App to edit IPTC fields in RAW & JPG images?

[NACarter]

I'm after an application which will allow me to edit the IPTC fields in images. These images will have been imported onto my Nexus 7 using the Nexus Media Importer, and will be either in JPG or RAW format. I'm particularly interested in being able to fill in the caption and keyword fields on my Nexus when I'm away from home so that I can then import the images into Lightroom on my PC when I'm back home.

I had an application to do this when I had an iPad, but I haven't been able to find anything suitable for Android.

Thanks.

Nick