Download Document

59-291 Section 1
Introduction to Pharmacology
Humans have been treating diseases with substances around them for
over 4000 yrs.
These “drugs’ were chosen empirically (based on experience).
The science of pharmacology is ~150 yrs old.
This is because the knowledge of the biochemical and physiological
mechanisms by which drugs produce their physiological effects has
been gained in the recent past.
1
• Phase I: Superstition and Experience (Empiricism)
• Phase II: Using plants/animals/ minerals to treat
diseases
– Greeks; e.g. Dioscorides: described 600 plants
– Islamic physicians; e.g. Avicenna, Razi: Herbal
medicine
– Herbal medicine is still being practiced in many areas
• Phase III: Scientific
– Understanding physiopathology of diseases
– Rational for using drugs
– Isolation of pure drug compounds from natural sources;
e.g. Morphine from Opium
Pharmacology- The science concerned with the
interaction of chemical substances with living
cells, tissues and organisms and the
mechanisms by which drugs counteract the
manifestations of disease or affect fertility.
2
Pharmacology
Pharmacokinetics
Dose of Drug
Pharmacodynamics
[Drug] in
Target organ
Over time
Mechanism
& Magnitude
of drug effect
Absorption
Receptor Binding
Distribution
Signal
Transduction
Biotransformation
Excretion
Physiologic Effect
3
Toxicology- Science of poisons and toxicity i.e. the harmful
effects of drugs
- dose X drug therapeutic
- dose >X drug becomes toxic
-this might also be caused by drug interactions
Pharmacotherapeutics- The science concerned with the use of
drugs in the treatment of disease.
-explaining the molecular mechanism for the effect of drug on
the body as well as the relationship between dose and drug
response (Dose-response curves)
-Clinical trials: used to determines the efficacy and safety of
drug therapy in human subjects
4
More Definitions
Pharmacy- Profession concerned with the preparation, storage
dispensing and proper utilization of drug products.
Pharmacognosy- Isolation and characterization of drugs from
natural sources including: Plants, animal tissues, microbes, and
minerals
Medicinal Chemistry- Design and chemical synthesis of drugs
Pharmaceutical chemistry (Pharmaceutics) - concerned with the
formulation and chemical properties of pharmaceutical products,
dosage form of drugs; tablets, capsules, liquid solutions, and
aerosols
5
Drug sources and preparation
• Drug- (fr. Drogue- dried herbs), medication,
medicament: Substance administered to humans
and animals for diagnosis or treatment of disease
• Natural sources of drugs:
– Plants: Alkaloids >>Morphine
– Microbes: Antibiotics >> Penicillin,
streptomycin
– Animal tissues: Hormones>> growth hormone
– Minerals: Lithium (Psychotherapy)
6
Synthetic drugs- Although a drug is derived from natural sources,
today it is more practical to synthesized in a laboratory.
-alterations are made on the naturally found structure of the drug
to improve its effect and to improve the finances of
pharmaceutical companies
Structure function relationships- (a relationship between the
chemical structure and the pharmacologic activity)
guide the discovery of new drugs
7
Recently chemists have developed
computer programs to facilitate the design of
new drugs. These programs help design
chemicals that fit to the 3-D conformation of
the receptor.
-led to the discovery of HIV protease
inhibitors, ACE inhibitors etc.
Drug Preparations- What are the differences?
CrudePurePhamaceutical8
Drug Preparations
•Crude drug preparations
•Drying, pulverizing
•Extraction; Alcohol, hot
water>Coffee, Tea, Opium
•Pure drug compounds
•Morphine, Insulin
•Pharmaceutical preparations
Figure 1-2 Types of drug preparations. A crude drug preparation retains
most or all of the active and inactive compounds contained in the natural
source from which it was derived. After a pure drug compound (e.g.,
morphine) is extracted from a crude drug preparation (in this case, opium),
it is possible to manufacture pharmaceutical preparations that are suitable
for administration of a particular dose to the patient
.
9
Pharmaceutical preparations
(dosage forms)
• Suitable for administration of specific dose
of a drug to a patient
• Tablets and capsules
– Ingredients; fillers, lubricants, adhesives,
disintegrants
– Enteric coating: disintegrates in alkaline
intestine
– Sustained-release products
10
Sustained release or extended release products
What are the 2 methods that extend
the release of a drug?
•Controlled diffusion>> rate
controlling membrane
•Controlled dissolution>> inert
polymers
Transdermal patches-
11
• Solutions and suspensions
–
–
–
–
Formulated for oral, parenteral administration
Convenient method for pediatrics
Syrups: Sweetened aqueous solutions
Elixirs: Sweetened alcoholic solutions
• Skin patches
• Aerosols: respiratory disorders
– Nasal spray
• Ointments, creams
– Topical application on skin/mucous membranes
• Lotions:
– oil in water emulsion; to treat dermatologic conditions
• Suppositories:
– Drugs inside a solid base that melts at body temperature
12
Routes of drug administration
• Enteral
– Sublingual/buccal
– Oral PO (per os)
– rectal
• Parenteral
– Intravenous
– Intramuscular, subcutaneous
– Intrathecal
• Transdermal
• Inhalation
• Topical
13
Drug names
• Chemical
• Nonproprietary (generic)
• Proprietary, trade name, brand name
14