Preparation of Biodegradable Polycaprolactone/Poly (ethylene glycol)/Polycaprolactone (PCEC) Nanoparticles

Figures & data

DIAG. 1.  Synthesis scheme of the PCEC copolymer.

TABLE 1  Preparing parameters for PCEC nanoparticles

Sample	Vouter aqueous (ml)	CPVA (%)	CPCEC (%)	Vinner aqueous (ml)	VSolvent (ml)	Theoretical drug loading (%)
N1	100	4	2.5	1	DMSO: 5	10
N2	100	4	2.5	0.75	DMSO: 5	10
N3	100	4	2.5	0.5	DMSO: 5	10
R2	100	4	2.5	1	DMSO: 2.5+CH2Cl2: 2.5	10
R3	100	4	2.5	1	CH2Cl2: 5	10
Z2	100	4	2.5	1	DMSO: 5	5
Z3	100	4	2.5	1	DMSO: 5	15

V = volume, C = concentration.

FIG. 1.  FTIR spectra of the PCEC copolymer.

FIG. 2.  ¹H-NMR spectrum of the PCEC copolymer.

TABLE 2  Basic data of PCEC nanoparticles prepared in mean values (n = 3)

Number	D (nm)	PDI	DL (%)	EE (%)	Burst effect (%) (Q in 0.5 hr)
N1	598.18	0.105	4.95	49.5	61.7
N2	512.37	0.063	4.02	40.2	40.8
N3	431.58	0.043	2.18	21.8	46.4
R2	1044.97	0.111	1.75	17.5	62.4
R3	5532.01 (67%), 2712.84 (33%)	0.383	1.67	16.7	53.5
Z2	468.87	0.041	2.15	42.99	45.1
Z3	452.13	0.047	5.28	35.21	87.8

D = the average diameter; PDI = polydispersity index; DL = drug loading; EE = encapsulation efficiency; Q = accumulative release weight.

FIG. 3.  SEM morphology of various nanoparticles prepared by different organic solvents (with different mixing ratio of DMSO and CH₂Cl₂). (A) Organic phase is DMSO, degradation Time T = 0d (A1), T = 3 d (A2), and T = 5 d (A3). (B) Organic phase is DMSO + CH₂Cl₂, degradation Time T = 0d (B1), T = 3d (B2), and T = 5d (B3). (C) Organic phase is CH₂Cl₂ only, degradation Time T = 0d (C1), T = 3d(C2), and T = 5d (C3).

FIG. 4.  Release profiles of BSA nanoparticles in phosphate buffer at 37°C and pH 7.4 in 120 hr. (a) Effect of inner aqueous phase on BSA release profiles of PCEC nanoparticles: release profiles of N1, N2, and N3. (b) Effect of organic solvent on BSA release profiles of PCEC nanoparticles: release profiles of N1, R2, and R3. (c) Effect of drug loading on BSA release profiles of PCEC nanoparticles: release profiles of N1, Z2, and Z3.

FIG. 5.  Release profiles of BSA nanoparticles in phosphate buffer at 37°C and pH 7.4 in 4 hr. (a) Effect of inner aqueous phase on BSA release profiles of PCEC nanoparticles: release profiles of N1, N2, and N3. (b) Effect of organic solvent on BSA release profiles of PCEC nanoparticles: Release profiles of N1, R2 and R3. (c) Release profiles of N1, Z2, and Z3.

FIG. 6.  Typical SDS-PAGE results of BSA IN vitro release. Band A = Original BSA; band B = BSA released from N1; band C = BSA released from R2.