USP溶出数据库里度他雄胺软胶囊的溶出方法如下：
Tier I: Dissolution Medium: 0.1 N HCI with 2% (w/v) sodium dodecyl sulfate (SDS) (900 mL)
Tier II: Dissolution Medium: 0.1 N HCI with pepsin (as per USP) (450 mL) for the first 25 minutes, followed by addition of 0.1 N HCI with SDS (4% w/v) (450 mL) for the remainder of the dissolution test.

请问是怎么操作的？是分两种情况吗，假如第一种方法测定不了，用第二种吗？还是可以分开用？