Hello,

I think in a way you have answered your own question. Peptides are really susceptible to enzymatic degradation, along with degradation as a result of pH changes and mechanical damage. The biodegradable nature of the peptide is a result of the enzymatic susceptibility, so to design a peptide hydrogel for drug delivery you need to carefully consider a) what you wish to deliver b) where the target site is and c) how long should the drug be delivered over. 

If you want the drug to be delivered quickly, then it doesn't really matter how proteolytically stable it is, because you want it to be delivered fast (although I doubt this is the case). If you want the hydrogel to be stable over a long amount of time and for the release to be controlled, then it is important that the gel isn't susceptible to enzymatic degradation. By designing your peptide properly, you can minimise this, as enzymes will only cleave specific domains. That being said, unless you intend to chemically crosslink your peptide hydrogel, it is likely that the rate of biodegradability will naturally be quick.

I hope this helps somewhat, good luck!

Laura

Thanks Laura for your valuable answer.  

Hi,

Laura has already answed it well. To add more, If you donot want burst release of the drug from peptide hydrogel then you should take care of proteolytic stability. Moreover, hydrogel should be biodegradable at the rate you want. So, we should consider both while designing the experiment.

Thanks Kamal for your answer. But, designing of ideal peptide hydrogel for drug release with good proteolytic stability is difficult.  Like,  you designed a hydogel showing proteolytic stablility up to 48 hours ( in vitro study by enzyme) and after that it slowly degraded. So, it becomes both proteolytic stable and biodegradable. But, when you applied it in vivo it may differ because of complex system. That's the real problem.