PRT is fairly generic format for "parts", or 3D models of some mechanical parts created using a CAD software. So it is likely at least some of the PRT formats can be used and exported or converted to IPT format from Autodesk Inventor.
Convert CAD 3D part or component to AutoDesk Inventor CAD part.
We found one software available in the database for this conversion.
Microsoft Windows software - convert prt to ipt on Windows
A 2D and 3D CAD construction software
Convert from prt file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.