Crizotinib is used in the treatment of some kind of non-small cell lung cancer (NSCLC) that spreads to nearby tissues or to other parts of the body27.Crizotinib helps to stop the growth of tumor cells by blocking the anaplastic lymphoma kinase (ALK) protein from working; it is also termed as fusion mutation. Appropriate dosage is attained with proper drug particle size and it is very critical for the treatment of cancer. The gene discussed is ALK; the disease is cancer.