COLLANDER

An overview of permeability assays is presented in Table 2.2. As discussed earlier in this chapter, these permeability scales are correlated to each other as well as the various hpophilicity scales via extended Collander equations. 

Further reduction is possible. To a good approximation, partition coefficients from different organic solvents may be interrelated by the so-called Collander equation [364,587] logKp3 = a log Kp2 + c, or Kp3 = 10CK 2, where a and c are constants. Equations (7.38)-(7.40) can be expressed in log forms as a function of just one partition coefficient (i.e., Kp = Kpl) ... 

Collander Relationship between 2% DOPC and 20% Soy Intrinsic Permeabilities... 

The 20% soy lecithin (Table 7.17) and the 2% DOPC (Table 7.15) intrinsic permeabilities may be compared in a Collander equation, as shown in Fig. 7.44. The slope of the regression line, soy versus DOPC, is greater than unity. This indicates that the soy membrane is more lipophilic than the DOPC membrane. Intrinsic permeabilities are generally higher in the soy system. Three molecules were significant outliers in the regression metoprolol, quinine, and piroxicam. Metoprolol and quinine are less permeable in the DOPC system than expected, based on their apparent relative lipophilicities and in vivo absorptions [593]. In contrast, piroxicam is more permeable in DOPC than expected based on its relative lipophilicity. With these outliers removed from the regression calculation, the statistics were impressive at r2 0.97. 

Figure 7.44 Collander relationship between intrinsic permeabilities of 20% soy lecithin versus 2% DOPC PAMPA models.

Collander, R., The partition of organic compounds between higher alcohols and water, Acta Chem. Scand. 5, 774-780 (1951). 

Colland, F., Fujita, N., Ishihama, A., and Kolb, A. (2002) The interaction between sigmaS, the stationary phase sigma factor, and the core enzyme of Escherichia coli RNA polymerase. Genes Cells 7, 233-247. 

Collander, R. (1954). The permeability of Nitella cells to non-electrolytes, Physiol. Plant., 7, 420-445. 

It is known that the RPLC retention parameters are often strongly correlated to the analyte s distribution coefficient in organic solvent/ water. Generally, the relationship between liquid/liquid (LL) distribution and RPLC retention are of the form of the dimensionless Collander-type equations, e.g., see Eq. (15.21)... 

Roberts et al. criticized the attempts to predict permeabilities since permeability is the result of two processes, partitioning and diffusion [40], Therefore, instead of following the approach of Potts and Guy, Roberts et al. tried to find a predictive model for each of these processes separately. For the partitioning step they found a Collander-type linear relationship (Eq. 11) between the logarithms of the stratum corneum-water and the octanol-water partition coefficients with a high correlation coefficient (r2 = 0.839) ... 

Combining the equation for the diffusion coefficient with a Collander-type expression for the lipid-water partition coefficient resulted in an expression for calculating the permeability across the stratum corneum ... 

Collander R (1947) On lipid solubility . Acta Physiol Scand 13 363-381. 

Collander R (1950) The distribution of organic compounds between isobutanol and water. Acta Chem Scand 4 1085-1098. 

Collander, R. The partition of organic compounds between higher alcohols and water, Acta Chem. Scand., 5 774-780,1951. Collett, A.R. and Johnston, J. Solubility relations of isomeric organic compounds. VI. Solubility of the nitroanilines in various liquids, J. Phys. Chem., 30(l) 70-82, 1926. 

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