Fraction Drug Dissolved (FRD) and Fraction Drug Absorbed (FRA)

Greetings,

I would like to ask what is the difference between Fraction Drug Dissolved and Fraction Drug Absorbed? Then how to calculate these 2 parameters.

Thank you.

FDiss is from an in vitro experiment where you measure the form dissolving.

FAbs is assessed in vivo as to what fraction of drug is absorbed, you may think of it as Bioavailabilty being calculated over time.

So I just need to see how many mg are dissolved in a given time in order to calculate FDiss?

normally you use defined apparatus and media to replicate GI tract as defined in United States Pharmacopeia (USP) e.g. Apparatus 1 (baskets), 2 (paddles), 3 (reciprocating cylinder), 5 (paddle over disk), 6 (rotating cylinder), and 7 (reciprocating disk).

Okay thank you for your explanation.