Aggregate Formation of p-Hydroxybenzoic Acid Esters in Aqueous Solution.

Fukahori, Masahiro; Takatsuji, Yasuo; Yamakita, Takahiro; Takahashi, Hiroaki; Sato, Hiroshi; Yotsuyanagi, Toshihisa

doi:10.1248/cpb.44.245

Cited by 5 publications

(1 citation statement)

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“…Where Rϑ is the Rayleigh ratio, A is the calibration constant of the apparatus, n and n b are the refractive indices of water and toluene used for calibration, and I and I 0 are the intensities of scattered and introduced laser light, respectively. The apparent molecular weight of FK906 aggregates, mw, was determined according to eq 2: 9 Where K is the optical constant, R 0 is the Rayleigh ratio at critical micelle concentration, C 0 is the second virial coefficient, and P(ϑ) can be assumed to be 1 when the particle size is small enough.…”

Section: Light Scattering Studies On Micelle Formationsmentioning

confidence: 99%

Interaction between Surface Active Drug (FK906:Rennin Inhibitor) and Cyclodextrins in Aqueous Solution

Kitamura¹,

Fujimura²,

Kohda³

1999

Journal of Pharmaceutical Sciences

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The aggregation behavior of FK906, which is a peptide like hypertensive agent, in aqueous solution was studied by static light scattering, 1H-nuclear magnetic resonance (NMR), and surface tension. These experiments showed a clear critical micelle concentration (cmc) at around 6.3 x 10(-3) to 1.3 x 10(-2) M of FK906 aqueous solution. The result of 1H NMR experiments revealed that FK906 aggregates primarily by hydrophobic interactions involving the benzyl moiety. The Debye plots from light-scattering studies showed that the apparent molecular weight of aggregated FK906 molecule is 1670 which corresponds to 2-3 molecules of FK906. The effect of alpha- and beta-cyclodextrins on the surface tension of FK906 aqueous solution was investigated. It appeared that the addition of alpha-cyclodextrin showed very small shift of cmc, but that of beta-cyclodextrin shifted the cmc to much higher concentration. The investigation on the surface tension of FK906 aqueous solution in the presence of beta-cyclodextrin indicated that FK906 forms a 1:1 complex with beta-cyclodextrin. On the basis of these experiments, it appears that beta-cyclodextrin has an ability to change the surface active property of FK906 in its aqueous solution. Therefore, it is expected that the addition of beta-cyclodextrin to FK906 aqueous solution may prevent the adsorption onto container walls and/or reduce the local irritancy.

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Section: Light Scattering Studies On Micelle Formationsmentioning

confidence: 99%