Drug
Drug may be defined as an
agent
or
substance,
intended for use in the
diagnosis,
mitigation,
treatment,
cure
or
prevention of disease in
human beings or animals.
Drugs
are
rarely
administered
in
their
original or crude forms.
They are administered in
different dosage forms by
converting
them
into
suitable formulations.
Dosage Forms
Dosage forms are the carrier through
which drug molecules are delivered to
sites of action within the body.
Every dosage forms is a combination of
the drug and different kinds of non – drug
components called as Excipients or
additives.
The additives are used to give a particular
Need For Dosage Forms
Accurate dose.
Protection e.g. coated tablets, sealed
ampules.
Protection from gastric juice, e.g. enteric
coated tablets.
Masking unpleasant taste and odour.
Provide drugs within body tissues, e.g.
injection
Sustained release medication.
Facilation of Insertion of drugs into body
Provide
optimum
drug
action
through inhalation therapy.
Provide drug action through topical
administration at local area of body.
e.g. creams, ointment, emulsion,
lotions etc.
Use of desired vehicle for insoluble
Classification
Solid dosage forms Unit dosage forms Tablets Capsule Powders Pills Bulk InternalFine powders & granules External Dusting powders Insufflations Dentifrice Snuffs Ear powders Liquid dosage forms Biphasic Emulsion Suspension Monophasic Internal External Syrups Elixirs Linctus Drops Liniments Lotions Gargles Throat paints Mouth washes Sprays Eye lotions Eye drops Nasal drops
Solid dosage forms
Tablets Pills
Dusting Powders
Capsules
Solid dosage forms one of the oldest dosage forms and
most of the solid dosage forms are available in Unit dose.
Unit dose may be defined as a exact quantity of the drug
administered at once. e.g. Tablets, Capsule, pills, cachets, powders etc.
When drugs are to be administered orally in dry state, then
tablets, capsules are most convenient dosage forms.
Some solids are supplied in bulk (Means quantity available
Dusting Powders
Dusting powders are applied externally to skin, so
they should be applied in very fine state to avoid local irritation. Hence dusting powders should be passed through sieve no 80 to obtained fined powders.
Dusting powders are prepared by mixing of more
than one ingredients in which either starch, kaolin, or talc are used in their formulation. Generally talc or kaolin are used because they are inert in nature.
Dusting powders are used for antiseptic, astringent,
absorbent, antiperspirant etc.
Dusting powders are of two sub type they are as
Medical Dusting
Powders
Medical Dusting powders are used to
increase superficial condition of skin.
These are not applied on wounds, burns
etc
Medical dusting powders must be free
Surgical Dusting Powders
Surgical dusting powders are used in
body cavities and also on major wounds
like as burns etc.
They should be sterilized before use.
They are mainly used for their antiseptic,
Insufflations
These are medicated dusting powders meant
for introduction into body cavities (nose, throat,
ear, vagina etc) with the help of an apparatus
known as a insufflator.
It sprays the powders (in a state of fine
particles) on site of application.
Now a days insufflations are also available in
pressure aerosols. This pressure aerosols are
used for administration of potent drug.
They are used in the treatment of ear, nose,
Snuffs
These are finely divided solid dosage
forms of medicaments which are inhaled
into nostrils.
They are mainly used for their antiseptic,
Granules
Granulation is the process in which
primary powder particles are made to
adhere to form larger multiparticle or
large particles entities called granules.
The bitter, nauseous, unpleasant powders
can not be given tablets, capsule due to bulk quantity are required to be taken, as well as they are not given in liquid dosage forms due to their stability such powders are given in the granules forms.
These powders are mixed with suitable
exicipent along with granulating agent,
prepare a coherent mass then dried & passed through the sieve to obtained desired size of granules.
Effervescent Granules
Effervescent granules are
meant for internal use.
They contained medicaments
mixed with citric
acid, tartaric acid & sodium bi carbonates
,
sometime saccharin or sucrose may be added for
sweetening taste.
