I found this online article, from drugs .com, announcing FDA approval of Flexbumin, 2005:
Historically, albumin has been packaged in glass bottles as a result of technical requirements related to manufacturing, including inertness, sturdiness and a high water vapor and oxygen barrier that no single plastic material has been able to fulfill.
Flexbumin uses Baxter’s…proprietary multi-layer system that helps maintain albumin quality and allows the solution to be stored at room temperature.