Drug- definition, origin, nomenclature. Drug form and drug product- definition. Drug preparations.
Definition:
A drug is a substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease. It can also refer to any substance (other than food) that affects the structure or function of the body when introduced into a living organism.
Origin of Drugs:
1. Natural Sources:
Drugs derived from nature include:
- Plants: Many drugs are extracted from plants, such as morphine from the opium poppy and aspirin from willow bark.
- Animals: Certain hormones and enzymes come from animal tissues, such as insulin (previously extracted from pigs and cows, now mostly produced through recombinant DNA technology).
- Microorganisms: Antibiotics like penicillin are derived from fungi, while streptomycin comes from bacteria.
- Minerals: Some inorganic compounds have medicinal properties, such as lithium for bipolar disorder and magnesium sulfate as a laxative.
2. Synthetic Sources:
- Chemical Synthesis: Drugs developed in laboratories to create new compounds or modify existing ones for improved efficacy and safety. Examples include aspirin and many antidepressants.
- Semi-Synthetic: Naturally occurring compounds that are chemically modified to enhance their effectiveness. Example: semi-synthetic penicillins (ampicillin, amoxicillin).
3. Biotechnological Sources:
- Recombinant DNA Technology: Used for producing hormones, antibodies, and vaccines such as human insulin and monoclonal antibodies.
- Gene Therapy: Involves introducing genetic material into cells to treat genetic disorders or cancers, such as in CAR-T cell therapy.
Drug Nomenclature:
Drugs have three main names:
- 1. Chemical Name: Describes the precise molecular structure of the drug.
- Example: N-acetyl-p-aminophenol (Paracetamol).
- 2. Generic Name: The official, non-proprietary name given by international organizations like the United States Adopted Names (USAN) Council.
- Example: Paracetamol (also known as Acetaminophen in the US).
- 3. Brand Name (Trade Name): The name given by a pharmaceutical company for marketing purposes.
- Example: Panadol, Tylenol (for Paracetamol).
Drug Form (Dosage Form):
The physical form in which a drug is produced and administered. It determines the route of administration, absorption rate, and therapeutic effect.
- 1. Solid Forms: Tablets, Capsules, Powders.
- 2. Liquid Forms: Solutions, Suspensions, Emulsions, Syrups.
- 3. Semi-Solid Forms: Creams, Ointments, Gels, Pastes.
- 4. Gaseous Forms: Inhalers, Aerosols.
Drug Product:
A finished dosage form that contains the active drug ingredient(s) and excipients (inactive substances) required for stability, absorption, and patient compliance.
Examples of Drug Products:
- 1. Tablets: Solid dosage forms containing active ingredients and excipients.
- 2. Injectables: Sterile solutions or suspensions administered via injection.
- 3. Topical Preparations: Creams, ointments, and lotions applied to the skin.