DRUG PROERTIES.pptx.....................

PHARMACOLOGY FOR
BPC 2.2/BNS 2.3
JULY 2024
Dr. Peter Nuwagira, PhD fellow, MSc,B.Pharm,MPS

SESSION OBJECTIVES
• Define relevant terms
✓ Pharmacology
✓ Drug
✓ Therapeutics
✓ Pharmacokinetics
✓ Pharmacodynamics
✓ Pharmacy
• Describe drug nomenclature
• Advantages and disadvantages of different drug nomenclature
• Explain how drugs are classified
• Define a receptor
• Know where drugs exact their action
• Define agonist,antagonist ,partial agonist, inverse agonist, efficacy et

What is Pharmacology?
The term pharmacology comes from two Greek words:
• pharmacon - drug or medicine
• logos - meaning science/study.
• Pharmacology can be defined as the study of the effects of drugs/chemicals on the
function of living systems
It focuses particularly on how drugs/ chemicals help to:
• Prevent diseases
• Correct physiology of living tissues
• Cure or minimize diseases, etc

What is a drug?
A chemical substance of known structure, other than a nutrient or an essential
dietary ingredient, which, when administered to a living organism, produces a
biological effect
Substances used to cure, control, prevent or diagnose a disease
Drugs can be for therapeutic use (treatment), prophylactic use (prevention),
or diagnostic use (diagnosis)
❑ Drugs may be synthetic chemicals, chemicals obtained from plants or
animals, or products of genetic engineering

SOURCES OF DRUGS
1. Animals: hormones (e.g. insulin, heparin), enzymes (streptkinase, amylase, lactase, protease etc)
2. Plants: e.g.
a. Atropine:Atropa belladona
b. Morphine: Papava seminiferum
c. Quinine: cinchona bark
3. Inorganic e.g. Li, Ca, Mg, K, etc
4. Chemical synthesis: most drugs are recombinant drugs
5. Microorganisms: e.g. penicillin
6. Marine (omega-3 fatty acids from fish oil and algae, vidarbine derived from the sponge Tethya crypta,
Ziconotide from the venom of the cone snail conus magus etc)

NAMING OF DRUGS
❑ Drugs have 3 names
1. Chemical name: name indicating drug’s chemical structure e.g. 4 acetaminophenol,
acetlysalicylic acid.
2. Generic name: is the official name. a.k.a non-proprietary name e.g. paracetamol
3. Trade name: name given to the drugs by manufacturers.A.k.a proprietary or commercial
name
1. e.g. panadol, tylenol, kamadol, renidol, etc
An example of these three names, using a well known prescription drug is as follows:
Chemical name — 7-chl oro-1,3-di hydro-1- methyl-5-phenyl-2H-1,4-benzodiazepin-2-one;
Generic name — diazepam ;Brand name —Valium

Nomenclature of drugs
• Non proprietaryVs drugs Proprietary drugs
• Approved nameVs Brand name
• Generic name VsTrade name
• Official nameVs Commercial name
Dosage forms:
Form of the drug by which it is administered
•Liquid
•Solid
•Semisolid
•Gas

CLASSIFICATION OF DRUGS
•Chemical structure, e.g. steroids, barbiturates, benzodiazepines, glycosides
•Principal pharmacological effect, e.g. bacteriostatic, diuretic, sedative,
anesthetic, analgesic, purgative, antiemetic, anthelmintic, etc
•Physiological effect, e.g. parasympathomimetic, adrenergic, β-blocker,
neuromuscular blocker.
•According to the body system e.g cardiovascular drugs, renal drugs

The Physical Nature of Drugs
• To interact chemically with its receptor, a drug
molecule must have the appropriate size, electrical
charge, shape, and atomic composition.
•At room temp drugs exist as:
• Solids:-Solid drugs include:- tablets, pills, plaster, capsules, caplets,
gelcaps, powder, granules, troches, or lozenges. e.g., aspirin, atropine etc
Physical properties

• Liquids:- Syrup, Solution, Spirit, Elixir, Tincture, Fluidextract,
Liniment: eg, nicotine, ethanol
• Gaseous: Nitrous oxide, halothane, oxygen etc
• These factors often determine the best route of administration.

