The volume distribution is the theoretical volume into which (for example a drug) is distributed into the body.

The apparent volume is the volume into which the drug is KNOWN to distribute in the body.

yes

It accounts for apporx 0.934% (by volume) of the earth's atmosphere.

"all-commodity volume weighted distribution" It is a commonly accepted measure of product distribution. It is the basis for most retail distribution measures by AC Nielsen & IRI.

in pharmacokinetics, we can use volume distribution (Vd) of a drug to calculate the dose that needs to be prescribed.

volume distribution is the theoretical volume the drug will have to occupy (if it were uniformly distributed), to provide a concentration as it currently is in blood plasma.

Vd = (amount of drug in blood) / (drug plasma concentration)

children are physically smaller than adults, hence they will have a smaller volume distribution and hence only need to be prescribed a smaller dosage of the drug.

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