Basic principles and introduction to pharmacology

1. BASIC PRINCIPLES OF
PHARMACOLOGY
LECTURE 1 & 2
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2. Learning Objectives:
• To learn and understand terminologies related to pharmacology.
• To briefly understand pharmacokinetics.
• To know different nomenclatures of drug.
• To understand different methods of classifying drugs.
• To learn different dosage forms of drugs.
• To know different components in dosage forms.
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3. What is pharmacology?
• Pharmacology is the science of drugs.
• It deals with the interaction of exogenously administered chemicals
(drugs) with living systems.
• Two main areas
• Pharmacokinetics
• Pharmacodynamics
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4. What is pharmacology?
• Drug composition and properties
• Synthesis & drug design
• Molecular & cellular mechanisms
• Organ/systems mechanisms
• Signal transduction /cellular
communication
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• Molecular diagnostics
• Interactions,
• Chemical biology
• Therapy
• Medical applications
• Antipathogenic capabilities.

5. Drug
• French: Drogue – a dry herb.
• Active chemical entity present in a medicine that is used for
diagnosis, prevention, treatment or cure of a disease.
• WHO definition: Drug is any substance or product that is used or is
intended to be used to modify or explore physiological systems or
pathological states for the benefit of the recipient.
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6. Pharmacokinetics
• Greek: Kinesis – movement
• What the body does to the drug.
• Refers to movements of drug in and alteration of the drug by the
body.
• Includes absorption, distribution, binding/localization/storage,
biotransformation and excretion of the drug.
• ADME
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8. Pharmacodynamics
• Greek: dynamis – power.
• What the drug does to the body.
• Includes physiological and biochemical effects of drugs and their
mechanism of action at macromolecular / subcellular / organ system.
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10. Drug Nomenclature
• Drug names – 3 categories:
• Chemical name
• Non-proprietary name
• Proprietary (Brand)
name
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11. 1. Chemical name:
• Describes the substance chemically.
Eg: 1-(isopropylamino)-3-(1-naphthyloxy) propan-2-ol
Chemical name of propranolol
• Not suitable for prescribing.
• Code name may be assigned by the manufacturer for convenience &
simplicity before an approved name is coined.
Eg: RO 15-1788 (for flumazenil)
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13. 2. Non-proprietary / generic name:
• Name accepted by a competent scientific body such as the United
States Adopted Name (USAN) council.
• rINN – Recommended International Nonproprietary Name –
agreement for newer drugs for uniform usage of non-proprietary
name.
• Few older drugs – more than one non-proprietary name.
Eg: Meperidine (USA) & Pethidine (UK, India)
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14. 2. Non-proprietary / generic name:
• Until the drug is included in a pharmacopoeia, the non-proprietary
name is also called as approved name.
• After its inclusion in the official publication, it becomes the official
name.
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16. 3. Proprietary / brand name:
• Name assigned by the manufacturer and it is the trademark.
• One drug → may have multiple proprietary name.
• Different brand names in different countries.
• Same manufacturer, same drug → market with different
brand names in different countries.
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17. 3. Proprietary / brand name:
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19. Classification of drugs
Drugs
By pharmacological effect
By chemical structure
By target system
By target molecule
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20. 1. By pharmacological effect:
• Depending on the drugs biological or pharmacological effect.
Eg: analgesics, antihypertensives, antibiotics, anti-
asthmatics, etc.,
• Drugs included in each class will be numerous & varied
chemical structure.
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21. 2. By chemical structure:
• Drugs having a common chemical skeleton are grouped
together.
Eg: penicillins, barbiturates, opiates, steroids, etc.,
• This classification is useful sometimes, because the biological
activity & MOA is same for the structures involved.
Eg: Penicillins → antibiotics
Barbiturates → sedative & hypnotic
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22. 2. By chemical structure:
• There are few exceptional classes too.
Eg: Steroids → similar chemical structure → but different
effects on the body.
Sulfonamides → similar skeleton → few are antibacterial,
hypoglycaemics.
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23. 3. By target system:
• According to the target system, which the drug affects.
Eg. Neurotransmitter synthesis
Neurotransmitter release
• This method may give a specific classification, but still
diversified with more number of targets and different classes
of drugs.
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24. 4. By target molecules:
• According to the molecular target with which they involve.
Eg. anticholinesterases
carbonic anhydrase inhibitors
COX inhibitors
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25. Physicochemical properties of drug
The ability of a chemical compound to elicit a pharmacological/
therapeutic effect is related to the influence of various physical and
chemical (physicochemical) properties of the chemical substance on the
bio molecule that it interacts with.
• Eg:
Physical property → responsible for its action.
Chemical property → extracellular reactions.
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27. Dosage forms - overview
• Definition: Dosage forms are the carriers through which drug molecules
are delivered to sites of action within the body.
• Need:
• Accurate dose.
• Protection e.g. coated tablets, sealed ampules.
• Protection from gastric juice.
• Masking taste and odour
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28. Dosage forms - overview
• Need:
• Placement of drugs within body tissues.
• Sustained release medication.
• Controlled release medication.
• Optimal drug action.
• Insertion of drugs into body cavities (rectal, vaginal)
• Use of desired vehicle for insoluble drugs
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30. Excipients / Additives
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31. Dosage forms – Classification (based on physical state)
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32. Dosage forms – Classification (based on ROA)
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34. Routes of drug administration - overview
• LOCAL ACTION:
• Topical
• Skin – ointment, cream, lotion, paste, powder, dressing, spray,
etc.,
• Mucous membrane
• Mouth & pharynx – paints, lozenges, mouthwashes, gargles
• Eyes, ear & nose – drops, ointments, irrigation, nasal spray
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35. Routes of drug administration - overview
• GIT – non absorbable oral drugs – sucralfate, magnesium
hydroxide
• Bronchi & lungs – inhalations, aerosols
• Urethra – jelly
• Vagina – pesseries, vaginal tablets, inserts, cream, powders,
douches.
• Anal canal – ointment, suppositories.
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36. Routes of drug administration - overview
• Deeper tissues – intra-articular injection, intrathecal injection,
retrobulbar injection.
• Arterial supply – nearby intra-arterial injection. Eg. Angiography.
• SYSTEMIC ROUTES:
• Oral
• Sublingual or buccal
• Rectal
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37. Routes of drug administration - overview
• Cutaneous – TDS
• Inhalation
• Nasal
• Parenteral – s.c., i.m., i.v., i.d.,
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