For formulation of novel drug delivery system using plant extract some essential test is required

First try learn about solubility.

Presence of active metabolites in your extracts

Qualitative and quantitative estimation of your active metabolites in extract as well as in formulation.

for formulation of drug delivery system by using active plant extract you should know about their cytotoxicity as well as some other necessary test. 

Dear Neeraj, thank you for your answer.

I think that you said is chromatography. Is not it?

Thanks Fahad!

Dear Paula

Yes, chromatography is best method for separation and identification of plant metabolites.

First of all Perform chemical identification tests for different types of phytoconstituents.

separate them  by column chromatography, Check which fractions toxicity and Biological activity.

Thank you so much Rakesh!