What happens when you export PDF using File > Export > Adobe PDF (Print) instead of using PostScript. Using PostScript and Acrobat Distiller is an archaic workflow which loses much information, and is not the recommended method of creating a PDF file.
Thank you for your response.
We have created these equations in mathtype and then copy and paste them in PM. Now when we are opening these files in indesign then the equations are missing or appearing as images. We want the equations appeared in mathtype itself so if we have any corrections we can change them direstly in mathtype instead of using illustartor.
Can it be possible.