The influence of mPEG-PCL and mPEG-PLGA on encapsulation efficiency and drug-loading of SN-38 NPs

Figures & data

Figure 1. Morphological characteristics of SN-38 NPs containing mPEG2000-PCL1140 (A), mPEG2000-PCL2000 (B), mPEG2000-PCL4000 (C), mPEG2000-PCL5300 (D), mPEG2000-PCL6000 (E), mPEG2000-PCL8000 (F), mPEG5000-PCL1000 (G), mPEG5000-PCL2000 (H), mPEG5000-PCL4000 (I), mPEG5000-PCL5000 (J), mPEG5000-PCL10000 (K), mPEG5000-PCL15000 (L), mPEG2000-PLGA2000 (M), mPEG2000-PLGA4000 (N), mPEG2000-PLGA5000 (O), mPEG5000-PLGA1000 (P), mPEG5000-PLGA2000 (Q), mPEG5000-PLGA4000 (R), mPEG5000-PLGA5000 (S), mPEG5000-PLGA10000 (T), and mPEG5000-PLGA20000 (U), respectively.

Figure 2. Profiles of encapsulation efficiency and drug-loading of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG2000-PCLs.

Table 1. Physicochemical characteristics of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG2000-PCLs.

Sample	Mean diameter (nm) ± SD	PdI	Zeta potential (mV) ± SD	Encapsulation efficiency (%) ± SD	Drug-loading (%) ± SD
SP2C1	162.2 ± 17.3	0.317	−9.22 ± 0.13	31.87 ± 4.98	1.39 ± 0.17
SP2C2	161.7 ± 12.5	0.395	−8.92 ± 0.72	53.14 ± 3.65	2.14 ± 0.13
SP2C4	156.2 ± 9.2	0.374	−12.57 ± 1.82	65.58 ± 6.15	2.56 ± 0.38
SP2C5	166.3 ± 10.9	0.242	−3.30 ± 0.48	83.21 ± 1.72	3.36 ± 0.13
SP2C6	177.9 ± 7.7	0.289	−3.74 ± 1.26	75.93 ± 1.84	3.37 ± 0.11
SP2C8	211.2 ± 14.8	0.262	−2.21 ± 1.00	66.28 ± 2.32	2.86 ± 0.08
SP2C10	248.5 ± 27.5	0.356	−2.29 ± 0.86	6.42 ± 2.66	0.19 ± 0.07

Figure 3. Profiles of encapsulation efficiency and drug-loading of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG5000-PCLs.

Table 2. Physicochemical characteristics of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG5000-PCLs.

Sample	Mean diameter (nm) ± SD	PdI	Zeta potential (mV) ± SD	Encapsulation efficiency (%) ± SD	Drug-loading (%) ± SD
SP5C1	252.2 ± 7.5	0.313	−5.64 ± 0.89	41.89 ± 3.24	1.70 ± 0.14
SP5C2	177.2 ± 20.2	0.247	−9.24 ± 0.23	61.54 ± 2.56	2.41 ± 0.10
SP5C4	194.8 ± 15.8	0.394	−5.47 ± 0.15	68.27 ± 0.49	2.69 ± 0.15
SP5C5	178.5 ± 17.1	0.322	−5.25 ± 0.73	70.48 ± 2.96	2.41 ± 0.18
SP5C10	161.2 ± 3.6	0.265	−5.30 ± 0.79	80.71 ± 1.24	3.13 ± 0.17
SP5C15	192.7 ± 11.0	0.300	−4.88 ± 0.24	76.83 ± 2.24	3.19 ± 0.12
SP5C20	234.9 ± 5.0	0.327	−4.13 ± 0.60	6.69 ± 0.82	0.28 ± 0.04
SP5C45	346.1 ± 74.6	0.414	−10.45 ± 0.82	2.70 ± 2.64	0.10 ± 0.10

Table 3. CMC values of different copolymers.

mPEG-PCL	CMC (mg/mL)	mPEG-PLGA	CMC (mg/mL)
mPEG2000-PCL2000	0.000805	mPEG2000-PLGA4000	0.000808
mPEG2000-PCL5300	0.000732	mPEG2000-PLGA5000	0.000805
mPEG2000-PCL8000	0.000715	mPEG2000-PLGA9000	0.000757
mPEG5000-PCL4000	0.000794	mPEG5000-PLGA4000	0.000992
mPEG5000-PCL10000	0.000754	mPEG5000-PLGA10000	0.000943
mPEG5000-PCL20000	0.000702	mPEG5000-PLGA20000	0.000838

Table 4. HLB values of different copolymers.

