Dicloxacillin [BSA]

Drug-induced liver injury (DILI) is a major problem in drug development and clinical drug therapy. In most cases, the mechanisms are still unknown. It is difficult to predict DILL in humans due to the lack of experimental animal models. Dicloxacillin, penicillinase-sensitive penicillin, rarely causes cholestatic or mixed liver injury, and there is some evidence for immunoallergic idiosyncratic reaction in human. In this study, we investigated the mechanisms of dicloxacillin-induced liver injury. Plasma ALT and total-bilirubin (T-Bil) levels were significantly increased in dicloxacillin-administered (600 mg/kg, i.p.) mice. Dicloxacillin administration induced Th2 (helper T cells)-mediated factors and increased the plasma interleukin (IL)-4 level. Neutralization of IL-4 suppressed the hepatotoxicity of dicloxacillin, and recombinant mouse IL-4 administration (0.5 or 2.0 mu g/mouse, i.p.) exacerbated it. Chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTh2) is a cognate receptor for prostaglandin (PG) D. and is suggested to be involved in Th2-dependent allergic inflammation. We investigated the effect of 13,14-Dihydro-15-keto-PGD(2) (DK-PGD(2); 10 mu g/mouse, i.p.) administration on dicloxacillin-induced liver injury. DK-PGD(2)/dicloxacillin coadministration resulted in a significant increase of alanine aminotransferases and a remarkable increase of macrophage inflammatory protein 2 expression. In conclusion, to the best of our knowledge, this is the first report to demonstrate that dicloxacillin-induced liver injury is mediated by a Th2-type immune reaction and exacerbated by DK-PGD(2). (C) 2010 Elsevier Ireland Ltd. All rights reserved.

A multiresidue analytical method was developed for the quantification of benzylpenicillin (PCG), phenoxymethylpenicillin (PCV), oxacillin (MPIPC), cloxacillin (MCIPC), nafcillin (NFPC) and dicloxacillin (MDIPC) in bovine tissues using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) with a multiple reaction monitoring technique. Using the deuterated PCG and NFPC as internal standard was effective for improvement of repeatability and accuracy. We chose [M-H-141](-) as a monitor ion of MRM analysis and [M-H](-) as a precursor ion for each penicillin. Combination of an ion-exchange cartridge clean-up and ion-pair LC enable us to determine the residual penicillins using the standard curves made from standard solutions without the influence of sample matrix on the MS. The average recoveries of PCG, PCV, MPIPC, MCIPC, NFPC and MDIPC from bovine liver, kidney and muscle at the same concentrations as the tolerance levels of PCG (50 mug/kg) ranged from 77 to 101% with the coefficients of variation ranging from 0.7 to 4.2% (n=5). The limits of quantification for the six penicillins were 2-10 mug/kg in bovine muscle, liver and kidney (S/N ratio>10). (C) 2004 Elsevier B.V. All rights reserved.