Pre-Clinical Pharmacokinetics, Tissue Distribution and Physicochemical Studies of CLBQ14, a Novel Methionine Aminopeptidase Inhibitor for the Treatment of Infectious Diseases

Figures & data

Figure 1 Chemical Structure of (A) CLBQ14 and (B) Clioquinol. CLBQ14 and CQ are congeners of 8-hydroxyquinoline that differ from each other only by the halogen at position C_7.

Figure 2 Representative HPLC-UV Chromatograms for CLBQ14 and clioquinol (IS) in Solution.

Table 1 Intra- and Inter-Day Accuracy and Precision of HPLC-UV Method

Medium	Nominal Concentration (μg/mL)	Intra-Day (n=3)		Inter-Day (n=3)
		Accuracy (RE, %)	Precision (CV, %)	Accuracy (RE, %)	Precision (CV, %)
Solution	5	1.20	2.27	0.38	2.13
	20	1.07	2.70	0.53	4.50
	80	0.79	1.53	2.42	3.41

Note: Values ≤ 15% are considered acceptable.

Abbreviations: RE, Relative error; CV, Co-efficient of Variation.

Figure 3 Solubility of CLBQ14 in various solvents at room temperature. Mean of n = 3.

Table 2 Degradation Rate Constants and Half-Life of CLBQ14 at Various pH

pH	k (h^−1)	t1/2 (h)
1	0.047	14.8
2	0.046	15.1
3	0.049	14.1
4	0.056	12.3
5	0.058	12.0
6	0.080	8.7
7	0.109	6.3
8	0.098	7.1
9	0.080	7.0
10	0.106	6.5

Figure 4 Stability of CLBQ14 in various pH buffers at 37^oC. Data is expressed as mean of n = 3.

Figure 5 pH degradation rate profile for CLBQ14 in various USP buffers at 37 °C.

Table 3 Microsomal Stability and Predicted Plasma Clearance of CLBQ14

Species	Percent Remaining^a (%)	Clpredicted^b (L/h/kg)	Clpredicted^b (mL/min/kg)	Hepatic Blood Flow^c (mL/min/kg)
CD-1 Mouse	3.7 ± 1.36	3.2 ± 0.17	52.9 ± 3.56	90
SD Rat	26.8 ± 2.37	1.9 ± 0.17	31.4 ± 3.41	55
Cynomolgus monkey	17.5 ± 0.86	1.7 ± 0.02	28.2 ± 0.31	44
Human	35.5 ± 0.33	0.8 ± 0.12	13.9 ± 2.40	21

Notes:^aPercent remaining after incubation in liver microsomes for 1 hr. ^bPredicted hepatic clearance by well-stirred model. ^cHepatic blood flow obtained from literature.³⁰

Figure 6 Microsomal stability of CLBQ14 following incubation in liver microsomes from CD-1 mouse, SD rat, cynomolgus monkey and human at 37 °C for 60 mins. (A) Rate of CLBQ14 disappearance. (B) Percent CLBQ14 remaining after incubation. (Error bar = standard deviation).

Figure 7 CYP Phenotyping of CLBQ14 following incubation in rhCYPs at 37°C for 60 mins. (A) CLBQ14 disappearance. (B) Percent CLBQ14 remaining after incubation. (Error bar = standard deviation).

Table 4 CLBQ14 Pharmacokinetic Parameters Generated by Non-Compartmental Analysis

Pharmacokinetic Parameters (Units)	Mean Estimate ± SD			Description of Pharmacokinetic Parameters
	IV (2mg/kg)	PO (20 mg/kg)	SC (10 mg/kg)
C0/Cmax (mg/L)	2.4 ± 0.66	1.7 ± 0.65	0.9 ± 0.11	C0/Cmax = initial/maximum plasma concentration;
Tmax (h)	–	0.5 ± 0.00	1.2 ± 0.66	Tmax = time taken to reach maximum plasma concentration;
AUC0-∞ (mg/L/hr)	1.2 ± 0.06	4.5 ± 1.77	5.3 ± 0.50	AUC0-∞ = area under curve from time zero to infinity;
AUC0-∞/D (h*kg*mg/L/mg)	0.6 ± 0.03	0.2 ± 0.09	0.5 ± 0.05	AUC0-∞/D = dose normalized area under curve;
Cl (L/kg/hr)	1.67 ± 0.08	–	–	Cl = total body clearance;
Cl/F (L/kg/hr)	–	5.1 ± 2.54	1.9 ± 0.18	Cl/F = total body clearance for extravascular route;
VD (L/kg)	21.3 ± 0.57	–	–	VD = volume of distribution of central compartment;
VD/F (L/kg)	–	39.9 ± 16.3	15.1 ± 2.40	VD/F = volume of distribution for extravascular route;
T1/2 (hr)	8.9 ± 0.22	5.6 ± 0.62	5.6 ± 0.32	T1/2 = elimination half-lives;
MRT (hr)	12.5 ± 0.61	6.8 ± 0.95	7.8 ± 0.61	MRT = mean residence time;
Fabs (%)	–	39.4 ± 12.6	90.0 ± 7.20	Fabs = absolute bioavailability.

Figure 8 Concentration versus time profile of CLBQ14 following the administration of 2 mg/kg IV bolus, 10 mg/kg PO and 20 mg/kg SC doses to SD rats (n=3 each, error bar = standard deviation).

Table 5 Tissue-to-Plasma Ratio (K_p) of CLBQ14. Tissue and Plasma Samples Were Collected 2 h After a Single 5 mg/kg IV Bolus of CLBQ14

Organ	Kp (Mean ± SD)
Thymus	0.36 ± 0.04
Pancreas	0.32 ± 0.10
Spleen	0.26 ± 0.09
Kidneys	4.35 ± 0.16
Lungs	0.41 ± 0.09
Heart	0.16 ± 0.03
Liver	1.46 ± 0.34

Figure 9 Tissue distribution of CLBQ14 at 2 hrs following an IV bolus dose of 5 mg/kg to SD rats (error bar = standard deviation).