perfusate

https://doi.org/10.1351/goldbook.10286

Stream of extraction phase entering a dialysis module.

Note: Perfusate is also used to describe the stripping phase in dialysis.
Source:
PAC, 2016, 88, 517. (Glossary of terms used in extraction (IUPAC Recommendations 2016)) on page 551 [Terms] [Paper]