Mpeg oh

Analogous to the DE formulation process, 25 mg mPEG-OH (Creative PEGWorks) was dissolved in 1 mL DCM and sonicated with 200 μL DI for 0s, 30s, 60s, or 300s, followed by a second sonication of the same duration after the addition of 4 mL DI. Samples stir-incubated for 3h to evaporate off DCM, and were then frozen at −80°C, and lyophilized to a powder in a FreeZone 2.5 Liter −84°C Benchtop Freeze Dryer (Labconco). Between 4–6 mg of PEG lyophilized powder were added and sealed in Premium Hermetic Pan/Lid (DSC Consumables) sample holder. Samples underwent a heat/cool/heat/cool/heat ramp to a maximum temperature of 80°C and minimum temperature of −60°C with a ramp of 10°C/min. The temperature at which the minimum heat flow occurred on the third heat ramp was recorded as the melting point temperature of the sample.

25 mg mPEG-OH (Creative PEGWorks) or no polymer was dissolved in 1 mL DCM, TCM, or EtAc and sonicated with 200 μL DI for 0s, 30s, or 300s, followed by a second sonication of the same duration after the addition of 4 mL DI. Samples stir-incubated for 3h to evaporate off organic solvent. pH was measured with an accumet pH meter (Fisher Scientific).