• 2. Drug Size
• Small size favors absorption
• Molecular size of drugs varies from very small (lithium ion,
MW 7) to very large (eg, alteplase [t-PA], a protein of MW
59,050).
• Most drugs in clinical practice have MWs between 100
and
1000.
• Very large drugs (usually proteins) must often be
administered directly into the compartment where they
have their effect. e.g. alteplase(clot-dissolving enzyme)
• Drugs MW larger than 1000 do not diffuse readily between
compartments of the body.
• Drug-Receptor Bonds
• Drugs interact with receptors by means of chemical forces
or bonds.
• These bonds include:-
• Covalent,
• Electrostatic, and

•Covalent bonds are very strong and in many
cases not reversible under biologic
conditions.e.g aspirin(acetylsalicylic acid)
inhibits cyclooxygenase enzyme by forming
covalent bond.
•Platelet aggregation–blocking effect of
aspirin lasts long & is reversed only by the
synthesis of new enzyme in new platelets, a
process that takes several days.
•Another example is the DNA-alkylating
agents
used in cancer chemotherapy.
• Electrostatic bonds are relatively strong but are
weaker than covalent bonds.
•Hydrophobic bonds are quite weaker.

•Drug Shape
•The shape of a drug molecule permit it to bind to
its receptor site.
•Drug’s shape should be complementary to that
of the receptor site in the same way a key is
complementary to a lock.

ROUTES OF DRUG
ADMINISTRATION
1) Enteral
• Oral
• Sublingual
2) Parenteral
• Intravenous (IV)
• Intramuscular
(IM)
• Subcutaneous
(SC)
3) Other
• Inhalation
• Intranasal
• Intrathecal/
intraventricular
• Topical
• Transdermal

APPROPRIATE ROUTES OF DRUG ADMINISTRATION
• Choice of appropriate route depends on drug &
patient related factors.
1) Physical and chemical properties of the drug
(solid/liquid/ gas; solubility, stability, pH,
irritancy).
2) Site of desired action-localized or generalized
3) Rate and extent of absorption of the drug from
different routes.
4) Effect of digestive juices and first pass
metabolism on the drug.
5) Rapidity with which the response is desired
( routine treatment or emergency).
6) Accuracy of dosage required (i.v. and
inhalational can provide fine tuning).
7) Condition of the patient (unconscious,
vomiting)

Oral route
•It is safer, more convenient, does not need
assistance, noninvasive, often painless, the
medicament need not be sterile.
•Suitable for solid dosage forms (powders,
tablets, capsules) and liquid dosage forms
(elixirs, syrups, emulsions, mixtures)

An “ideal” oral drug must be able to:
• dissolve
•survive a range of pHs (1.5 to 8.0)
• survive intestinal bacteria
•cross membranes
•survive liver metabolism
•avoid active transport to bile
•avoid excretion by kidneys
•partition into target organ
•avoid partition into undesired
places (e.g. brain)

Limitations of oral route of administration
1) Action of drugs is slower and thus not for
emergencies.
2) Unpalatable drugs (chloramphenicol) difficult
to administer.
3) May cause nausea and vomiting (emetine).
4) Cannot be used for
uncooperative/ unconscious/
vomiting patients.
5) Absorption of drugs may be variable and
erratic; certain drugs are not absorbed
(streptomycin)
6) some drugs are destroyed by digestive
juices (penicillin G, insulin) or in liver
(GlycerlyTrinitrate, testosterone, lidocaine).

Enteric Coated Tablets
•The drugs which are destroyed by the
gastric juices in the stomach, are coated
with keratin, shellac and cellulose acid
phosphate.
•useful in:
Preventing gastric irritation and
alteration of the drug in the stomach.
To get the desired concentration of
the drug in intestine.
To delay the absorption of the drug.

Time Release/Sustained Release Capsules
•It is a useful solid dosage form of drug,
where the particles of the drug dissolve at
different time intervals.
•Advantages of time-release preparations are:
•Reduction in the frequency of
administration of drug.
•Maintenance of therapeutic effect for longer
time.
•To some extent ↓ incidence of undesired
effects.
•Appropriate for drugs with short half lives
(less than 4 hours).

