CroFab® [Crotalidae Polyvalent Immune Fab (Ovine)] is a sterile, nonpyrogenic,
purified, lyophilized preparation of ovine Fab (monovalent) immunoglobulin fragments
obtained from the blood of healthy sheep flocks immunized with one of the following
North American snake venoms: Crotalus atrox (Western Diamondback rattlesnake),
Crotalus adamanteus (Eastern Diamondback rattlesnake), Crotalus scutulatus
(Mojave rattlesnake), and Agkistrodon piscivorus (Cottonmouth or Water
Moccasin). To obtain the final antivenin product, the four different monospecific
antivenins are mixed. Each monospecific antivenin is prepared by fractionating
the immunoglobulin from the ovine serum, digesting it with papain, and isolating
the venom-specific Fab fragments on ion exchange and affinity chromatography
CroFab (crotalidae polyvalent immune fab ovine) is standardized by its ability to neutralize the lethal action of each
of the four venom immunogens following intravenous injection in mice. The potency
of the product will vary from batch to batch; however, a minimum number of mouse
LD50 neutralizing units against each of the four venoms is included
in every vial of final product, as shown in Table 1. For comparison, the minimum
potency of each monospecific component in the batches demonstrated to be efficacious
in clinical trials is also included in Table 1.
Table 1. Minimum Mouse LD50 Neutralizing Units*
for Each Venom Component
||Minimum Potency per Vial of CroFab
||Minimum Potency per Vial of Clinical Trial Batches
[95% Reference Interval]
[760 - 1200]
[1320 - 2250]
[8000 - 17860]
[580 - 980]
|* One neutralizing unit is determined as the amount of the
mixed monospecific Fab proteins necessary to neutralize one LD50
of each of the four venoms, where the LD50 is the amount of venom
that would be lethal in 50% of mice.
Each vial of CroFab (crotalidae polyvalent immune fab ovine) contains up to 1 g of total protein and sodium phosphate buffer consisting of dibasic sodium phosphate USP and sodium chloride USP. Thimerosal is used as a preservative in the manufacturing process, and as such, mercury is carried over into the final product at an amount no greater than 104.5 mcg per vial, which amounts to no more than 1.9 mg of mercury per dose (based on the maximum dose of 18 vials used in clinical studies of CroFab (crotalidae polyvalent immune fab ovine) ). The product is intended for intravenous administration after reconstitution with 10 mL of Sterile Water for Injection USP.
Last reviewed on RxList: 9/11/2008
This monograph has been modified to include the generic and brand name in many instances.