If it is necessary for your work, it is not backbiting. Writing for publication is a public activity, and anything written and presented publicly can be discussed in an honest and sincere way.
It is better to say that it is poor quality in the beginning than to publish poor quality material and be an embarrassment to Islam and Muslims.
However it is good to be tactful and choose nice ways to phrase your criticisms since writing is a very sensitive subject. Perhaps some tips on how it could be improved might also be useful.