2: drug sources

drugs are obtained from six major sources:

• - plant sources
• - animal sources
• - mineral / earth sources
• - microbiological sources
• - semi-synthetic / synthetic sources
• - recombinant DNA technology
  

"oldest source of drugs (materia medica)"

Plant sources

in using Plant sources, which parts are used

"all parts of the plants are used"

"source of digoxin and digitoxin (cardiac glycosides)"

"leaves: Digitalis purpurea (foxglove)"

gives atropine

"leaves: Atropa belladona (deadly nightshade)"

"source of morphine (opioid)"

"flowers: Papaver somniferum(poppy) 
"

"gives

vincristine and vinblastine"

"FLOWERS: Vinca rosea(periwinkle)

"

Inhibits microtubule formation, halting mitosis at metaphase

Vincristine

disrupts microtubule assembly, causing mitotic arrest

Vinblastine

"give anthracine (purgative)"

"fruit: Sennapods
"

"give physostigmine (parasympathomimetic agent)"

"Calabar beans
"

"gives strychnine (CNS stimulant)"

"seeds of Nux vomica
"

"give emetine (emetic agent)"

"Ipecacuanha roots
"

"roots give reserpine (anti-hypotensive agent)"

"Rauwolfia serpentina roots
"

"gives quinine and quinidine (antimalarial drugs)"

"Cinchona bark
"

"gives hyoscine, an anticholinergic drug"

"Hyoscyamus niger bark
"

"gives tubocurarine(skeletal muscle relaxant during anaesthesia)"

"stem of Chondrodendron tomentosum

"gives hCG (human chorionic gonadotropin) used for the treatment of infertility"

urine of pregnant women

"is a source of thyroxine, used in hypertension"

sheep thyroid

used to treat iron deficiency anemia

iron

used as antiseptic in wounds

iodine

"used as supplement or as zinc oxide paste in wounds or in eczema"

zinc

used in syphilis

mercurial salts

difference between Synthetic and semi-Synthetic sources

"

• Synthetic sources- when the nucleus and the chemical structure of

a drug from a natural source is altered

Semi-synthetic sources- when the nucleus of a drug from a natural

source is retained but the chemical structure is altered
"

examples of synthetic and semi-synthetic drugs

"

• synthetic - emetine bismuth iodide (treatment for amoebic dysentery
• semi-synthetic drugs- apomorphine (emetic), methyl testosterone
  

"

"gives penicillin (antibiotic)"

Penicillium notatum

"gives streptomycin (antibiotic)"

Actinobacteria

"give aminoglycosides such as gentamicin and tobramycin"

"Streptomyces spp. and Micromonospora spp"

"Recombinant DNA Technology involves cleavage of DNA by …"

enzyme restriction endonuclease

• advantages of Recombinant DNA Technology

"

• - huge amounts of drugs produced
• - drugs can be obtained in pure form
• - less antigenic
  

"

disadvantages of Recombinant DNA Technology

"

• - well-equipped lab required
• - highly-trained staff required
• - technique is complex and complicated
  

"

examples of drug from  Recombinant DNA Technology

"erythropoietin, hormones, enzymes, vaccines"

"process of bringing a novel drug from “bench to bedside”"

Drug Development