Stan's guide has this to day about that: Some people have discussed or used putting SN into capsules. This only removes the point of the salty taste in your mouth. People have still been sick after taking capsules as the human body will still react to poisoning regardless of if it is in water or capsules. There is also the potential for the SN to be slowly released into your system which could extend the time to death significantly.
I just used the search function in the google docs about successes and failures and it seems people have died doing it with capsules. Might be helpful for you to view these cases yourself here: LINK