to 1.52 mu g/mL of the DB + CINB solution. Independent two tailed t-test showed a p