"This is a good process to improve because one year ago nobody was asking about our players," he said.
"Now there are big, big teams and my players must be very proud of this but maintain their way.
"He signed a new contract and he doesn't have a clause and if Manchester want him it is okay. We don't want to sell anybody.
"We only lost (N'Golo) Kante because he had a clause but no other player we lost. We want to keep all the players and all the squad."
Drinkwater has played in every game of Leicester's season so far, including 120 minutes of Tuesday's 4-2 extra time EFL Cup defeat to Chelsea.
Under Ranieri he has won three England caps and the Premier League title and Drinkwater credits the Italian with restoring his self-belief.
"Before he joined the club I had a season where I didn't really play a lot of football," he said.
"He is picking me week in week out so I obviously thank him for that. He has put a lot of trust in me and I am hopefully repaying him. I am sure you can tell at the outside just what we have achieved since he has been here."