Granin's patent protection period ends on April 20 13. Patents are divided into inventions, utility models and designs. The protection period of inventions is 20 years, and that of utility models and designs is 10 year. From the date of application. 1, invention patent-20 years; 2, the utility model-10; 3. Design-10 year. The drug patent is valid for 20 years. According to relevant regulations, the term of invention patent is 20 years, and the term of utility model patent and design patent is 10 years, all of which are counted from the date of application. Because drugs are inventions, the patent term of drugs is 20 years. Legal basis: People's Republic of China (PRC) Patent Law.