pro-vitrain

例句：

1. 1. The pro-vitrain was a key component in the synthesis process.
   前药是合成过程中的关键成分。
2. 2. The study of pro-vitrains has led to significant advancements in drug discovery.
   对前药的研究已经导致了药物发现的重大进步。
3. 3.Pro-vitrains are often used as starting materials for the production of pharmaceuticals.
   前药通常被用作生产药品的起始材料。