Impact of Core-Forming Segment Structure on Drug Loading in Biodegradable Polymeric Micelles Using PEG-b-Poly(lactide-co-depsipeptide) Block Copolymers

Table 1

Results of characterization of copolymers.

Code	w ^a [mol%]	Mn^b (×10^−4)	Mn^c (×10^−4)	Mw/Mn^c	DP^b,d	x ^b,e [mol%]	𝑋𝑐^f [%]
b-PLLA	—	1.15	0.90	1.27	45	—	35
b-PDLLA	—	1.15	0.81	1.29	45	—	—
b-PLGL𝟐𝟎	20	1.09	0.92	1.35	40	20	0
b-PLGL𝟑𝟕	40	1.13	1.03	1.35	40	37	0
b-PLGL𝟒𝟗	50	1.11	0.90	1.38	39	49	0
b-PLGL𝟓𝟗	60	1.24	1.11	1.42	46	59	0
b-PLGL𝟕𝟓	75	1.17	1.02	1.39	41	75	0
b-PLGF𝟐𝟒	24	1.06	0.91	1.38	34	24	0
b-PLGF𝟒𝟗	50	1.11	0.91	1.38	35	49	0
b-PLGF𝟕𝟑	68	1.10	0.89	1.42	32	73	0

aMole fraction of depsipeptide units in feed. ^bEstimated by ¹H NMR (solvent: CDCl₃). ^cEstimated by SEC (eluent: DMF; standard: PEG). ^dDegree of polymerization of sum of lactide and depsipeptide units. ^ex: mole fraction of depsipeptide units in a hydrophobic segment of diblock copolymers. ^f𝑋_𝑐: crystallinity determined by differential scanning calorimetry (DSC). 𝑋_𝑐 = (Δ𝐻_𝑚+Δ𝐻_𝑐)/Δ𝐻_𝑚,theory (Δ𝐻_𝑚,theory = −93.7 J/g).