Pharmacology

1. Pharmacology Pharmacology is the study of the actions of drugs on the body and the way the body metabolizes drugs. The study of pharmacology includes the biochemical action on the body by drug and incorporates the knowledge and ideas from other scientific disciplines like biology, chemistry and physiology. In this section of the course, we will cover dosage forms and administration, pharmacology itself, pharmacodynamics and a quick overview of body systems like the cardiovascular system, skin, and endocrine systems

2. Source of Drugs • Natural Sources of Drugs • Drugs that originate from plants or animals • Examples: • Acetylsalicylic acid (ASA or Aspirin) originates from the bark of the willow tree. • Cocaine originates from the coca plant (Erythroxylum coca) • Morphine and Codeine originate from the Papaver somnifera plant • Digoxin comes from the Foxglove plant • Vincristine and Vinblastine are called vinca alkaloids and come from the periwinkle plant. • Niacin is a B vitamin (B3) is found in green vegetables • Cyanocobalamine is a B vitamin (B12) found in eggplant and meats • Insulin was originally isolated from pork (porcine) or bovine (cow) pancreas

3. Unusual Sources of drugs • Lepirudin (Refludan®) is an anticoagulant that is used in hospital to treat PE and DVT. Source: ? • The saliva of leeches known as Hirudo medicinalis. A leech is a blood sucking worm • Premarin® is conjugated estrogens used to treat vaginal bleeding and to treat post menopausal Sx in middle aged women. Source:? • The urine of pregnant mares • Captopril is an ACE inhibitor used to treat hypertension and CHF. Source:? • Brazilian arrowhead viper: a poisonous snake

4. Synthetic Drug Sources • Most synthetic drugs are really semi-synthetic in that the drug is chemically modified from a natural source. • Examples are: • Oxycodone (Oxycontin®) • Succinylcholine (Quelicin®) • Piperacillin/Tazobactam (Zosyn®) • Amoxicillin (Amoxil®)

5. Genetically Engineered Drugs • Recombinant DNA technology is a new modality that arised in the late 1970’s and early 1980’s. Greatly accelerated by the Human Genome Program completion in the late 1990’s. • Involves sequencing the gene for a human protein, carrying a vector for that gene (usually a virus), have the vector infect a host (usually a bacteria, E. Coli) and allowing the bacteria to mass produce the gene product for us to market. • Examples: • Recombinant human insulin . Recombinant insulin has almost completely replaced insulin obtained from animal sources (e.g. pigs and cattle) for the treatment of insulin-dependent diabetes ] • Recombinant human growth hormone. (HGH, somatotropin). Growth hormone is administered to patients whose are growth hormone deficient. • Recombinant blood clotting factor VIII. Recombinant factor VIII is a blood-clotting protein that is administered to patients with hemophilia • Recombinant hepatitis B vaccine. Prevention of hepatitis B infection is controlled through the use of a recombinant hepatitis B vaccine, which contains a form of the hepatitis B virus surface antigen that is produced in yeast cells.

6. Drug Nomenclature • Chemical name: the name of a drug according to its chemical structure. • Generic Name: the name given to a drug in agreement with the originally manufacturer and the FDA. Also called the nonproprietary name • Trade Name: the trademark name given to a drug by the original manufacturer. It is also called the proprietary name. No other manufacturer can legally use this name for their version of the drug

7. Dosage Formulations • The Dose formulation are different vehicles for the same drug in which each type of formulation, or vehicle, provides certain advantages and disadvantages

8. Solid Dose Forms • Tablets • Tablets are a solid dosage form of drug in which the drug is mixed with various active ingredients that provide a convenient way to give the drug. For the most part the inactive ingredient impart stability, color, taste, and bulk to the dose form • Advantages are: stability, convenience, and masking bad taste • Disadvantages are: difficulty in swallowing is taken orally, slow to act in the body

9. Tablets can be manufactured to be chewable, effervescent, enteric coated, or made into a controlled release dosage form • Some examples of different tablets types are: • Chewable vitamins and aspirin for adults • Enteric coated aspirin (Ecotrin®), Depakote ®, Videx EC (didanosine), Nexium®, Protonix ®, and Voltaren® EC. Enteric coated drugs are coated to protect either the stomach from the drug or the drug from the stomach. • Effervescent drugs most commonly release carbon dioxide. Example : Alkaseltzer® • Controlled release dosage forms where design to release the drug slowly over time in the GI tract. Examples: Toprol XL (metoprolol succinate), Tiazac ® CD (diltiazem CD), Calan® (verapamil CD), Procardia XL (nifedipine) and Glucotrol XL (glipizide). Controlled release dosage form should never be chewed!!

10. Capsule Dosage Forms • Capsule have many of the same advantages and disadvantages as tablets. • One advantage over tablets is the gelatin coating of the capsule is much easier to swallow that tablets

11. Ointments • Mixture of a drug into a semisolid vehicle base • Types of bases used: white petrolatum, lanolin, PEG base, waxes, and hydrophilic petrolatum • Oleaginous ointments can be used to carry drug and to be an emollient • Water soluble ointments carry drug and can be easily washed off is needed. • In general, ointments that carry drug are more potent than the cream version of the same drug • Liniments are ointment that possess a chemical agent that acts as a irritant. I.e. Methanol, camphor, etc

12. Creams • Vehicles in which a drug is mixed into a semisolid fluid medium. • Creams are emulsions that are either water in oil or oil in water based. • More popular because they are not as greasy as ointment bases • Lotion are similar to cream except water concentrations are higher

13. Liquid Dosage Forms • Solutions are aqueous mediums were the drug is completely dissolved in water. The drug is called the solute and the water is the vehicle or called the solvent. Commonly used to deliver medications like oral solution, enemas, irrigation solutions, IV solutions and others • Suspensions are aqueous mediums where the drug is not completely dissolved in the medium but is “suspended” in the medium to produce a mixture that is homogenized upon shaking. • Viscous Solutions are mediums that are similar to suspensions in that the drug is suspended into the medium. Include Jellies and mucilages (Metamucil®). Magmas and milks are in this category • Syrups are viscous solutions that have a high concentration of sugar. Simple Syrup USP is 85% sucrose in water

14. Non Aqueous Solutions • Hydroalcoholic solutions are a mixture of water and alcohol. • Elixir are mixture of alcohol, water, and sugar and a least one active ingredient. • The alcohol is meant to solubilize a drug that is normally not soluble in water alone and also to prevent the crystallization of sugar and to act as a preservative • Examples are Digoxin Elixir and Donnatal Elixir

16. Extractives • Extractives are liquids that are hydroalcoholic or purely alcohol solutions that contain a drug in high potency. • The crude drug found in plants usually are macerated, and pressed and dried. The material is exposed to an extractive which draws the active drug(s) into the extractive. • Tincture is a hydroalcoholic extractive of a drug where the potency of drug is equal to 100 mg of the crude ingredient per ml. i.e. Tincture of Opium 1 ml contains the equivalent of 10 mg morphine (this is how much morphine is in 100 mg of crude opium poppy) • Fluidextracts are 10x the potency of tinctures