摘要 |
A coating agent for delaying the release of a physiologically active substance to be administered per os to ruminants, comprising a veterinarially acceptable water-soluble, synthetic high molecular compound and ethylcellulose, said coating agent being stable in the first stomach of ruminants and capable of being effectively disintegrated in the fourth stomach of ruminants, characterized in that said coating agent further comprises at least one substance which is miscible with both of said high molecular weight compound and ethylcellulose and is insoluble in water. The coating agent protects the active substance from degradation in the first stomach of a ruminant at a pH of about 5.5 and rapidly breaks down in the fourth stomach at a pH of about 3, so releasing the active ingredient for absorption by the animal. |