Drug Sources and Dosage Forms Flashcards
Schedules of Controlled Substances
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Plant drug sources examples
Alkaloids are organic compounds combined with acids to make a salt. Nicotine, morphine sulfate, and atropine sulfate are examples of these chemical compounds. An important cardiac glycoside is digoxin. Digoxin is made from digitalis, a derivative of the foxglove plant.
Animal drug sources examples
Animal sources, such as the body fluids and glands of animals, can act as drugs. The drugs obtained from animal sources include enzymes such as pancreatin and pepsin. Hormones such as thyroid and insulin are also from animal sources.
Mineral drug sources
Minerals from the earth and soil are used to provide inorganic materials unavailable from plants and animals. They are used as they occur in nature.
Examples include iron, potassium, silver, and gold, which are used to prepare
medications. Sodium chloride (table salt) is one of the best-known examples in this category. Gold is used to prevent severe rheumatoid arthritis, and coaltar is used to treat seborrheic dermatitis and psoriasis.
Synthetic drug sources
New drugs may come from living organisms (organic substances) or nonliving materials (inorganic substances). These drugs are called synthetic or manufactured drugs. They are created through the application
of chemistry and biology. Because they are not found in nature, these medications come from artificial substances.
Common examples of synthetic drugs include meperidine (Demerol®), sulfonamides, and oral contraceptives. Certain organic drugs such as penicillin are semisynthetic and are made by altering their natural compounds or elements. Some
drugs are both organic and inorganic, such as propylthiouracil, which is an antithyroid hormone.
Penicillin is produced by…
Penicillin is produced by strains of Penicillium notatum or Penicillium chrysogenum when inoculated into a suitable nutrient medium.
Engineered drug sources
Th e newest area of drug origin is gene splicing or genetic engineering.
The newer forms of insulin for use in humans have been produced withm this technique. Other engineered drugs include: tissue plasminogen activator, growth hormones, cancer drugs, and drugs that combat HIV.
Th e replacement of missing or nonfunctional genes is an emerging area of
genetic engineering.
Solid Drugs - tablets
The various forms of tablets include chewable, sublingual, buccal, enteric-coated, and buffered tablets.
Chewable tablets must be chewed. They contain a flavored or sugar base. Chewable tablets are commonly used for antacids and antiflatulents, and for children who cannot swallow medication.
Sublingual tablets must be dissolved under the tongue for rapid absorption. An example is nitroglycerin for angina pectoris. Buccal tablets are placed between the cheek and the gum until they are dissolved and absorbed.
An enteric-coated tablet has a special
coating to protect against stomach acid, allowing the drug to dissolve in the
alkaline environment of the intestines.
A buffered tablet can prevent ulceration
or severe irritation of the stomach wall. Antacids have been added to reduce
irritation to the stomach by the active ingredients. Some tablets are coated with
a volatile liquid that is meant to dissolve in the mouth, such as antacid tablets.
Solid Drugs - capsules
A capsule is a medication dosage form in which the drug is contained in an
external shell.
Capsule shells are usually made of hard cylindrical gelatin and enclose or encapsulate powder, granules, liquids, or some combinations of these. Liquids may be placed in soft gelatin capsules, such as
vitamin E capsules and cod liver oil capsules. They are used when medications
have an unpleasant odor or taste.
Capsules can be pulled apart, and the entire
contents can be added as powder to food for individuals who have difficulty
swallowing.
Some forms of capsules come with a controlled-release dosage and
are used over a defined period of time. These are called sustained-release (SR)
or timed-release capsules. These drugs should never be crushed or dissolved,
because this would negate their timed-release action.
