Controlled Release of Ropivacaine from Single-Armed (1-PCL) and Four-Armed PCL (4-PCL) Microspheres

Table 1

Ring-opening polymerization of ε-CL catalyzed by Sn(Oct)₂.

Entry^a	Initiator	[]/[]	DP^b	Mn (kDa)^c	Mn (kDa)^d	PDI^d	Tg (^oC)^e	Tm (^oC)^e
1-PCL	Benzyl alcohol	1/100	106	12.2	8.3	1.39	-56.8	54.4
4-PCL	Pentaerythritol	1/100	27.5	12.6	13.7	1.34	-57.7	52.7

^aBulk polymerization was conducted at 110°C for 24 h. The polymerization applied Sn(Oct)₂ as the catalyst. ^bMethylene of benzyl alcohol served as a reference to calculate DP of 1-PCL: ; methylene of the terminal group CH₂OH served as a reference to calculate DP of 4-PCL: . ^cMn was determined by ¹H NMR and the deuterium solvent was CDCl₃. ^dMn and PDI were determined by GPC using polystyrene as calibration. THF was in the mobile phase. ^eThermal analysis was measured by DSC with a heating rate of 10°C/min under N₂ flow.