Selective determination of potential impurities in an active pharmaceutical ingredient using HPLC-SPE-HPLC.

The present paper describes the selective determination of two synthetic intermediates (2,4-dichloro-6,7-dimethoxyquinazoline (IMP-1) and its derivative (IMP-2) as potential impurities in the active pharmaceutical ingredient (API)-A using two-dimensional high-performance liquid chromatography (HPLC) hyphenated via on-line solid-phase extraction (SPE) (HPLC-SPE-HPLC). Two synthetic intermediates that are potential impurities in API-A were concentrated on-line on two Shimadzu MAYI-ODS SPE columns (10 mm×4.6 mm I.

Stereochemistry of pladienolide B.

Pladienolide B is a 12-membered macrolide isolated from Streptomyces platensis Mer-11107. It showed potent in vitro and in vivo antitumor activities and is a potential lead for novel antitumor agents. The absolute configurations at ten chiral centers were determined on the basis of spectral data of pladienolide B and its chemical transformation products.

Synthesis and evaluation of novel pyrimido-acridone, -phenoxadine, and -carbazole as topoisomerase II inhibitors.

As part of a series of studies to discover new topoisomerase II inhibitors, novel pyrimidoacridones, pyrimidophenoxadines, and pyrimidocarbazoles were synthesized, and in vitro and in vivo antitumor activities and DNA-protein and/or DNA-topoisomerase II cross-linking activity as an indicator of topoisomerase II-DNA cleavable complex formation were evaluated. The pyrimidocarbazoles possessed high in vitro and in vivo potencies. Compound 26 (ER-37326), 8-acetyl-2-[2-(dimethylamino)ethyl]-1H-pyrimido[5,6,1-jk]carbazole-1,3(2H)-dione, showed in vitro growth inhibitory activity with respective IC(50) values of 0.

A novel carbazole topoisomerase II poison, ER-37328: potent tumoricidal activity against human solid tumors in vitro and in vivo.

We have discovered a novel topoisomerase II (topo II) poison, ER-37328 (12,13-dihydro-5-[2-(dimethylamino)ethyl]-4H-benzo[c]pyrimido[5,6,1-jk]carbazole-4,6,10(5H,11H)-trione hydrochloride), which shows potent tumor regression activity against Colon 38 cancer inoculated s.c. Here, we describe studies on the cell-killing activity against a panel of human cancer cell lines and the antitumor activity of ER-37328 against human tumor xenografts.

Antitumor activity of ER-37328, a novel carbazole topoisomerase II inhibitor.

DNA topoisomerase II has been shown to be an important therapeutic target in cancer chemotherapy. Here, we describe studies on the antitumor activity of a novel topoisomerase II inhibitor, ER-37328 [12,13-dihydro-5-[2-(dimethylamino)ethyl]-4H-benzo[c]pyrimido[5,6,1- jk]carbazole-4,6,10(5H,11H)-trione hydrochloride]. ER-37328 inhibited topoisomerase II activity at 10 times lower concentration than etoposide in relaxation assay and induced double-strand DNA cleavage within 1 h in murine leukemia P388 cells, in a bell-shaped manner with respect to drug concentration.