Give this a shot.

(<[^>]*>)[^<>/]*(padding)[^<>/]*(</[^>]*>)

Same trick as before the middle group is what you want to replace each time. First and Third groups are the html tags around content. Any word you want to find can be put into that middle group.

(<[^>]*>)[^<>/]*(something)[^<>/]*(</[^>]*>) 

I hope that helps,

Brendan