Development of Microdialysis Probe Method for Partition Coefficient Determination for Pharmacokinetic Modeling.

Partition Coefficient of 133Xe between Blood and Eye Tissues

Nuklearmedizin ◽

10.1055/s-0038-1624911 ◽

1975 ◽

Vol 14 (04) ◽

pp. 301-309

Author(s):

A. Marczak ◽

A. Moszczyńska-Kowalska ◽

H. Kowalski

Keyword(s):

Partition Coefficient ◽

Aqueous Humour ◽

Vitreous Body ◽

Flow Measurements ◽

Solubility Coefficient ◽

Eye Muscles ◽

Eye Tissues ◽

Relative Solubility ◽

Blood Flow Measurements

SummaryThe relative solubility coefficient of 133Xe and the tissue-blood partition coefficient for the aqueous humour vitreous body, conjunctiva and external eye muscles of the rabbit were determined in vitro at 37° C and at various haematocrit values. The partition coefficient for haematocrit 40 was: for the aqueous humour 0,49 ml/ml, for the vitreous body 0,50 ml/ml, for the conjunctiva 0,81 ml/g and for the external eye muscles 0,77 ml/g. It was found that the solubility of 133Xe in rabbit erythrocytes is about 50 per cent higher than that in human red cells. The consequences of this fact for the precision of blood flow measurements by the method of tissue clearance are discussed.

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Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

Nuklearmedizin ◽

10.1055/s-0038-1628899 ◽

1987 ◽

Vol 26 (06) ◽

pp. 253-257

Author(s):

M. Mäntylä ◽

J. Perkkiö ◽

J. Heikkonen

Keyword(s):

Partition Coefficient ◽

Partition Coefficients ◽

Regional Blood Flow ◽

Blood Perfusion ◽

Compartmental Analysis ◽

Malignant Tumour ◽

Mean Value ◽

Perfusion Rate ◽

Biological Variables ◽

The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

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