Before, administration desired quantity of
granules
are dissolved in water, the acid & bicarbonate
reacts with each other to produce effervescence.
Effervescent granules are prepared by two
Heat method
A large porcelain or stainless steel evaporating dish is placed
over the boiling water bath.
The dish must be sufficiently hot (generally heating takes
place for 1 – 5 min.) before transferring the powders into it, to ensure rapid liberation of water of crystallization from citric acid.
If heating of the dish is delayed then the powder which is
added to it, will heat up slowly & liberated water of crystallization will also be liberated simultaneously.
As a result, sufficient water will not be available to make a
coherent mass.
This coherent mass will pass through the sieve to obtained
suitable size of granules, dry it in oven at 600c then packed in
Wet method
In this methods all the ingredients are mixed
thoroughly
This powders mixture make moistened with non –
aqueous vehicle (e.g. alcohol), to prepare a
coherent mass which is then passed through
sieve no 8 to obtained suitable granules.
Then dried in oven at 60
0c. The dried granules
are again passed through the sieve to break the
lumps which may be formed during drying.
The dried granules are packed in air tight
Tablets
These are solid dosage forms of medicaments
which are prepared by moulding or by
compression with or without Excipients.
The tablets can be prepared by two methods
namely as a
Capsule
Capsules are solid unit dosage forms in which one or
more medicaments enclosed within a shell.
Capsules mainly divided in to two parts namely as –
I)
Body
(Longest part of capsule shell), II)
Cap
(Smallest part of capsule shell)
The capsule are generally prepared by gelatin.
Depending on their formulation, two types of gelatin
are used namely as – I)
Hard gelatin
, II)
Soft gelatin
.
Pills
These are small, rounded solid dosage forms
containing medicaments intended for oral use.
The medicaments are mixed with excipients to forms
a firms plastic mass.
The mass is rolled to uniform pill pipe, which cut into
numbers of uniform pills. The pills are spherical in
shape & produced by rolling them under wooden pill
rounder.
Sometimes pills are coated with varnish, gold leaf, etc
to improve finish, unpleasant taste & stability.
Disintegration time of pill is uncertain means freshly prepared
pills are disintegrates readily rather than old dried pills.
It is difficult to prepare pills of uniform size & weight.
It may be defined as “A solution is a
liquid-preparation that contains one or more soluble
chemical substances dissolved in a specified solvent”
Liquid dosage forms are intended for External,
Internal or parenteral use.
The component of the solution which is present in a
large quantity is known as
“SOLVENT”
where as the
component present in small quantity is termed as
“SOLUTE”
They mainly classified in to two category namely as –
I)
Monophasic Liquid dosage forms.
Advantag
e
Immediately available for absorption.
Administration convenient, particularly for infants,
psychotic patients.
Easy to color, flavor & sweeten.
Liquids are easier to swallow than solids and are
therefore particularly acceptable for pediatric patient.
A solution is an homogeneous system and therefore
the drug will be uniformly distributed throughout the
preparation.
Disadvantag
e
Less stable in aqueous system. Incompatibility is faster in
solution than solid dosage form.
Patients have no accurate measuring device.
Accident breakage of container results in complete loss.
Solution often provide suitable media for the growth of micro
organisms.
The taste of a drug, which is often unpleasant, is always more
pronounced when in solution than in a solid form.
Monophasic liquid dosage forms are represent by true or
colloidal solution.
The component of the solution which is present in a large
quantity is known as “SOLVENT” where as the component present in small quantity is termed as “SOLUTE”.
A solution is homogenous because the solute is an ionic or
molecular forms of subdivision.
In case of colloidal solutions, the solutes are present as
aggregates although they cannot be seen by necked eye or ordinary microscope.
It is sub classified as –
Monophasic Liquid Dosage forms
Internal Use External Use
Syrup Elixirs Linctuses Drops
Liniments Lotions Gargles
Mouth Wash Throat paints sprays
Syru
p
It is a concentrated or saturated solutions of
sucrose in purified water.
