| 摘要 |
<p>A vaginal ring comprises a supporting ring (1) free of active agent. A layer (2), which contains an active agent such as a steroid, is applied on its outer rim, optionally in a continuous groove provided in the supporting ring. This layer, in turn, is coated with a layer (3) devoid of active ingredient. All components preferably comprise an LTV silicone elastomer. The ratio of the thickness of the layer (2), containing an active agent, to the layer (3), free of active agent, is about 5-50 : 1. As a result, a longterm and uniform release rate is achieved for the active agent.</p> |
