Transcript general_pharmacology

GENERAL PHARMACOLOGY
Prepared by
Prof. Abdulkader.H.El Daibani
General pharmacology
Pharmacology
is the science of drugs and deals with
pharmacokinetics and
pharmacodynamics of drugs.
General pharmacology
Pharmacokinetics:
Affects of cellular components on drugs
and include: absorption, distribution
,metabolism (Bioavailability) and excretion
(ADME) of drugs and also deals with
pharmacokinetics parameter and
mathematical relationship.
Pharmacodynamics:
Deals with the affects of drugs on cellular
components and include: mechanism of
action e.g. interaction with receptors,
response ,side effects ,adverse effects and
toxicity.
General pharmacology
A drug:
is any substance which alters body
functions and used in prophylaxis , or
diagnosis or treatment of disease.
Drug nomenclature:
Chemical name: Acetyl salicylic acid.
Generic name: Aspirin.
Trade name: Aspro,Dispril.
General pharmacology
Source of drugs:
 Plants: Atropine,digoxin, ephedrine ,morphine
,reserpine.
 Mineral: Iron, calcium.
 Animal: insulin
 Microorganism: penicillin, streptomycin
 Synthetic: aspirin, sulfonamide.
 Semisynthetic: Ampicillin
 Genetic engineering: using recombinant DNAtechnology e.g. humman insulin, Erythropoietin
,growth hormone
Dosage forms of drugs
A dosage form of a drug is the form in
which the drug is administered to the
patient.
It may be classified according to the
route of administration.
Dosage forms of drugs
I) Dosage forms given orally:
A) Lipid preparation
These are solutions of drugs in either
aqueous or alcoholic vehicles as the
following:
Aqueous preparation
Aromatic water, Syrups, Emulsion and
Infusion.
Alcoholic preparation
Elixirs, Spirits (Essences) and Tinctures
Dosage forms of drugs
1) aqueous preparation:
Aromatic water (Aqua):
They are saturated aqueous solutions of volatile oils
or substances in distilled water e.g. aqua peppermint
or peppermint water. They are mainly used as
vehicle for dissolving water soluble substances in
order to improve their aroma and flavor.
Syrups:
they are concentrated aqueous solutions of sugar
containing flavoring, coloring or therapeutically
active substances. Also they are used as vehicles for
water soluble drugs and cough mixtures.
Dosage forms of drugs
Suspensions:
it mixture of small water insoluble solid
drug particles dispersed in water using
suspending agent e.g. gums.
Emulsion:
it is a milky solution with better taste and
odour. It is intimate mixture of two
immiscible liquids using third substance
(emulsifying agent) e.g. oils suspended in
water by gums acacia, which increases the
viscosity of the medium (cod liver oil
emulsion).
Dosage forms of drugs
2)Alcoholic preparation:
Elixirs:
These are sweetened and flavored
hydroalcoholic solutions that contain
varying amounts of alcohol. Elixirs may be
either non-medicated to be use only as
vehicle (e.g. bitter orange elixir) or
medicated, when they include specific
drugs (e.g. barbital elixir).
Dosage forms of drugs
Spirits (Essences):
 They are volatile oils dissolved in
alcohol e.g. spirit of aromatic
ammonia, peppermint spirit, and
lemon spirit.
Dosage forms of drugs
Spirits (Essences):
they are volatile oils dissolved in alcohol
e.g. spirit of aromatic ammonia,
peppermint spirit, and lemon spirit.
Tincture:
they are alcoholic solutions of non-volatile
substances (vegetables). The concentration
of drug may up to 10% in case of potent
drug e.g. belladonna, and up to 20% in
non- potent drug.
Dosage forms of drugs
B) Solid preparations:
They are include tablets, capsules,
powders, and sustained release tablet
or capsules.
Dosage forms of drugs
Tablets:
 They are prepared by compressing the drug in
granular form.
 Tablets may be coated with gelatin , sugar, and
chocolate.
 If they produce gastric irritation, they can be enteric
coated.
Enteric coated tablets:
 These are tablets coated with substances, which resist
dissolution in the acid juice of the stomach but it
dissolve in alkaline juice of intestine.
Dosage forms of drugs
Capsules :
 They are shells (containers) of gelatin used
for containing individual doses of drugs.
they provide accurate medication of drugs
in a tasteless form.
Capsules may be:
 Hard capsules contain powder drugs.
 Soft or flexible capsules contain liquid.
 Enteric capsules dissolve only in intestine.
