Composite bolus and its use.

摘要

A composite bolus for sustained release of a sparingly soluble organic active material in the reticulo-rumen of an animal is produced by mixing together an adhesive comprising one or more insoluble thermosetting resins, which are highly substantive to glass when cured, with an equal or greater weight of a dispersion medium comprising one or more hydrophilic organic liquids which are miscible with or dissolve the uncured adhesive and phase separate from the adhesive when it is cured, to form a liquid binder; mixing the binder so formed with glass or other inorganic particles and particles of sparingly soluble active material to form a cake, the ratio of binder to particles being selected to ensure the presence of voids in the cake; and curing the adhesive to phase separate it and bond together the glass particles to form a rigid bolus. The invention also relates to a method for the sustained supply of an active substance to a ruminant animal.