Correlation analysis between food effects on oral drug absorption (food effect) and physicochemical properties is important for efficient drug discovery and contributes to drug design. This study focused on micelle binding and solubilization considering bile micelles in the intestinal fluid. Profiling using about 40 launched drugs demonstrated that those in a high solubilization area (area 1) tended to have a positive food effect, and that drugs exhibiting negative/no food effect tended to coexist in a no/low solubilization area (area 2). In area 1, the solubilization effect by bile micelles was demonstrated quantitatively as an important factor that indicates a positive food effect. In area 2, the relative and quantitative relationships among the membrane permeation rate, dissolution rate, micelle binding and food effect could be clarified by simulation. The improvement of membrane permeability and the suppression of micelle binding are considered to be required to avoid a negative food effect. In conclusion, important factors contributing to the food effect were clarified relatively and quantitatively. Data generated from this profiling may be beneficial to find a solution for negative food effects. Furthermore, this risk assessment of food effects is considered to be a useful tool in rational drug design for drug discovery.

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A convenient assay specific to lipid hydroperoxide in plasma is presented. Cytochrome c heme peptide obtained from Saccharomyces was found to emit a strong chemiluminescence with any hydroperoxide, but not with TBA‐reactive substances. The benefit of measuring this luminescence using photon counting is discussed with respect to in vivo lipid peroxidation.

Water (10−3 mg H2O in 1 mg of biopolymer) was extracted from biological compounds with acetonitrile and determined by FT-IR spectrometry with the use of a KBr transmission cell. A nitrogen-gas-purged glove box was employed during the extraction to avoid errors due to water absorption from ambient laboratory air. The subtractive compensation for concomitant water in acetonitrile was further accomplished by using a reference spectrum of acetonitrile kept under the same experimental conditions as those for preparing the acetonitrile extracts of water from the testing samples. This technique was applied to the quantification of water in peptides and enzymes. The advantages of this technique over the Karl Fisher titration are discussed, along with measurements for loss of weight on drying in vacuo.

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