Ordered nanoporous silica as carriers for improved delivery of water insoluble drugs: a comparative study between three dimensional and two dimensional macroporous silica

Figures & data

Figure 1 Schematic illustration of the pore structures of (A) 2D mesoporous silica, (B) 3DOM silica, and (C) molecular structure of indomethacin.

Notes: 2D mesoporous silica contains cylindrical mesopores arranged parallel to each other, while 3DOM silica contains spherical macropores connected by windows.

Abbreviation: 3DOM, three dimensional ordered macroporous.

Figure 2 SEM images of (A) M-1, (B) M-2, (C) SBA-15, and (D) MCM-41.

Abbreviations: M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; SEM, scanning electron microscopy.

Figure 3 TEM images of (A) M-1, (B) M-2, (C) SBA-15, and (D) MCM-41.

Abbreviations: M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; TEM, transmission electron microscopy.

Figure 4 SEM images of (A) IMC-loaded M-1, (B) IMC-loaded M-2, (C) IMC-loaded SBA-15, and (D) IMC-loaded MCM-41.

Abbreviations: IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; SEM, scanning electron microscopy.

Table 1 Detailed textural parameters of samples by N₂ adsorption measurements

Sample	SBET (m^2/g)	Vt (cm^3/g)	WBJH (nm)
M1	303.8	0.419	\
IMC-M1	176.9	0.206	\
M2	130.2	0.101	\
IMC-M2	59.1	0.062	\
SBA-15	530.0	0.883	8.42
IMC-SBA	231.6	0.435	6.76
MCM-41	996.2	0.704	3.9
IMC-MCM	387.0	0.287	N/A

Abbreviations: BJH, Barrett–Joyner–Halenda; IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; S_BET, BET surface area; Vt, total pore volume calculated as the amount of nitrogen adsorbed at the relative pressure of 0.98; W_BJH, average pore diameter was calculated using the BJH model.

Figure 5 The N₂ adsorption-desorption isotherms of (A) M1 and M1-IMC, (B) M2 and M2-IMC, (C) SBA-15 and SBA-IMC and (D) MCM-41 and MCM-IMC.

Abbreviations: M1-IMC, IMC-loaded M1; M2-IMC, IMC-loaded M2; SBA-IMC, IMC-loaded SBA-15; MCM-IMC, IMC-loaded MCM-41; IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; Ps, measured pressure; Po, saturated vapor pressure of N₂; SBA, Santa Barbara Amorphous; STP, standard temperature and pressure.

Figure 6 XRD patterns for raw IMC powders (insert) and IMC-loaded nanoporous silica samples.

Abbreviations: au, arbitrary unit; IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; XRD, X-ray diffraction.

Figure 7 DSC thermograms for pure IMC powders and IMC-loaded nanoporous silica samples.

Abbreviations: DSC, differential scanning calorimetry; IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous.

Figure 8 In vitro dissolution profiles for pure IMC powders and IMC-loaded nanoporous silica samples.

Note: Each data point represents the mean ± standard deviation of three determinations.

Abbreviations: IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; min, minutes; SBA, Santa Barbara Amorphous.

Figure 9 (A) XRD curves and (B) DSC patterns of physical stability of IMC-loaded porous silica systems after storage at a relative humidity of 75% and 40°C.

Abbreviations: au, arbitrary unit; DSC, differential scanning calorimetry; IMC, indomethacin; M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous; XRD, X-ray diffraction.

Figure 10 Effect of nanoporous silica on cell viability of Caco-2 cells by (A) MTT and (B) CCK-8 assays.

Notes: Experiments were carried out in triplicate and error bars indicate standard deviation; *P<0.05.

Abbreviations: CCK, Cell Counting Kit; M, macroporous; MCM, Mobil Composition of Matter; MTT, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; SBA, Santa Barbara Amorphous.

Figure 11 Phase contrast inverted microscope image of Caco-2 cells untreated (control) and treated with various silica carriers at the same concentration. (A) Control, (B) M1, (C) M2, (D) SBA-15, and (E) MCM-41.

Abbreviations: M, macroporous; MCM, Mobil Composition of Matter; SBA, Santa Barbara Amorphous.

Figure S1 The intensity-weighted particle size distributions for (A) PMMA and (B) PS microspheres based on dynamic light scattering.

Abbreviations: PMMA, poly-(methyl methacrylate); PS, polystyrene; Intens-WT, intensity-weighted; REL, relative; Diam, diameter.

Figure S2 SEM images for colloidal templates of (A) PMMA and (B) PS spheres.

Abbreviations: PMMA, poly-(methyl methacrylate); PS, polystyrene; SEM, scanning electron microscopy.

Figure S3 SEM image of crude IMC powders.

Abbreviations: IMC, indomethacin; SEM, scanning electron microscopy.

Table S1 Reaction conditions for the synthesis of microspheres by soap-free emulsion polymerization

Microsphere	KPS	Monomer	Polymerization time (hours)	Diameter (nm)
PMMA	10 mL	30 mL	2	280
PS	20 mL	20 mL	24	680

Abbreviations: KPS, potassium persulfate; PMMA, poly-(methyl methacrylate); PS, polystyrene.