mPEG-PCL	HLB	mPEG-PLGA	HLB
mPEG2000-PCL1140	12.7	mPEG2000-PLGA1000	13.3
mPEG2000-PCL2000	10.0	mPEG2000-PLGA2000	10.0
mPEG2000-PCL4000	6.7	mPEG2000-PLGA4000	6.7
mPEG2000-PCL5300	5.5	mPEG2000-PLGA5000	5.7
mPEG2000-PCL6000	5.0	mPEG2000-PLGA9000	3.6
mPEG2000-PCL8000	4.0	mPEG2000-PLGA18000	2.0
mPEG2000-PCL10000	3.3	mPEG5000-PLGA1000	16.7
mPEG5000-PCL1000	16.7	mPEG5000-PLGA2000	14.3
mPEG5000-PCL2000	14.3	mPEG5000-PLGA4000	11.1
mPEG5000-PCL4000	11.1	mPEG5000-PLGA5000	10.0
mPEG5000-PCL5000	10.0	mPEG5000-PLGA10000	6.7
mPEG5000-PCL10000	6.7	mPEG5000-PLGA20000	4.0
mPEG5000-PCL15000	5.0
mPEG5000-PCL20000	4.0
mPEG5000-PCL45000	2.0

Figure 4. Profiles of encapsulation efficiency and drug-loading of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG2000-PLGAs.

Table 5. Physicochemical characteristics of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG2000-PLGAs.

Sample	Mean diameter (nm) ± SD	PdI	Zeta potential (mV) ± SD	Encapsulation efficiency (%) ± SD	Drug-loading (%) ± SD
SP2G1	274.6 ± 1.7	0.289	−16.43 ± 4.90	4.80 ± 0.51	0.17 ± 0.03
SP2G2	173.1 ± 35.9	0.332	−10.93 ± 0.58	69.19 ± 0.71	2.59 ± 0.03
SP2G4	205.5 ± 22.2	0.244	−10.70 ± 0.30	68.49 ± 2.69	2.46 ± 0.10
SP2G5	184.4 ± 19.8	0.252	−12.53 ± 1.22	79.59 ± 2.26	3.09 ± 0.09
SP2G9	232.2 ± 23.9	0.240	−14.63 ± 0.81	12.82 ± 3.34	0.50 ± 0.10
SP2G18	–	–	–	–	–

Figure 5. Profiles of encapsulation efficiency and drug-loading of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG5000-PLGAs.

Table 6. Physicochemical characteristics of SN-38-loaded nanoparticles with different hydrophobic segments of mPEG5000-PLGAs.

Sample	Mean diameter (nm) ± SD	PdI	Zeta potential (mV) ± SD	Encapsulation efficiency (%) ± SD	Drug-loading (%) ± SD
SP5G1	134.8 ± 15.6	0.204	−9.63 ± 0.46	47.63 ± 0.23	1.58 ± 0.25
SP5G2	230.1 ± 18.0	0.229	−9.61 ± 0.73	70.77 ± 1.39	2.94 ± 0.17
SP5G4	164.5 ± 13.7	0.326	−9.66 ± 0.53	49.29 ± 4.64	1.80 ± 0.16
SP5G5	171.4 ± 26.6	0.227	−11.35 ± 1.87	67.96 ± 2.43	2.56 ± 0.12
SP5G10	200.6 ± 4.6	0.233	−4.27 ± 0.80	76.54 ± 2.00	2.93 ± 0.08
SP5G20	272.0 ± 18.4	0.275	−12.1 ± 0.30	52.19 ± 2.57	2.15 ± 0.15

Figure 6. In vitro release curve of SN-38-loaded nanoparticles with different molecular weight of hydrophobic segments (mPEG2000-PCL1140, mPEG2000-PCL2000, mPEG2000-PCL4000, mPEG2000-PCL5300, mPEG2000-PCL6000, and mPEG2000-PCL8000).

Figure 7. In vitro release curve of SN-38-loaded nanoparticles with different molecular weight of hydrophobic segments (mPEG5000-PCL1000, mPEG5000-PCL2000, mPEG5000-PCL4000, mPEG5000-PCL5000, mPEG5000-PCL10000, and mPEG5000-PCL15000).

Figure 8. In vitro release curve of SN-38-loaded nanoparticles with different molecular weight of hydrophobic segments (mPEG2000-PLGA2000, mPEG2000-PLGA4000, and mPEG2000-PLGA5000).

Figure 9. In vitro release curve of SN-38-loaded nanoparticles with different molecular weight of hydrophobic segments (mPEG5000-PLGA1000, mPEG5000-PLGA2000, mPEG5000-PLGA4000, mPEG5000-PLGA5000, mPEG5000-PLGA10000, and mPEG5000-PLGA20000).

Figure 10. pH-dependent equilibrium of SN-38.