The registered chemist prepared research dosages according to the randomization schedule in the presence of quality assurance staff, under the guidance of the trained study staff. Investigational products were dispensed and then put into containers with the proper labels. To ensure proper administration of investigational products, an additional label was made available for affixing to each administration form for investigational products. As retention samples, the remaining investigational goods were kept in their original packaging. The doses of the supplied experimental products were transferred to the containers used for dispensing investigational products.