Hi Saidhbhe, the most important questions of pharmacokinetics of small drugs are:

1) does the drug bind to serum albumin?,

2) how well does the drug bind to serum albumin?

3) how can we improve the drug binding to serum albumin? 

If a drug does not bind serum albumin, it will be filtered out by the kidneys in minutes and end up in the toilet.

So the simplest benchtop way to see if a drug is a viable candidate is its binding to serum albumin.  It doesn't matter what organ you are looking at. Kidneys effectively filter out anything under 40 kDa. Albumin is ~68 kDa. Stuff bound to albumin stays around. Anything smaller will be filtered and flushed. 

Thank you, nicely put and I have decided on equilibrium dialysis the following gives a good guide DOI: 10.1038/mp.2015.229 

Hello,

Was about to suggest:

1. Benchtop way: BSA-Drug "spectrophotometry" to do a kinetics study at 280 nm for BSA and if any or 220 nm absorption for "drug". Can be done in visible range as well.

2. Spectrofluorimetry: Binding kinetics etc.

3. MALDI-ToF to determine the ration/ stoichiometry of binding worked well for me- and if a MALDI is around, it is bench top as sample preparation and data analysis is like non-existent. : )

Thanks,