An optimized probucol microencapsulated formulation integrating a secondary bile acid (deoxycholic acid) as a permeation enhancer

Figures & data

Figure 1 Optical microscopy of PB-SA and PB-DCA-SA microcapsules.

Notes: (A) PB-SA microcapsules. (B) PB-DCA-SA microcapsules.
Abbreviations: DCA, deoxycholic acid; L1, outer membrane thickness; L2, horizontal diameter; L3, vertical diameter; PB, probucol; SA, sodium alginate.

Figure 2 Scanning electron micrographs of a PB-SA microcapsule.

Notes: (A) 200 μm scale. (B) Surface morphology at 10 μm scale. (C) 200 nm scale. (D) 1 μm scale.
Abbreviations: PB, probucol; SA, sodium alginate.

Figure 3 Scanning electron micrographs of a PB-DCA-SA microcapsule.

Notes: (A) 100 μm scale. (B–D) Surface morphology from different angles at 10 μm scale.
Abbreviations: DCA, deoxycholic acid; PB, probucol; SA, sodium alginate.

Figure 4 Energy dispersive X-ray spectra of PB-SA microcapsules.

Notes: (A and B) PB deposition (indicated by 1) with corresponding analysis. (C and D) Surface composition (indicated by 2) with corresponding analysis.
Abbreviations: PB, probucol; SA, sodium alginate.

Figure 5 Energy dispersive X-ray spectra of PB-DCA-SA microcapsules.

Notes: (A and B) PB deposition (indicated by 1) with corresponding analysis. (C and D) Surface composition (indicated by 2) with corresponding analysis.
Abbreviations: DCA, deoxycholic acid; PB, probucol; SA, sodium alginate.

Table 1 Viscosities and related parameters of both microencapsulated formulations

Formula code	Set speed	rpm	Viscosity (mPa·s)	Shear rate (s^−1)	Torque (mNm)	Shear stress (Pa)
PB-SA	1	20	UD	23.9±1	UD	UD
	2	35	UD	42.2±2	UD	UD
	3	61	UD	74.5±2	0.08±0.02	UD
	4	107	25±0.2	125.1±2	0.11±0.01	3.2±0.01
	5	187	20±0.1	222.2±3	0.17±0.03	4.5±0.01
	6	327	15±0.1	385.7±4	0.21±0.01	5.7±0.03
	7	572	10±0.3	681.8±8	0.26±0.03	6.9±0.02
	8	1,000	9±0.1	1,194±10	0.40±0.01	10.9±0.01
PB-DCA-SA	1	20	UD	28±1	UD	UD
	2	35	UD	42.1±2	UD	UD
	3	61	UD	74.4±3	UD	UD
	4	107	UD	124.9±5	UD	UD
	5	187	UD	221.9±7	0.11±0.01	UD
	6	327	12±0.2	385.0±5	0.16±0.03	4.5±0.03
	7	572	11±0.1	681±10	0.27±0.02	7.2±0.01
	8	1,000	10±0.2	1,195±12	0.43±0.01	11.7±0.02

Note: n=3. Data are described as mean ± SD.

Abbreviations: DCA, deoxycholic acid; PB, probucol; SA, sodium alginate; SD, standard deviation; UD, undetected (below the instrument limit of detection).

Figure 6 Differential scanning calorimetric thermograms of the individual powders, mixed powder containing all the ingredients, and microcapsules.

Notes: (A) PB powder. (B) DCA powder. (C) SA powder. (D) PB-DCA-SA powder. (E) PB-SA microcapsules. (F) PB-DCA-SA microcapsules.
Abbreviations: DCA, deoxycholic acid; PB, probucol; SA, sodium alginate.

Figure 7 Fourier transform infrared spectra of the individual powders, mixed powder containing all the ingredients, and microcapsules.

Notes: (A) PB powder. (B) DCA powder. (C) SA powder. (D) PB-DCA-SA powder. (E) PB-SA microcapsules. (F) PB-DCA-SA microcapsules.
Abbreviations: DCA, deoxycholic acid; PB, probucol; T, transmitted light; SA, sodium alginate.