Measurement of Diffusion Coefficients of Parabens and Steroids in Water and 1-Octanol

Abstract

Diffusion coefficients (D) of parabens and steroids in water and 1-octanol were determined by using the chromatographic broadening method at 37 degrees C, and the relationships between the D values and the physicochemical properties of the drugs were discussed. The D values in 1-octanol were lower than those in water because of the higher viscosity of 1-octanol. The D values depend on not only the molecular weight (MW), but also the lipophilicity of the drugs in water and on the ability for hydrogen-bonding in 1-octanol. When the lipophilic index (LI), calculated from the retention time using in a reverse-phase column, was used as a parameter of drug lipophilicity, the following equation was obtained for D in water (D(w)); log D(w)=-0.215.log MW-0.077.log LI-4.367. When the hydrogen bond index (HI), the logarithm of the ratio of the partition coefficient of the drugs in 1-octanol and cyclohexane, was used as an index of hydrogen-bonding, the following equation was obtained for D in 1-octanol (D(o)); log D(o)=-0.690.log MW-0.074.log HI-4.085.

Leakiness and Size Exclusion of Paracellular Channels in Cultured Epithelial Cell Monolayers–Interlaboratory Comparison

“…The aqueous diffusivity data at 25°C were collected from standard tabulations (25,27,28), Flynn et al (23), and sources containing measured data for drug molecules (29,30). The 160 compounds with MW<1,200 Da (cf., Supplemental Table) were analyzed using linear regression, as had been done by us earlier for 87 molecules (21).…”

Culture of Calu-3 Cells at the Air Interface Provides a Representative Model of the Airway Epithelial Barrier

“…First, diffusion coefficients (D) for each solute were calculated according to the method of Seki and coworkers (25), which has been applied to the diffusion of dextrans (26). log D ¼ À0:434 log MW À 0:4059 ð3Þ…”

Diffusion coefficients in ethanol and in water at 298K: Linear free energy relationships

“…The models were based on experimental Abraham descriptors [46] alone and in combination with other molecular properties. It was expected that an approach involving Abraham descriptors would give a reasonable prediction of diffusion because the Abraham equation includes terms for describing molecular volume (V) and hydrogen bond acid and base properties (A and B), which have previously been included in literature models of diffusion [38,39,[47][48][49]. Tables 1 and 2 show the collected diffusion data in water and ethanol, respectively.…”