Dual-targeting delivery system for bone cancer: synthesis and preliminary biological evaluation

Figures & data

Figure 1.  Structure of the fully protected RGD, D₆, RGD₇ (1–3).

Figure 2.  (A) Percentage of conjugates bound to HAP at 1 and 24 h. (B) Change of percent conjugates T1a, T2a, and T3a bound to HAP. Error bars represent the mean and SD of three independent experiments.

Table 1.  Solubility of T1a-b, T2a-b, T3a-b in water (pH=7).

Compound	MW	Water solubility C (mg/mL)	5-FU concentration (μmol/mL)
5-FU	130.08	10.51 ± 0.24	80.80 ± 1.85
T1a	516.44	50.82 ± 0.03	98.46 ± 0.23
T1b	588.50	60.24 ± 0.04	102.42 ± 0.31
T2a	878.64	129.54 ± 0.16	147.43 ± 1.23
T2b	950.70	142.02 ± 0.19	149.38 ± 1.46
T3a	1206.96	191.97 ± 0.40	159.27 ± 3.08
T3b	1279.02	209.41 ± 0.46	163.81 ± 3.15

5-FU, 5-fluorouracil.

Figure 3.  Release of 5-FU from compound T3a (A) and compound T3b (B) in physiological conditions. Error bars represented the mean and standard deviation of three independent experiments. 5-FU, 5-fluorouracil.

Scheme 1.  The synthesis of compound 4–6. Reagents and Conditions: (a) BrCH₂COOH, KOH,40°C; (b) i, HCHO, 60°C; ii, PhCH₂OOCCH₂CH₂COOH, CH₃CN, DCC, DMAP, r.t.; (c) 10% Pd/ C, CH₃OH, r.t. DCC, dicyclohexylcarbodiimide; DMAP, dimethylamino-pyridine.

Scheme 2.  The synthesis of compound 3. Reagents and Conditions: (a) i, TFA, CH₂Cl₂, r.t.; ii, Boc-Asp(OBzl)-OH, IBCF, NMM, THF; (b) i, TFA, CH₂Cl₂,r.t.; ii, Boc-Gly-OH, IBCF, NMM, THF; (c) i, TFA, CH₂Cl₂,r.t.; ii, Boc-Arg(NO₂)-OH, IBCF, NMM, THF. IBCF, isobutyl chloroformate; NMM, N-methyl-morpholine; TFA, trifluoroacetic acid.

Scheme 3.  The synthesis of compounds T1a-b, T2a-b, T3a-b. Reagents and Conditions: (a) i, TFA, CH₂Cl₂,r.t.; ii, 4, IBCF, NMM, THF; iii, 10% Pd/ C, CH₃OH, r.t.; (b) i, TFA, CH₂Cl₂,r.t.; ii, 6, IBCF, NMM, THF; iii, 10% Pd/ C, CH₃OH, r.t. IBCF, isobutyl chloroformate; NMM, N-methyl-morpholine; TFA, trifluoroacetic acid.

Table 2.  Pharmacokinetic parameters of 5-FU and 5-FU-oligopeptides conjugate T1a, T2a, and T3a in rats.

	AUC (mg·h/L)	T1/2 (h)	V1/F (L/kg)	Cmax (mg/mL)	MRT
5-Fu	10.21 ± 5.01	0.77 ± 0.25	30.34 ± 4.31	20.32 ± 2.11	2.34 ± 0.77
T1a	20.33 ± 2.33	2.12 ± 0.56	20.87 ± 0.23	10.32 ± 0.77	5.89 ± 1.00
T2a	40.89 ± 8.12	7.92 ± 1.02	29.33 ± 1.02	34.11 ± 0.87	7.98 ± 0.79
T3a	70.92 ± 1.98	8.91 ± 0.88	49.98 ± 2.76	56.12 ± 1.32	10.22 ± 0.87

Data are represented as mean ± SD.

5-FU, 5-fluorouracil; AUC, area under (the concentration time) curve; C_max, maximum concentration; MRT, mean retention time; T_1/2, biological halflife; V1/F, apparent volume of distribution.

Figure 4.  The biodistribution of the T1b, T2b, T3b, and naked 5-FU. The biodistribution was analyzed at (A) 2 h and (B) 12 h after oral administration. Error bars represented the mean and standard deviation of three independent experiments. N.D. cannot be detected.