In vitro and in vivo delivery of gliclazide loaded mPEG-PCL micelles and its kinetic release and solubility study

Figures & data

Figure 1. (a) Schematic synthesis route of mPEG-PCL copolymer, (b) ¹H-NMR spectrum of mPEG-PCL copolymer, and (c) GPC curve of copolymer P5.

Table 1. Molecular characterics of the synthesized copolymers.

Copolymer	PEG MW (g/mol)	CL/EG feed	Mn (Da)^a	Mw (Da)^a	PdI^b	Tm (°C)^c	DPPEG	DPPCL^d
P1	5000	0.5	8456	7123	1.18	50.09	136.36	30.27
P2	5000	1	9210	8237	1.11	53.21	136.36	36.88
P3	5000	2	11,963	9627	1.24	54.72	136.36	61.00
P4	5000	4	14,130	12,123	1.16	58.90	136.36	79.98
P5	5000	5	21,364	17,058	1.25	60.15	136.36	143.36

^aDetermined by GPC analysis using narrow molecular weight polystyrene standards.

^bM_w/M_n = Polydispersity index of the polymers (PdI) determined by GPC analysis.

^cCalculated from the first run of differential scanning calorimetry (DSC) as half of the extrapolated tangents.

^dDP: degree of polymerization.

Figure 2. AFM image of gliclazide loaded spherical core shell micelles.

Figure 3. Particle size distribution and zeta potential of gliclazide/mPEG-PCL and mPEG-PCL micelles. (a) particle size distribution and (b) zeta potential of gliclazide/mPEG-PCL micelles.

Figure 4. (a) Excitation spectra of pyrene in water for mPEG-PCL copolymer at various concentrationsand, (b) Intensity ratio I₃₉₂/I₃₇₃ of pyrene excitation spectra versus log C for mPEG-PCL copolymer.

Figure 5. Stability micelles.

Table 2. Characterisistic of micelles from the synthesized copolymers.

Micelles	CL/EG feed	EE (%)	DL (%)	Size (nm)	Zeta potential
M1	0.5	39.65	7.4	102.2	−11.7
M2	1	55.62	13.81	100.2	−
M3	2	64.87	15.23	100.7	−12.8
M4	4	74.8	17.14	83.22	−13.8
M5	5	94.11	21.05	83.12	−14.9

Table 3. Properties of gliclazide-loaded mPEG-PCL micelles.

Micelles	Gliclazide/copolymer mass ratio	EE (%)	DL (%)	Size (nm)	Zeta potential	PDI	Stability
M6	0	0	0	76.17	−13.1	0.186	Yes
M7	0.05	31.21	6.2	77.83	−12.5	0.190	Yes
M8	0.1	59.96	11.54	80.04	−15.4	0.210	Yes
M9	0.25	94.11	21.05	83.12	−14.9	0.230	Yes
M10	0.5	95.31	22.34	126.18	−12.8	0.246	Yes
M11	0.75	94.20	22.36	232.76	−14.3	0.215	No
M12	1	77.13	15.6	359.09	−11.7	0.304	No

Figure 6. FT-IR spectra of (a) gliclazide, (b) gliclazide/mPEG-PCL micelles, and (c) mPEG-PCL.

Figure 7. Differential scanning calorimetry (DSC) spectra of (a) gliclazide/mPEG-PCL micelles (b) gliclazide and (c) mPEG-PCL.

Figure 8. The release profiles of gliclazide from gliclazide/mPEG-PCL micelles in different release medias.

Figure 9. Solubility of gliclazide.

Figure 10. Effect of gliclazide and gliclazide/mPEG-PCL micelles on fasting blood sugar. All the values are expressed in mean ± SE (n = 6); *p < .05 compared to diabetic rat group; #p < .05 compared to gliclazide rat group.