Development of a sensitive radioimmunoassay for Fab fragments: application to Fab pharmacokinetics in humans.
Pharm Res
; 10(5): 692-6, 1993 May.
Article
in En
| MEDLINE
| ID: mdl-8321833
ABSTRACT
Anti-sheep Fab fragment antisera were produced in rabbits using sheep digoxin-specific Fab fragments (Digidot) as immunogen. These antisera were used for the development of a radioimmunoassay (RIA) of sheep Fab fragments in human plasma and urine using 125I-labeled Fab fragments. Interference in the assays by digoxin, human proteins, and antibodies from different species was insignificant, but cross-reactivity between anti-sheep Fab antisera and goat IgG or Fab fragments was 22 to 67%. The limit of detection was 0.1 microgram/mL and the assay was linear over a 0.6-28 micrograms/mL range of Fab fragments. Intra- and interassay coefficients of variation were less than 6.9 and 10.5%, respectively. Accuracy of plasma and urine assays at various Fab fragment levels ranged from 96 to 106%. RIA was applied to the pharmacokinetic study of sheep digoxin-specific Fab fragments in one patient acutely intoxicated by digitoxin and treated with Digidot. The Fab elimination half-life was 12.1 hr. Steady-state volume of distribution and total-body clearance were 10.8 L and 23.4 mL/min, respectively. Unchanged Fab fragments (50 kD) and degradation products (25 kD) isolated by gel filtration chromatography of a urine sample cross-reacted with the anti-Fab antiserum.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Immunoglobulin Fab Fragments
/
Radioimmunoassay
/
Digoxin
Type of study:
Diagnostic_studies
Limits:
Animals
/
Female
/
Humans
/
Middle aged
Language:
En
Journal:
Pharm Res
Year:
1993
Document type:
Article
Affiliation country:
France