Study of the distribution of albendazole-sulphoxide (ABZ-SO) in fertilized egg compartments

In order to use the chicken embryo in teratogenic studies, it is necessary to know the internal volume in which a xenobiotic distributes. The inoculation of a xenobiotic in one of the compartments of the fertilized egg is the usual technique used in these studies. Neither the concentration nor the moment in which the xenobiotic comes into contact with the chicken embryo have been considered. Predicting the internal volume of distribution in the egg from some of the external parameters that do not interfere with the normal development is necessary. A simple method to calibrate these external parameters and their correlation with the different compartments of the fertilized eggs as well as the different distribution of the xenobiotic in these compartments has been successfully demonstrated. After injection of ABZ-SO, the maximum concentration in the embryo is reached by 36 h. The mean AUC for the albumen (sharp and obtuse end), yolk, and embryo were 78.4, 40.7, 79.2, and 10.8 micrograms.h/ml respectively. The results obtained about the kinetics of the diffusion of ABZ-SO indicate that this compound does not have a homogeneous distribution in all the compartments of the fertilized egg. These results highlight that whenever fertilized eggs are used as a screening for the possible toxicity of a drug or other substances, the dose of the xenobiotic to be injected has to be precisely determined in accordance with the total volume and the stage of embryonic development selected to be affected, starting from the previous knowledge of when and how much substance accedes to the embryo.