Sublingual or buccal route
•The tablet is placed under the tongue
•Only lipid soluble and non-irritating
drugs can be administered.
•The advantages of this routes are:
•Rapid onset of action.
•The degradation and metabolism of
the drugs in the stomach and liver is
avoided

Parenteral routes
• (par = beyond, enteral = intestinal)
• Take the drug directly into the tissue fluid or blood
without having to cross the intestinal mucosa.
• The advantages of parenteral routes are:
• Rapid action of drug.
• Can be employed in unconscious/uncooperative
patients.
• Drugs, which are modified by alimentary juices and
liver can be given by this route.
• Drugs, which are not absorbed in small intestine or
irritate the stomach can be administered by this
route.
• There are no chances of interference by food

• Disadvantages are:
• Less safe, more expensive.
• Inconvenient (painful) for the patient.
• Self medication is difficult.
• Chances of local injury at the site of injection.
(i) Intramuscular (i.m.)
• The drug is injected in one of the large skeletal
muscles-deltoid, triceps, gluteus maximus,
rectus femoris, etc.
• Muscle is less richly supplied with sensory nerves
(mild irritants can be injected) and is more vascular
(absorption of drugs in aqueous solution is faster).
• Depot preparations (oily solutions/ aqueous
suspensions) can be injected by this route.
• Sh’d be avoided in anticoagulant treated patients,
b’se it can produce local haematoma

(ii) Subcutaneous (s.c.)
•The drug is deposited in the s.c tissue
which is richly supplied by nerves (irritant
drugs cannot be injected) but is less
vascular (absorption is slower than i.m).
•Self-injection (e.g. insulin) is possible b’se
deep penetration is not needed.
•The rate of absorption of drug is constant
and slow to provide a sustained effect.
•Sh’d be avoided in shock patients who are
vasoconstricted- absorption will be
delayed.
•The rate of absorption of drug is constant
and slow to provide a sustained effect.

(iii) Intravenous (i.v.)
•Drug is injected as a bolus or infused slowly
directly into a vein to produce rapid action.
•useful for certain irritant and hypertonic
solutions, as they are rapidly diluted by the
blood.
•Drugs in an oily vehicle or those which
precipitate blood constituents or
haemolyze erythrocytes should not be
given by this route.
•The dose of the drug required is smallest
(bioavailability is 100%)
•Thrombophlebitis of the injected vein and
necrosis of adjoining tissues if
extravasation occurs.

(iv) Intradermal
• The drug is injected into the skin raising a bleb.
• employed for vaccination e.g. BCG vaccine and for
testing the sensitivity e.g. penicillin injection.
(v) Intrathecal or Intraspinal
• For local and rapid effect of drugs on the meninges
or cerebrospinal axis, drugs are injected directly into
the spinal subarachnoid space.
• This is also used to produce spinal anaesthesia, or
for introduction of a radio-opaque contrast medium
into the subarachnoid space for visualizing the
spinal cord.
(vi) Intraperitoneal (i.p)
• This route is a common laboratory procedure, but it
is seldom employed clinically in infants for giving
fluids like glucose saline, as the peritoneum offers a
large surface for absorption.

INHALATION ROUTE
•The volatile liquids and gases are given by
inhalation route.
•The drugs may be given as solid particles, as
nebulized particles from solutions or in the form
of vapours.
•The volatile substances include gaseous
anaesthetics, amyl nitrite and vapours of liquid
anaesthetics, gases like oxygen, carbon dioxide
and helium.
•Nonvolatile substances have to be broken down
into small particles, and then inhaled as aerosols.
•Absorption takes place from the vast surface of
alveoli-action is very rapid.

•Rectal route
•Certain irritant and unpleasant drugs can be
put into rectum as suppositories or retention
enema for systemic effect.
•can also be used when the patient is having
recurrent vomiting or is unconscious.
•Inconvenient and embarrassing; absorption
is slower, irregular and often unpredictable
•Drug absorbed into external haemorrhoidal
veins (about 50%) bypasses liver
•Diazepam, indomethacin, ergotamine and
few other drugs are some times given
rectally.

