Pharmacokinetics is the study of how drugs are absorbed, distributed, metabolized and eliminated by the body. It is a key component of drug development, as it determines the timing, rate and level of drug exposure in the body. Pharmacokinetics is also invaluable in the drug’s safety, effectiveness and dosage regimen optimization. Pharmacokinetics helps pharmaceutical companies to design drugs which are safer, more effective, and more appropriate for the patient's individual needs. It also helps physicians choose the most appropriate and effective drug for each patient.