Determination of the bioavailability of intranasal elcatonin in humans: development of a sandwich transfer enzyme immunoassay for elcatonin.
A sandwich transfer enzyme immunoassay for elcatonin (ECT) and its usability for the pharmacokinetic study are described. The anti-salmon calcitonin (SCT) antibody was used for the present assay. The assay procedure consisted of the reaction of ECT with 2,4-dinitrophenylbiotinyl anti-SCT IgG and anti-SCT Fab'-beta-D-galactosidase conjugate, trapping onto (anti-2,4-dinitrophenyl bovine serum albumin) IgG-coated polystyrene balls, eluting with epsilonN-2,4-dinitrophenyl-L-lysine and transferring to streptavidin-coated polystyrene balls and fluorometric detection of beta-D-galactosidase activity. The practical detection limit of ECT was 0.15 pg (44 amol)/50 microl of sample and 3 pg/ml as the concentration. The application of this method has enabled us to directly estimate the bioavailability of ECT dosed intranasaly at a therapeutic level (100 IU, 17 microg) for its anti-osteoporotic effect as compared to an intramuscular dose (40 IU, 6.7 microg). The pharmacokinetic parameters of the intranasal ECT (n = 6) thus estimated were as follows: the area underthe serum concentration-time curve (AUC) = 2,570 +/- 1,650 (SD) pg x min/ml, and the maximal concentration (Cmax) = 60 +/- 25 (SD) pg/ml with the maximal time (Tmax) = 17.5 +/- 6.9 (SD) min, when the AUC for the intramuscular ECT (n = 9) = 9,460 +/- 5,870 (SD) pg x min/ml and the Cmax = 165 +/- 79 (SD) pg/ml with the Tmax = 16.1 +/- 4.2 (SD) min.
Kohno
T
T
Department of Environmental Health Sciences, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
Murasugi
N
N
Sakurai
H
H
Watabe
K
K
Nakamuta
H
H
Koida
M
M
Sugie
Y
Y
Ogouchi
T
T
Inoue
T
T
Yanaka
M
M
Nomura
M
M
Yanagawa
A
A
D000281:Administration, Intranasal; D001682:Biological Availability; D002116:Calcitonin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D004355:Drug Stability; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008875:Middle Aged; D017698:Postmenopause; D011786:Quality Control; D012680:Sensitivity and Specificity
D002116:Calcitonin; C012755:elcatonin