الفهرس 
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Abstract
1.1. Historical overview about drug discovery
Drug discovery and development has a long history and dates back to the early days
of human civilization. In those ancient times, drugs were not just used for physical
remedies but were also associated with religious and spiritual healing. Ancient papyrus
provided written records of early Egyptian medical knowledge. The Ebers papyrus (from
around 3000 BC) provided 877 prescriptions and recipes for internal medicine, eye and
skin problems, and gynecology. Another record, from the Kahun papyrus of around 1800
BC, detailed treatments for gynecological problems.
Medications were based mainly on herbal products such as myrrh, frankincense,
castor oil, fennel, sienna, thyme, linseed, aloe, and garlic. Some of the Greek medical ideas
were derived from the Egyptians, Babylonians, and even the Chinese and Indians. Castor
oil was prescribed as a laxative; linseed or flaxseed was used as a soothing emollient,
laxative, and antitussive. Other treatments include fennel plant for relief of intestinal colic
and gas, and asafetida gum resin as an antispasmodic. The greatest Greek contribution to
the medical field is perhaps to dispel the notion that diseases are due to supernatural causes
or spells. The Greeks established that diseases result from natural causes. The Romans also
extended the pharmacy practice of the Greeks. Dioscorides and Galen were two noted
physicians in Roman days. Dioscorides’s Materia Medica contains descriptions of
treatments based on 80% plant, 10% animal, and 10% mineral products. The Renaissance
period laid the foundation for scientific thoughts in medicinal preparations and medical
treatments. There were many advances made in anatomy, physiology, surgery, and medical
treatments, including public health care, hygiene, and sanitation. In 1796, Edward Jenner
successfully experimented with smallpox inoculations. This paved the way for the use of
vaccination against some infectious diseases. Louis Pasteur (1864) discovered that
microorganisms cause diseases, and he devised vaccination against rabies. This was
achieved through the use of attenuated rabies virus. Despite the advances made in the
1800s, there were only a few drugs available for treating diseases at the beginning of the
1900s. Penicillin was first isolated from Penicillium notatum in 1928 by Alexander
Fleming (Demian, 1999).
A series of different antibiotics were quickly discovered after penicillin came into
use. In 1940, Selman Waksman began searching for antibiotic compounds produced by soil
microorganisms (Greenwood, 2000). Since the 1960’s, there have been few discoveries of
new antibiotic drugs. The drugs developed since have mostly been chemical modifications
of existing drugs. These modifications have been very useful in treating infectious
diseases, leading to enhanced killing of pathogens, increased spectrum of action, reduced
toxicity, and reduced side effects. Unfortunately, since the 1970.