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Hi, all
For measuring the drug concentrations in different tissues like lung,
liver etc.. etc.. what weight of the tissue (Wet or dry ??) should be
taken into account for making a homogenate.
If it's homogenised in 4 volumes of buffer (w/v) than how best to get
the concentrations in mcg/g of the tissue.
Nikhil
[Weigh the empty vial, with tissue (wet - blotted maybe), with buffer,
homogenize, take weighed sample for assay should give you enough
information. Blood content is a different story - db]
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The following message was posted to: PharmPK
Hi Nikhil,
Weight of the tissue that is to be taken always depends on the
concentrations you are expecting in the tissue. Depending on the
pharmacological class to which the compound belongs, one might be
having a rough idea of the probable target organs. Basing on that you
can decide upon the weight of the tissue that has to be taken and the
dilution that is to be carried out with the buffer. If you are not
having any idea, the pragmatic assumption that can be made is that
highly perfused organs such as lungs, liver etc. will be having higher
concentrations.
Regarding the calculation:
Its always better to carry out the calibration curve taking absolute
amounts instead of going by concentration. After homoginization you
will be taking an aliquot and going for the analyisis. From the
calibration curve, you will be directly getting the amount present in
the aliqout. As you know the initial weight of the tissue you have
taken for homoginization you can get the amount present in that
portion. From that you can extrapolate it to the total amount present
in the organ which can be expressed in concentration unites/ gram of
tissue.
Hope this is helpful to you.
In case you require any further information feel free to mail me.
Ravi
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