polo188Structure of Poloxamer 188, with two hydrophilic ends and a hydrophobic core in the middle. Currently, available literature depicts that P188 has a half-life of 18 hours after injection inPoloxamer 188 (P188) is a non-ionic amphiphilic copolymer. It prises a central chain of hydrophobic polyoxypropylene flanked at ends by hydrophilic polyoxyethylene.