A 96-well plate assay for CYP4503A induction using cryopreserved human hepatocytes.

A reliable and practical CYP3A induction assay with cryopreserved human hepatocytes in a 96-well format was developed. Various 96-well plates with different basement membrane were evaluated using prototypical inducers, rifampicin, phenytoin, and carbamazepine. Thin-layer (TL) Matrigel was found to yield the highest basal and induced levels of CYP3A activity as determined by testosterone 6β-hydroxylation.

Preconcentration technique for nonylphenol using cellulose cotton with homogenous liquid-liquid extraction for liquid chromatographic analysis.

A powerful preconcentration method for nonylphenol (NP) has been developed for liquid-chromatography by combining the use of cellulose cotton (solid-phase extraction) with homogeneous liquid-liquid extraction. A 100 ml of sample solution was preconcentrated using cotton, and the eluate obtained (acetonitrile; 5 ml) was further preconcentrated to 50 microl within 10 min using a homogeneous liquid-liquid extraction method (volume ratio, 2,000-fold; 100 ml--> 50 microl). The sample concentration increases from preconcentration was 1,599-fold, and NP was extracted into the sedimented phase at 80%.