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.

2 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.

3 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

4 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

5 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

6 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)

7 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

8 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-

9 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

10 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

11 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-

12 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

13 Routes of drug administration Enteral –Sublingual/buccal –Oral PO (per os) –rectal Parenteral –Intravenous –Intramuscular, subcutaneous –Intrathecal Transdermal Inhalation Topical

14 Drug names Chemical Nonproprietary (generic) Proprietary, trade name, brand name