Topical
•Refers to external application of the drug to the
surface for localized action.
•Drugs can be efficiently delivered to the
localized lesions on skin, oropharyngeal/ nasal
mucosa/ eyes, ear canal, anal canal or vagina in
the form of lotion, ointment, cream, powder,
paints, drops, spray, lozengens, suppositories or
pesseries.
•Other forms
•Nonabsorbable drugs given orally for action
on G.I. mucosa (sucralfate, vancomycin)
•inhalation of drugs for action on bronchi
(salbutamol, cromolyn sodium)
•irrigating solutions/jellys (povidone iodine,
lidocaine) applied to urethra

•Transdermal Absorption
•Absorption of drugs through intact skin is dependent on
SA over which they are applied & their lipid solubility
•The dermis is freely permeable to many solutes;
consequently, systemic absorption of drugs occurs readily
through inflamed, abraded, burned, or denuded skin
•Unwanted effects can be produced by absorption through
the skin of highly lipid- soluble substances (insecticide in
an organic solvent)
•Transdermal absorption can be enhanced by:
suspending the drug in an oily vehicle
Rubbing the resulting preparation into the skin
Hydration of the skin with an occlusive

Rights of medication administration
• Right patient. Know the patient to whom you are
administering the medication.
• Right drug. Know the correct medication to be
administered.
• Right dose. Know the correct dose to give the
patient.
• Right time. Know the correct time the medication
should be given, and inform the patient.
• Right route. Know the correct route of administration
by which the drug should be given.
• Right technique. Know the correct method
for administering the medication.
• Right documentation. Know how to complete a
patient’s chart accurately, with all pertinent
information.

DRUG DOSAGE FORMS
Dr.Peter Nuwagira, MSc,PhD fellow, MPS

LECTURE OBJECTIVES
• Define the term drug dosage forms
• Understand different drug dosage forms
• Give examples in each drug dosage forms
• Understand routes for different dosage forms
• Understand the four forms of drug dosages

Definition : This is a form in which a medicine/drug is prescribed for
use to the patient such as injections, tablets, capsules or syrups.
• Dosage forms do not contain just the active ingredient but also other
components called excipients or additives.
• These make the dosage form suitable for handling, administration and
enable it to release the active medicaments in the appropriate manner
to make it efficacious for treatment of diseases or conditions.
• Dosage forms can be in solid, semisolid, liquid or gaseous form.

Common dosage forms and their routes of administration
ROUTE OF
ADMINISTRATION
DOSAGE FORM
ORAL Tablets, Capsules, Solutions, Syrups, Elixirs, Suspensions,
Emulsions, gel powder, Granules
RECTAL Suppositories, ointments, creams and solution
TOPICAL Ointments, creams, pastes, lotions, gels, solutions, topical
aerosols(sprays)
PARENTERAL Injections(solutions,suspensions,emulsion)
LUNG Aerosols, inhalations sprays
NASAL Solutions, inhalations and gases
EYE/&EAR Solutions, ointments and creams

Description of common dosage forms.
1.TABLETS
Tablets are formulated as coated or uncoated.
Coated tablets include enteric coated, sugar coated, film coated and slow-release
coated tablets.
Enteric coated tablets
These tablets are covered with a special coating which resists break down in the
stomach but dissolves in the alkaline environment in the small intestines where the
drug is absorbed.The coating is intended to avoid irritating the stomach.

Slow-release tablets
• These are manufactured to provide a continuous, sustained release of certain drugs.
These tablet names are usually accompanied by abbreviations such as S.R or LA(long
acting) e.g Nifelat R
Sugar coated tablets
• These are formulated with a sugar coating to mask the bitter/sour taste of the active
ingredients.
Film coated tablets
• These tablets are covered with a thin layer of coating material.

