Comparative metabolic study between two selective estrogen receptor modulators, toremifene and tamoxifen, in human liver microsomes.

Toremifene (TOR) and Tamoxifen (TAM) are widely used as endocrine therapy for estrogen receptor positive breast cancer. Poor metabolizers of TAM are likely to have worse clinical outcomes than patients who exhibit normal TAM metabolism due to lower plasma level of its active metabolite, 4-hydroxy-N-desmethyl (4OH-NDM) tamoxifen (endoxifen). In this study, we examined the role of individual cytochrome P450 (CYP) isoforms in the metabolism of TOR to N-desmethyl (NDM), 4-hydroxy (4OH) and 4OH-NDM metabolites in comparison with TAM using human liver microsomes (HLMs) with selective chemical inhibitors for each CYP isoform and recombinant CYP proteins.

Preclinical anticancer effects and toxicologic assessment of hepatic artery infusion of fine-powder cisplatin with lipiodol in vivo.

We conducted an in vivo study to evaluate the anticancer effect and toxicity of fine-powder cisplatin suspended in lipiodol (fCDDP/LPD suspension) after a single administration of three different doses to rats via the intrahepatic artery after transplantation of rat ascites hepatoma cells. The toxicity of the fCDDP/LPD suspension was also assessed in the same protocol in noncancer-bearing rats and the observed toxicologic changes were compared among groups administered saline (Sal), an aqueous solution of fCDDP (fCDDP/Sal solution), and LPD alone. In parallel with the toxicity test, plasma CDDP concentrations were compared between the fCDDP/LPD suspension and fCDDP/Sal solution.

Sensitive measurement of vinorelbine in dog plasma by liquid chromatography-electrospray ionization tandem mass spectrometry utilizing transitions from double-charged precursor ions.

A sensitive high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for measuring vinorelbine was developed. A 100 µL aliquot of plasma was spiked with deuterium-labeled internal standard and subjected to solid-phase extraction using an Oasis HLB μ-elution plate. Two microliters of the extracted samples was directly injected into LC/MS/MS.

[Applicability of atmospheric pressure photoionization mass spectrometry to trace analysis of hydrophilic drugs].

Applicability of atmospheric pressure photoionization mass spectrometry (APPI-MS) to the analysis of hydrophilic drugs was investigated. Model compounds with moderate to high hydrophilicity was tested, and most compounds showed good signal response with APPI-MS, but some compounds with high molecular polarity like folic acid derivatives, glycoside and some nucleic acid derivatives showed very weak signal responses. By observing relationship between the compounds' physicochemical properties and APPI response, compounds with higher lipophilicity and less polar surface area were considered to be advantageous for APPI-MS.

Effects of long-term low-dose oxygen supplementation on the epithelial function, collagen metabolism and interstitial fibrogenesis in the guinea pig lung.

Background: The patient population receiving long-term oxygen therapy has increased with the rising morbidity of COPD. Although high-dose oxygen induces pulmonary edema and interstitial fibrosis, potential lung injury caused by long-term exposure to low-dose oxygen has not been fully analyzed. This study was designed to clarify the effects of long-term low-dose oxygen inhalation on pulmonary epithelial function, edema formation, collagen metabolism, and alveolar fibrosis.