What the Heck Is methylene blue usp grade?

https://medium.com/@o7eeoqp791/what-sports-can-teach-us-about-methylene-blue-usp-grade-d2f1746dcbf

Hydrosalpinx is one of the common diseases of chronic tubal inflammation, which is due to the obstruction of the end of fallopian tube. This kind of obstruction was caused by the inflammation accompanied by pathogen