| 摘要 |
<p>A controlled release composition for adminstering a therapeutic agent to a ruminant, using an intraruminal device, consists of a compressed tablet or bolus which comprises the therapeutic, a carrier material and optionally a bonding and/or slip agent. The carrier material is a surface-active material or an emulsifying agent which when mixed with the therapeutic agent is capable of forming a coherent tablet or bolus in a die under pressure, and when compressed into tablet or bolus and immersed in an aqueous medium, absorbs water at the tablet/water interface, to produce swelling of the material and a resulting water gel; said gel having a critical yield stress which is substantially lower than that of the dry material and which is not significantly lowered by further water adsorbed, and being capable of significantly reducing the rate of water penetration further into the body of the material beneath the gel. The intraruminal device pictured forms part of the invention. </p> |