Dosage forms of drugs
Powders:
Powder form of drugs may be dispensed in small
paper packets or in bulk. It may be formulated in the
form of effervescent granules when they mixed with
sodium bicarbonate and citric acid e.g. K citrate,Mg
sulphate.
Sustained release (time release) tablet or capsules:
These are long acting oral preparations. They are
formed of groups of drug particles each is coated with
special envelope that dissolve at different dissolution
rates to give a long acting effect e.g. antihistamines.
Dosage forms of drugs
II)DOSAGE FORMS GIVEN RECTALLY OR VAGINALLY:
 Drugs may be given rectally in one of the following dosage
forms
Suppositories:




They are solid preparations intended for insertion into the
rectum.
They contain the drug in waxy or fatty medium that
liquefies or librates the drug after insertion into the rectum
or the vagina.
They melt at body temperature. Allowing the ingredients to
be released and exert their medicinal action.
Suppositories are also available for insertion into the vagina
(celled pessaries, ovules or tablets) or urethra (bougies).
Dosage forms of drugs
Enema:
It can be applied into the rectum
either for therapeutic purpose to
evacuate faeces (evacuation or
cleansing) and to introduce drugs for
absorption by rectal mucosa
(retention enema) or for diagnosis
purpose by using barium dye with Xray in lower gastrointestinal tract
(called barium enema).
Dosage forms of drugs
III) DOSAGE FORMS GIVEN PARENTALLY:
 Preparation or solution for injection should be sterile,
triple distilled and pyrogen free (pyrogen: are
bacterial products which cause a rise in body and
rigors when injected).
 The glass container should be neutral as not react
with drug.
 The contents are usually liquid but may be in powder
form to dissolve immediately before use.
 They may be dispensed in (ampulse) containing single
doses of drugs, or vials which are rubber capped
bottles containing a number of doses.
Dosage forms of drugs
IV) Preparation for respiratory passages:
 Drug may be introduce though the respiratory in one
of the following forms:
 Gases: Oxygen and cyclopropane ( a general
anesthesia) can be administered through especial
devices.
Vapours: volatile liquids. e.g. diethyl ether ( as general
anesthesia) and amyl nitrite (as coronary vasodilator)
inhaled to produce their desired effect.
Steam inhalation:
 The drug may be vaporized by means of staem and
then inhaled e.g. benzoion inhalation.
Dosage forms of drugs
Aerosols:
 the drug is released into the respiratory
passages in the form of a fine mist of liquid
droplets. Depending on the size of the
droplets the drug may remain in the upper
tract or travel down to the pulmonary
system.
 The drug e.g. disodium cromoglycate
(Intal), may also available a finely divided
micronized particles in capsules. The
capsules are punctured by special inhaling
device, e.g.Spinhaler and the fine particles
are inspired.
Dosage forms of drugs
V) PREPARATION INTENDED FOR EXTERNAL USE
(TOPICAL APPLICATION):
 They are applied on the surface of skin or mucous
membrane.
Ointments:
 These are semisolid preparations that may be applied
to the skin or mucous membranes. The ointment base
incorporates the drug which is usually intended to act
locally. Some ointment bases, however, allow for
some drug absorption to take place.
Dosage forms of drugs
Liniments:
 these are preparation of various substances
in an oily, soapy or alcoholic vehicle in
tended to be applied to the skin by rubbing.
Liniments are usually used for their
counter-irritant effects, e.g. camphor
liniment.
Lotion:
 these are aqueous suspensions intended
for application to the skin without rubbing
e.g. calamine lotion, and benzyl benzoate
lotion.
Dosage forms of drugs
Lozenges:
 These are table-like formulation that are
intended for slow dissolution in the mouth.
They are used principally for continuous
application of drugs to the mucous
membrane of the mouth and throat.
Mouth washed and gargle:
 These dosage forms are used foe local
action of drugs on the mucous membrane
of the mouth (called mouth wash) and
throat (called gargle).
Dosage forms of drugs
Ophthalmic solution:
 these are aqueous solutions of the
drugs to be used in the eye either in
the form of drops eye drops) or as
wash (lotion).
Ear and nose drop:
 Used to produce a local effect in the
ear or nose.
Dosage forms of drugs
Powder:
 Some powders are applied to skin for
protective purposes mainly, and are termed
dusting powder, e.g. talcum powder.
Vaginal douches:
 These are aqueous solutions, which usually
have cleansing or antiseptic properties.
They are available as powders or tablets to
be dissolved in a given amount of warm
water.