Synthesis and Hepatic Transport of Strongly Fluorescent Cholephilic Dipyrrinones

Abstract

A new class of highly fluorescent (phi(F) 0.3-0.8) low molecular weight water-soluble cholephilic compounds has been synthesized in two steps from dipyrrinones. The dipyrrinone nitrogens are first bridged by reaction with 1,1'-carbonyldiimidazole to form an N,N'-carbonyldipyrrinone (3H,5H-dipyrrolo[1,2-c:2',1'-f]pyrimidine-3,5-dione) nucleus, and a sulfonic acid group is then introduced at C(8) by reaction with concd H(2)SO(4). The resulting sulfonated N,N'-carbonyl-bridged dipyrrinones ("sulfoglows") are isolated as their sodium salts. When the alkyl substituents of the lactam ring are lengthened from ethyl to decyl, sulfoglows become increasingly lipophilic while maintaining water solubility. Low molecular weight sulfoglows were rapidly excreted intact in both bile and urine after intravenous infusion into rats, but higher molecular weight sulfoglows were excreted more selectively in bile. Hepatobiliary excretion of sulfoglows was partially, but not completely, blocked in mutant rats deficient in the multidrug-resistance associated transport protein Mrp2 (ABCC2). These observations point to the feasibility of developing simple sulfoglows with clinical diagnostic potential that are normally excreted in bile but appear in urine when hepatic elimination is impaired by cholestatic liver disease.

Crystallographic Analysis of Human Serum Albumin Complexed with 4Z,15E-Bilirubin-IXα

“…Bilirubin (Sigma-Aldrich) containing 6% 4 Z ,15 Z -bilirubin IIIα, 87% 4 Z ,15 Z -bilirubin IXα and 5% 4 Z ,15 Z -bilirubin XIIIα and <2% Z , E isomers (as determined by HPLC) 51 was dissolved immediately before use at 10 mM in dimethylsulfoxide (DMSO) in a foil-wrapped microcentrifuge tube. The bilirubin and HSA solutions were mixed to give a bilirubin to HSA molar ratio of 1.1:1 and 3:1, and incubated with rotation in the dark overnight at room temperature.…”

Pyrrole: a resourceful small molecule in key medicinal hetero-aromatics

“…They are thus useful in clinical diagnosis as they will appear in urine when hepatic elimination is impaired by cholestatic liver disease. 33…”

Automated Applications of Sandwich-Cultured Hepatocytes in the Evaluation of Hepatic Drug Transport

“…4 ) that is taken up by unknown hepatic transport proteins and is excreted into bile by Mrp2 and an Mrp2-independent pathway. 16 The hepatobiliary disposition of this substrate was evaluated in automated SCRH studies, and results consistently showed significant accumulation (cells + bile = 180 ± 27 pmoles/mg protein; cells= 110 ± 9.2 pmoles/mg protein) and a relatively high BEI (41 ± 8.6) in SCRH ( n = 6 ), which are both desirable probe quantities.…”

“…[13][14][15] Sulfoglow 1a was selected as a novel substrate to evaluate with automated studies because it is a water-soluble, fluorescent molecule with some structural similarities to bilirubin, and it is rapidly taken up and excreted intact following intravenous injection into rats. 16 Bilirubin and its glucuronide conjugates are well-recognized markers of hepatic dysfunction. 17 Here, we demonstrate the use of the applications described above using SCRH in a fully automated format.…”