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Introduction to Medicinal Chemistry. Chapter 1 Part 1. What is medicinal chemistry?. The science that deals with the discovery or design of new therapeutic chemicals and the development of these chemicals into useful medicine. What is “medicine”?. Drugs, pharmaceutics Media distinction
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Introduction to Medicinal Chemistry Chapter 1 Part 1
What is medicinal chemistry? • The science that deals with the discovery or design of new therapeutic chemicals and the development of these chemicals into useful medicine
What is “medicine”? • Drugs, pharmaceutics • Media distinction • A compound that interacts with a biological system, and produces a biological response (ideally desired and positive)
“Good” vs. “Bad” Drugs • No medicine has only benefits or drawbacks • Morphine • Excellent analgesic • Addictive, tolerance • Respiratory depression • Barbiturates • Depressants, sedatives, anesthetics • Surgery • Overdoses fatal (Pearl Harbor)
Heroin • Known clinically as Diamorphine • One of the best painkillers • 1898: on market • 1903: withdrawn (addictive properties) • Today: still used
Aspirin • 400 BC: Hippocrates • Chew bark of willow tree for pain (childbirth and eye infections) • Active component of willow bark = salicin
Cocaine • South American coca bush • Plant used as a stimulant, mystical/religious reasons • Isolated 1880’s • Anesthetic in dentistry • Addiction: Freud • Used for depression; other drug addiction • Drug development based on structure • Procaine (Novocain)
Everyday drugs • Still produce a response; many are addictive • Caffeine • Sugar • Nicotine • Alcohol • Food additives • Vitamins • Herbs • Basil: 50 potential carcinogens • Cultural aspects
“Good” vs. “Bad” Drugs • Depends on: • Dosage • Almost anything in excess will be toxic • Chronic exposure • Measure of safety of drug = therapeutic index
Therapeutic index • Measure of a drug’s beneficial effects at low dose vs. harmful effects at high dose • Comparison of dose levels which lead to toxic effects to dose levels which lead to maximum therapeutic effects • High therapeutic index = large margin of safety • Marijuana = 1000 • Alcohol = 10 • Does not take chronic use into account
Classification of drugs • Four main groups (overlap) 1. By pharmacological effects • Analgesics, anti-asthmatics, antipsychotics, etc. • Large and varied assortment of drugs • Many mechanisms of action 2. By chemical structure • Penicillins, steroids • Common skeleton • Functions may be similar or different
Classification of drugs 3. By target system • Antihistamines • Affect a target system (synthesis, release, receptor) • Variety of structures due to large number of stages in system 4. By target molecule or site of action on target • Very specific classification • Expect structural similarity and common mechanism • Easy to classify compounds too narrowly and miss possible positive side effects (new uses for the compound) • Zyban • Viagra