Table 1.

Summary of β-eliminative linker cleavage half-lives in PEG conjugates and hydrogels

Modulator	PEG*		Hydrogel†
	Drug release t1/2, d	Gel erosion tRGEL, d†	Drug release
			Total (L1 + L2) t1/2, d	From gel (L1) t1/2, d
ClPhSO2−	1.5	1.3	1.4	1.5
PhSO2−	3.0	2.3	2.7	3.3
MeOPhSO2−	6.7		5.5	8.0
MeSO2−	19		8.8	21
O(CH2CH2)2NSO2−	31	22
CN	100	105

*PEG data are from ref. 3.

^†Hydrogel gel erosion is from Fig. 3A; total aminoacetyl-fluorescence (AAF) released includes free and attached to PEG fragments as shown in Fig. 3B, and AAF released directly from gel is calculated using Eq. S6 and shown in Fig. S2.