First, I have been told that purse carry in general is not recommended because the first thing the criminal is going to go for is her purse. So if he has her purse he then also has her means of self defense.
Assuming you are going to ignore the above warning the second thing people have told me was that a revolver inside the purse makes sense because you don't have to worry about the slide needing space to cycle or going out of battery. You can fire a revolver directly from inside the purse if necessary.
Assuming you don't want a revolver I would recommend the Kahr PM9 which is 9mm and not .380. For self defense 9mm is better.
Assuming you really like .380's I can recommend the Kahr P380 which I have one and let my daughter train with. I also have heard great things about the Sig P238 which to me looks like a mini 1911 although it is heavier.
If she does purse-carry make sure she uses a holster (pocket or otherwise) so that her lipstick doesn't cause a ND :-0
If you decide to go with a revolver try to get a hammerless one so that the hammer doesn't get caught up on anything in the purse.
There are alot of great guns out there so have fun (no sarcasm intended) searching for the right one. And remember you don't only have to get one. :-)