Thanks for asking about (AI20, Maleimide-PEG-PLGA). We do have a few different MW sized of Maleimide-PEG-PLGA polymers in stock and can make others as well. What we have in-stock so far is as shown below.
cat# - (PEG-PLGA size Da)
AI49 (3400-10,000 (75:25 LA:GA))
AI52 (3400-60,000 (75:25 LA:GA))
We also have a variety of Mal-PEG-PLA's available as well. If you don't see the size or configuration you're looking for here let me know. We can generate different sizes as a customer request item.