Pharmacognosy

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Pharmacognosy

• Pharmacology 49.222
• Bill Diehl-Jones RN, PhD
• Faculty of Nursing and Department of Zoology

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Agenda

• A Zen Review
• Pharmacognosy (Sources of Drugs)
• Drug Development
• Uses of drugs

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Where do Drugs Come From

• Plants
• Animals
• Minerals
• Synthetic
• chemically-purified
• recombinant

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Plant Sources

• Earliest source
• NB Alkaloids
• react with acids to form salts
• salts are soluble in body fluids
• Eg atropine, caffeine, nicotine

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More Plant Sources

• Glycosides
• eg digoxin
• Gums
• polysaccharides from seaweeds
• Resins
• pine tree sap
• irritants
• Oils
• volatile(pepermint)
• fixed (castor oil)

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Animal Sources

• Hormones
• insulin
• Oils and fats
• cod-liver oil
• Enzymes
• pancreatin
• Vaccines
• killed, modified or attenuated viruses

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Mineral Sources of Drugs
COOH
OH

• Eg Coal Tar
• yields the following
• salicylic acid
• aluminum hydroxide
• sodium chloride

Salicylic Acid
COOH
OCOCH3
Acetylsalicylic Acid
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Laboratory Produced Drugs

• Organic
• C,O,H,N -containing
• eg penicillin
• Inorganic
• sulfonamide antibiotics
• oral contraceptives
• Recombinant drugs

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And what, you ask, is a recombinant drug?!
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Recombinant Drugs

• These are drugs produced by means of recombinant
  DNA technology
• It all starts with a gene that codes for a
  specific protein ...

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How a recombinant drug is made ...
A Bacterium
cDNA(codes for a protein)
Plasmid (a circular bit o DNA)
A Protein
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Example of a Recombinant DrugInsulin

• Most insulin is now recombinant
• why might this be a good thing?
• Consists of two chains (A and B)
• A and B chains joined chemically

A
S S
B
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How Are New Drugs Developed?
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Four Phases

• Phase I
• study with a small of healthy volunteers
• can involve pharmacologist/nurse
• Phase II
• small number of individuals with disease are
  given drug

• Phase III
• larger population
• a placebo is used
• physicians/patients are blinded
• Phase IV
• drug company can market drug
• company does surveillance

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Expedited Drugs

• Eg AIDS drugs
• Can go from phase II or phase III to qualified
  patients
• Other drugs may be given to patients before full
  approval on compassionate grounds

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Orphan Drugs

• Some drugs never make it to market
• Why?
• Limited market
• high-risk
• However, some patients can benefit from the drug
  (eg Botox)
• tax credits for companies to produce drug

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Pharmacotherapeutics

• The use of drugs to treat disease ...

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Three General Uses of Drugs

• Prevention
• Diagnosis
• Treatment

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Drugs for Prevention

• Vaccinations
• Hepatitis B vaccine (inactivated)
• made from recombinant DNA
• eg Energix
• active immunity
• Hepatitis B immune globulin (HBIG)
• given if people do not respond to Energix
• passive immunity

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Drugs for Diagnosis

• Radiologic dyes
• Barium
• Technicium
• iodine
• Hormones
• Cosynotropin
• stimulates adrenal gland to produce cortisol
• used to Dx adrenal abnormalities

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Drugs for Treatment

• Range from antineoplastic drugs to laxatives
• Take your pick!

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Factors Influencing Choice of Therapy

• Does it work?
• Risk/benefit for patient
• Patient compliance
• Cost