Intestinal absorption and biliary elimination of glycyrrhizic acid diethyl ester in rats

Figures & data

Figure 1 Structure of GZ (A) and GZ-DE (B).

Abbreviations: GZ, glycyrrhizic acid; GZ-DE, glycyrrhizic acid diethyl ester.

Table 1 Pharmacokinetic parameters for GZ-DE and GZ after intravenous administration of GZ-DE (GZ dose 2 mg per rat)

Parameter	GZ-DE	GZ
A (μg/mL)	28,964 ± 1342	3,470 ± 425
α (per hour)	4.56 ± 0.36	3.35 ± 0.33
B (μg/mL)	37.5 ± 2.6	36.0 ± 2.7
β (per hour)	0.245 ± 0.042	0.148 ± 0.022
t 1/2β (hours)	2.63 ± 0.23	4.68 ± 0.46
AUC (μg ⋅ h/mL)	6,502 ± 428	1,278 ± 142
CLtotal (mL/hour)	0.26 ± 0.03	1.56 ± 0.21

Note: The data represent the mean ± standard deviation of three experiments.

Abbreviations: GZ, glycyrrhizic acid; GZ-DE, glycyrrhizic acid diethyl ester; AUC, area under the concentration-time curve; CLtotal, total clearance; A, ordinate intercept in initial phase; α, first-order elimination rate constant in initial phase; B, ordinate intercept in second phase; β, first-order elimination rate constant in second phase.

Figure 2 Bile GZ-DE (A) and GZ (B) concentration versus time profiles after intravenous administration of GZ-DE (GZ dose 2 mg per rat). The data represent the mean of three experiments. Standard deviation bars are shown with each symbol.

Abbreviations: GZ, glycyrrhizic acid; GZ-DE, glycyrrhizic acid diethyl ester.

Figure 3 GZ-DE and GZ eliminated in bile after intraduodenal (A), intraileal (B), and oral (C) administration of GZ-DE (GZ dose 5 mg per rat). The data represent the mean ± standard deviation of four experiments.

Abbreviations: GZ, glycyrrhizic acid; GZ-DE, glycyrrhizic acid diethyl ester.

Figure 4 Stability of GZ-DE in distilled water, pH 1.2 solution, 0.9% NaCl solution, and 50 mM phosphate-buffered solution (pH 7.4). The initial GZ concentration in each test solution at the start was set to 200 μg/mL (A and B) and 3 μg/mL (C and D). The incubation temperature was set to 37°C. The data represent the mean ± standard deviation of three experiments.

Abbreviations: GZ, glycyrrhizic acid; GZ-DE, glycyrrhizic acid diethyl ester.