Self-micellizing solid dispersion of thymoquinone with enhanced biopharmaceutical and nephroprotective effects

Figures & data

Figure 1. Apparent solubility of TQM in the aqueous solution of soluplus^®, kolliphor^® P188 and, kolliphor^® P407 at various concentrations (5–25 mg/mL). Data presented as mean ± S.D. (n=3).

Table 1. Apparent solubility data of binary complexes of TQM with different polymers.

Complex/Parameter	S0 (g/mol)	Slope	R^2	Ks (M^−1)	C.E.
TQM-Soluplus^®	0.001428	0.0099	0.9831	1161.5	0.010
TQM-Kolliphor^® P188		0.0037	0.9735	427.1	0.004
TQM- Kolliphor^® P407		0.01	0.8441	1149.4	0.010

S₀: solubility of TQM in water; Ks: stability constant; and C.E.: complexation efficiency.

Table 2. Dissolution properties of TQM samples.

	Composition of SMSD-TQM (w/w %)		Initial dissolution rate (hr^-1)	% dissolved at 60 min
	TQM	Soluplus^®
Crystalline TQM	100	–	0.767 ± 0.03	45.2 ± 4.6
SMSD-TQM/5	5	95	1.128 ± 0.10	73.9 ± 6.2
SMSD-TQM/10	10	90	1.062 ± 0.21	89.3 ± 6.6
SMSD-TQM/15	15	85	0.770 ± 0.14	66.7 ± 12.6

TQM: crystalline thymoquinone; SMSD-TQM: self-micellizing solid dispersion of thymoquinone.

^aInitial dissolution rate in water.

^bDissolved amount of TQM in water solution at 60 min. Data presented as mean ± S.D. (n=3).

Figure 2. Crystallinity assessment of TQM samples using (A) XRPD and (B) DSC. (I) Crystalline TQM, (II) SMSD-TQM/RVD, and (III) SMSD-TQM/FD.

Figure 3. Microscopic images observed by polarized light microscope (A) and scanning electron microscope (B). (I) Crystalline TQM, (II) SMSD-TQM/RVD, and (III) SMSD-TQM/FD. Each black and white bar represents 100 μm and 50 μm, respectively.

Figure 4. Micelle forming potency of TQM samples dispersed in water. (A) Micelle size distribution of SMSD-TQM spread in distilled water as determined by DLS analysis: the red line represents the particle size distribution of SMSD-TQM/FD; and the green line represents the particle size distribution of SMSD-TQM/RVD. (B) TEM image of SMSD-TQM dispersed in distilled water. Bar represents 500 nm.

Figure 5. Dissolution tests of TQM samples in water. ○, crystalline TQM; △, SMSD-TQM/RVD; ▽, PM of TQM and soluplus^®, and ◇, SMSD-TQM/FD. Data represent the mean ± S.D. of 3 experiments.

Figure 6. Drug-polymer interaction studies of TQM samples using FT-IR. Baseline-corrected and normalized IR data of TQM samples in the spectral wavenumber region from (A) 4,000–600 cm⁻¹ and (B) 1,800–1,300 cm⁻¹. (I) SMSD-TQM/FD, (II) SMSD-TQM/RVD (III) Soluplus^®, and (IV) crystalline TQM.

Figure 7. Plasma concentration-time profile of TQM after oral administration of TQM samples in rats. ○, crystalline TQM (10 mg/kg, p.o.), □, SMSD-TQM/RVD (5 mg-TQM/kg, p.o.), and △, SMSD-TQM/FD (5 mg-TQM/kg, p.o.). data represent mean ± S.E. of 6 experiments.

Table 3. Pharmacokinetic parameters of TQM samples following oral administration to rats.

Parameters	Crystalline TQM (10 mg/kg; p.o.)	SMSD-TQM/RVD (5 mg-TQM/kg; p.o.)	SMSD-TQM/FD (5 mg-TQM/kg; p.o.)
Cmax (ng/mL)	165.5 ± 23.3	298.2 ± 32.6	425.1 ± 11.2**
Dose normalized Cmax (ng/mL)	16.55 ± 2.33	59.64 ± 6.52	85.02 ± 2.23
Tmax (h)	0.41 ± 0.08	0.67 ± 0.16	0.41 ± 0.08
AUC0–6 (ng • h/mL)	488.1 ± 89.7	1,002.5 ± 122.3	1,049.3 ± 44.44*
AUC0–∞ (ng • h/mL)	554.6 ± 79.6	1,230.5 ± 184.3	1,349.9 ± 262.6*
Dose normalized AUC0–∞ (ng • h/mL)	55.46 ± 7.94	246.09 ± 36.87	269.98 ± 52.51
MRT (h)	2.25 ± 0.05	2.23 ± 0.03	2.08 ± 0.23
Vd (L)	0.061 ± 0.02	0.028 ± 0.002	0.025 ± 0.005
t1/2 (h)	2.3 ± 0.36	2.34 ± 0.16	2.38 ± 0.96
Ke (h^-1)	0.31 ± 0.04	0.29 ± 0.02	0.37 ± 0.10
Absolute BA (%)	2.8	12.5	13.7
Relative BA (%)	100	443	487

C_max: maximum concentration; T_max: time to maximum concentration; AUC_0–6: area under the curve of blood concentration vs. time from 0 h to 6 h; AUC_0–∞: area under the curve of blood concentration vs. time from 0 h to infinity; MRT: mean residence time; t_1/2: elimination half-life; and K_e: elimination rate constant. Data represents mean ± S.E. of 6 experiments. * P < 0.05, and ** P < 0.001 with respect to orally-dosed crystalline TQM.

Figure 8. Nephrotoxic potential in a rat nephropathy model induced by cisplatin (6 mg/kg, ip). (A) plasma creatinine, (B) BUN, (C) NO, (D) SOD, (E) GSH, and (F) AOPP levels in rats with orally dosed crystalline TQM and SMSD-TQM (10 mg/kg, 4 days). **, P < 0.01; ***, P < 0.001 with respect to cisplatin-treated rats; ##, P < 0.01; ###, P < 0.001, TQM vs. SMSD-TQM. Data represent mean ± S.E. of 4 experiments.

Figure 9. Histological features of liver sections after cisplatin challenge with or without oral administration of crystalline TQM (10 mg/kg, p.o.) or SMSD-TQM (10 mg-TQM/kg, p.o.). (A) Rats treated with saline, (B) cisplatin-treated rats, (C) cisplatin-treated rats with crystalline TQM, (D) cisplatin-treated rats with SMSD-TQM/RVD and (E) cisplatin-treated rats with SMSD-TQM/FD. Each bar represents 50 µm.

Data availability statement

Upon a reasonable request, the corresponding author will provide access to the data supporting this study.