Pharmaceuticals - Fundamentals of Industrial Chemistry: Pharmaceuticals, Polymers, and Business - page 163

CHAPTER 10
Pharmaceuticals
10.1 THE DRUG DEVELOPMENT PROCESS
It is a long process to bring a drug to market. Early experimentation leads to
a compound that has potential to enter into clinical trials. This is often called
the discovery phase and generally takes three to five years [1]. During discov-
ery, leads are identified and optimized. Assays are developed and validation
work is done. Often many structurally similar compounds are synthesized
and studied. Next, preclinical studies are done to test the safety in animals,
stability testing is done, and the drug metabolism is studied. The preclini-
cal phase typically takes about one to two years. At this point, if everything
looks promising, an Investigational New Drug application (IND) is filed with
the FDA. The IND includes the animal toxicology and pharmacology stud-
ies, manufacturing information to ensure that the company can produce and
supply consistent batches of the drug, and protocols for the proposed clinical
studies.
The IND is the precursor to human studies. In Phase 1, healthy volunteers
are tested. Phase 1 testing is for safety and dosage and typically takes about a
year. Once the drug is deemed safe in healthy volunteers, Phase 2 begins. The
drug is tested with people who have the condition being treated to determine
effectiveness, side effects, and dosage. As the drug proceeds from Phase 1
to Phase 2 and then Phase 3, greater amounts of the drug need to be man-
ufactured, increasing numbers of people are given the drug, and study costs
increase. Phase 1 might test 20 - 100 healthy volunteers, Phase 2, 100 - 500
patients, and Phase 3 may have 1,000 - 5,000 patients in the study. Phase 2
might take a couple of years. If a drug continues to look promising, it enters
Phase 3 of the drug development process. Phase 3 involves large-scale clinical
trials to demonstrate safety and efficacy over longer periods of time. The new
drug is compared against existing therapies and placebos. Phase 3 typically
takes about two to five years.