Is there a copy of the Gīta that has no purport interruptions?
Try this translation of Bhagavad-gītā by Gorakhpur Gita Press on Google Drive:
You cannot download or print it but you can read it for free at that link.
Here's a sample from the free e-book.
Why have detailed explanations between each verse?
Isn't the objective of any sacred text that you pick up to read or any other book for that matter to grasp complete and total knowledge from it? In the case of Gīta, what if you do not understand a verse (example: see this, this and this)? Would you google for an in-depth explanation of the verse or rather have it all explained in the same book you were originally reading? The purport or commentary on the verses you find in books are meant for more advanced readers of the Gīta.
For more explanations, see answers under How to start reading the Bhagavad-gītā?
You can find other free e-books from Gorakhpur Gita Press in English and other languages at the link below.
DISCLAIMER: I'm not related to Gorakhpur Gita Press in anyway nor is this answer an advertisement.