The role of the bile acid chenodeoxycholic acid in the targeted oral delivery of the anti-diabetic drug gliclazide, and its applications in type 1 diabetes

Figures & data

Figure 1. Light microscope images of (a) G-SA microcapsule (b) G-CDCA-SA microcapsule.

Figure 2. Scanning electron micrographs of the G-SA microcapsule (a) surface morphology at 100 μm scale (b) surface morphology at 50 μm scale (c) surface morphology at 10 μm scale (d) surface morphology at 2 μm scale.

Figure 3. Scanning electron micrographs of G-CDCA-SA microcapsule (a) surface morphology at 100 μm scale (b) surface morphology at 50 μm scale (c) surface morphology at 10 μm scale (d) surface morphology at 2 μm scale.

Figure 4. Energy dispersive X-ray spectra of G-SA microcapsules at four locations, with the corresponding analyses (1, 2, 3, and 4) respectively.

Figure 5. Energy dispersive X-ray spectra of G-CDCA-SA microcapsules at four locations, with the corresponding analyses (1, 2, 3, and 4) respectively.

Table I. Rheological parameters of G-SA and G-CDCA-SA (n = 3). Values are expressed as mean ± SD. UD: undetected.

Formula Code	Set speed	RPM	Viscosity (mPas)	Shear rate (s-1)	Torque (mNm)	Shear stress (Pa)
G-SA	1	20	UD	24.5 ± 2	UD	UD
	2	35	UD	40.7 ± 2	UD	UD
	3	61	UD	70.6 ± 3	UD	UD
	4	107	UD	122 ± 5	0.032 ± 0.002	UD
	5	187	22 ± 0.6	222 ± 8	0.048 ± 0.004	1.5 ± 0.1
	6	327	14 ± 0.3	381 ± 10	0.11 ± 0.01	2.0 ± 0.2
	7	572	4 ± 0.1	679 ± 15	0.10 ± 0.01	3.8 ± 0.2
	8	1000	6 ± 0.2	1190 ± 18	0.26 ± 0.02	6.7 ± 0.5
G-CDCA-SA	1	20	UD	UD	UD	UD
	2	35	UD	UD	UD	UD
	3	61	UD	66 ± 15	UD	UD
	4	107	18 ± 0.8	87 ± 13	UD	UD
	5	187	10 ± 0.4	220 ± 30	0.051 ± 0.01	1.8 ± 0.8
	6	327	7 ± 0.4	381 ± 9	0.11 ± 0.01	3.5 ± 0.2
	7	572	6 ± 0.3	678 ± 12	0.15 ± 0.04	5.3 ± 0.2
	8	1000	5 ± 0.3	1192 ± 17	0.32 ± 0.06	7.0 ± 0.4

Figure 6. Thermal scanning of (a) CDCA powder (b) G powder (c) G-CDCA-SA microcapsules (d) G-SA microcapsules (e) G-CDCA-SA powder (f) SA powder.

Figure 7. FTIR spectra of (a) CDCA powder (b) G powder (c) G-CDCA-SA microcapsules (d) G-SA microcapsules (e) G-CDCA-SA powder (f) SA powder.

Table II. Drug contents, production yield, microencapsulation efficiency, Zeta potential, and mean particle size (n = 3), and data are expressed as average ± SD). **p < 0.01.

Formulation Code	Formula Composition	Drug Content (%) ± SD	Production Yield (%) ± SD	Encapsulation Efficiency (%) ± SD	Zeta-potential (mV) ± SD	Mean particle size (μm) ± SD
G-SA	Gliclazide-Sodium alginate microcapsules	6 ± 0.2	80 ± 4	92 ± 6	− 70 ± 3	915 ± 10
G-CDCA-SA	Gliclazide-Chenodeoxycholic acid-Sodium alginate microcapsules	3 ± 0.4**	82 ± 6	87 ± 5	− 45 ± 3**	925 ± 55

Figure 8. G release from the microcapsules at different pH values (a) 1.5 and 3.0, and (b) 6.0 and 7.8. Data are mean ± SD, n = 3.

Figure 9. Swelling (at 25°C) of G-SA and G-CDCA-SA microcapsules at pH 1.5 and 3.0 (a) and pH 6.0 and 7.8 (b). Data are average ± SD, n = 3.

Figure 10. Swelling (at 37°C) of G-SA and G-CDCA-SA microcapsules at pH 1.5 and 3.0 (a) and pH 6.0 and 7.8 (b). Data are average ± SD, n = 3.

Figure 11. Mechanical Strength Index for G-SA and G-CDCA-SA microcapsules. Data are average ± SD, n = 3.