Scored tablets
• These are tablets have an indented line running across the top of the tablet.
• Scored tablets are easily broken down into 2 pieces
Caplets
• These are easy to swallow coated tablets in forms of capsules eg panadol R

2. Capsules
• Capsules are cylindrically shaped solid unit dosage form containing one or more substance enclosed
within a hard or soft gelatin shell.
Types of capsules
Soft gelatin capsules: These capsules contain the drug in liquid form inside the shell eg.Vitamin A
capsule
Slow release capsules:
• These capsules contain pellets that dissolve in the GIT releasing the drug slowly thereby producing
sustained drug action e.g Olfen R
Hard gelatin/shell capsules
• These are manufactured in two pieces which fit together and hold the powder

3. CREAMS
• This is a semisolid emulsion of an oil and water (with the main ingredient being the
oil)
4. Lotions
• These are liquid or semi solid preparations containing one or more active ingredients
in a suitable vehicle.
• They are intended to applied to the unbroken skin without friction eg calamine lotion
5. Emulsions
• An emulsion is a suspension in which fat particles are mixed with water

6. Suppository
• It is a solid dosage form containing a solid base of glycerin or cocoa butter
intended for insertion into the body orifices where it melts, dissolves and
exerts a systemic or localized effect
7. Pessaries.
• These are solid preparations containing one or more active ingredients
intended to be inserted into the vagina eg Nystatin pessaries

7. Suspension
• This is a liquid preparation containing fine, undissolved particles of a drug suspended in it.
8.Aerosol
• This is a pressurized preparation that when activated releases a fine dispersion of liquid or
solid materials in a gaseous medium.
10. Enema
• A liquid intended to be injected into the rectum.
11. Inhalation
• Drug droplets, vapour, or gas administered by the oral or nasal respiratory route via an
aerosol or nebuliser.

12. Injection
• A sterile pyrogen-free preparation intended to be administered using a needle and syringe
(parenterally)
13. Lozenges(troches)
• Disk-shaped solid preparations intended to slowly dissolve in the oral cavity for localized
effects
14. Mouthwashes
• These are aqueous solutions containing one or more active ingredients.
• They are intended for use in contact with the mucus membrane of oral cavity.
15. Ointment.
• A semi solid preparation intended for external application to the the skin or mucous
membranes.

16. Pellet (implants)
• A sterile small, rod or ovoid-shaped mass intended to be implanted under the skin for
the purpose of providing the slow release of medication over an extended period of
time
17. Powder
• A mixture of finely divided drug particles or chemical substances.
18. Solutions
• A liquid preparation containing soluble chemical substances usually dissolved in water.
19. Spray
• A liquid minutely divided or nebulized as by a jet of air or stream

20. Syrup
• A concentrated sugar solution in water that may contain a sweetening agent or drug.
21. Eye drops
• These are sterile aqueous or oily solutions or suspensions of one or more active
ingredients intended for installation into the eye.

•Pharmacology differs from pharmacy,
•Pharmacy is a profession that is concerned with
the manufacture, preparation and dispensing of
drugs.
•Pharmacology is concerned with the effects of
drugs on living systems or their constituent
components such as cells, cell membranes,
cell organelles, enzymes and even DNA.
•Pharmacology uses physics, chemistry and
the biologic sciences to understand what
drugs do and how they do it.

Pharmacology with its various
subdivisions

Pharmacology Disciplines
1) Neuropharmacology: study of the effect of drugs
on components of the nervous system (brain,
spinal cord, nerves)
2) Cardiovascular Pharmacology: study of the
effects of drugs on heart, vasculature, kidney,
nervous and endocrine systems that participate in
cardiovascular function
3) Molecular Pharmacology: study of the
biochemical and biophysical characteristics of
interactions btn drug molecules and those of the
cell
4) Endocrine Pharmacology: study of drugs that are
hormones or hormone derivatives
5) Clinical Pharmacology: application of
pharmacodynamics and pharmacokinetics to
patients with disease

Pharmacology Disciplines cont’d
6) Chemotherapy: study of drugs used for
treatment of microbial/viral infection and
malignancies
7) Systems and Integrated Pharmacology:
study of
the use of whole animal approaches to best
predict the efficacy of new treatments in the
human
8) Veterinary Pharmacology: study of the use of
drugs for disease and health problems unique to
animals
9) Biochemical Pharmacology: study of how drugs
act with and influence the chemical ‘machinery’
of the organism

DRUG PROERTIES.pptx.....................

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