I don't really get the point of your question. What do you mean with "maximum release"?
First, you must think about the method to determine the release. There are several options: UV-vis absorption, HPLC-MS, MS, NMR, IR ... depending on your drug.
Then you draw a graph "accumulative release" over time. Ideally, the asymptotic curve gets into a 100% release within a reasonable time (within your experiment).
Alternatively, you can draw a graph "measured release" over time. Then you might get a maximum, but this graph will not tell you a lot, since this "maximum release" depends on the sampling intervals.
I use a UV-vis spectroscope to calculate the release % at time (t) which is equal to the absorbance of the drug at time (t)/max. absorbance of encapsulated cargo. I’m working on calcein loaded in Fe-based MOF.