How many years is the patent protection of drugs?

A drug patent can only be an invention patent. According to the laws of China, the protection period of an invention patent is 20 years. A drug patent is a patent declared for the formula or preparation process of a drug. Patented drugs do not necessarily conform to the concept of new drugs, because the same drug can apply for different patents because of different preparation methods. In Article 42 of the Patent Law of People's Republic of China (PRC), the term of the invention patent right is 20 years, and the term of the utility model patent right and the design patent right is 10 years, all of which are counted from the date of application.