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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.

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• 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.

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Pharmacology

Pharmacokinetics

Dose of Drug [Drug] in Target organ Over time

Absorption

Distribution

Biotransformation

Excretion

Pharmacodynamics

Mechanism & Magnitude of drug effect

Receptor Binding

Signal Transduction

Physiologic Effect

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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

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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

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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)

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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

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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?

Crude-

Pure-

Phamaceutical-

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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.

Drug Preparations•Crude drug preparations

•Drying, pulverizing•Extraction; Alcohol, hot water>Coffee, Tea, Opium

•Pure drug compounds•Morphine, Insulin

•Pharmaceutical preparations

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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

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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-

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• 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

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Routes of drug administration• Enteral

– Sublingual/buccal

– Oral PO (per os)

– rectal

• Parenteral– Intravenous

– Intramuscular, subcutaneous

– Intrathecal

• Transdermal• Inhalation• Topical

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Drug names

• Chemical

• Nonproprietary (generic)

• Proprietary, trade name, brand name