The concentration of sucrose is
66.7%
w/w
& due
to that it is a viscous preparations.
The syrup which contains medical substance
called as a
medicated syrup
& those containing
aromatic or flavored substance known as a
Importance of syrup
It retards oxidation because its partly hydrolyzed
into reducing sugar.
It prevents decomposition of many vegetable
substance because its have high osmotic
pressure which prevent the growth of bacteria.
It is clear, sweetened,
aromatic,
hydroalcholic
preparations meant for oral
use.
The medicated elixirs are
generally contained potent
drug
like
as
antibiotics,
antihistamine or sedative ,
where as non – medicated
elixirs contained flavoured.
The composition of elixirs
contained mainly as ethyl
alcohol
(active
ingredients),water, glycerin or
propylene glycol, colouring
agent, flavouring agent &
preservative.
Linctus
es
These are viscous liquid preparations
that’s are used for the treatment of cough.
They contain medicaments which have
demulcent, sedative, expectorant action.
They are taken in small doses without
diluting with water to have prolonged effect of medicines.
Simple syrup is used as a vehicle for
most of the linctuses.
Tolu syrup is preferred in certain cases
Dro
ps
These are liquid preparations meant for oral
administration.
The oil soluble vitamins, such as vitamin A & D
concentrates in fish – liver oil are presented as drops
for administration.
Since these preparations contain potent medicaments,
the dose must be measured accurately
The following two methods are commonly used for this
purpose.
Use of a dropper which is accurately graduated in
fractions of a milliliters.
Liniments
Liniments are liquid or semi- liquid
preparations meant for external application to the skin.
They are usually applied to the skin with
friction & rubbing of the skin.
Are usually alcoholic and oily liquid
preparations (monophasic) or emulsion (biphasic).
Alcoholic liniments are used generally for their
rubefacient and counterirritant effects. Such liniments penetrate the skin more readily than do those with an oil base.
The oily liniments are milder in their action
and may function solely as protective coatings
Liniments should not be applied to skin that
Lotions
Are usually aqueous, alcoholic
or oily liquid preparations.
They are intended for external
application without friction or
rubbing to the affected area
Usually applied with the help of
some absorbent material such
as cotton wool or gauze.
It is generally used to provide
Gargles
Gargles are aqueous solutions used for treating throat
infection (pharynx and nasopharynx part)
Supplied in concentrated forms with directions of dilution with
warm water before use
They are used into intimate contact with the mucous
membrane of throat for few seconds, before they are thrown out of the mouth.
They are used to relieve soreness in mild throat infection.
They are also used for their antiseptics, antibiotics and/or
Mouth wash
These are aqueous solutions
with pleasant or acceptable
taste & odour
These are used to make clean &
deodorise the buccal cavity or
used for oral hygiene and to
treat infections of the mouth.
They
mainly
contain
Throat paints
Throat paints are viscous
liquid preparations used for
mouth and throat infections
Glycerin is commonly used
as a base because being
viscous it adheres to
mucous membrane for long
period and it possess a
Sprays
These are the preparations of drugs in
media which may be aqueous, alcoholic, or glycerin.
They are applied to the mucous
membrane of throat or nose with an atomizer.
The throat sprays must be sprayed from a
special type of atomizer known as a nebulizer, which removes the large droplets by baffling system. Only precaution should be taken that the fine droplet will used to easily reach the lungs.
Inhalations
These are liquid preparations containing volatile substance &
are used to relieve decongestion & inflammations of respiratory tract.
The volatile substance in inhalations would be volatile at room
temperature so that they should be placed on some adsorbent pad or handkerchief.
In some cases inhalations will added to hot water (650c) then
Nasal drops
Drugs in solution may be instilled into the nose from a dropper
or from a plastic squeeze bottle.
The drug may have a local effect, e.g. antihistamine,
decongestant.
Alternatively the drug may be absorbed through the nasal
mucosa to exert a systemic effect.
The use of oily nasal drops should be avoided because of
possible damage to the cilia of the nasal mucosa & if it is used for long period may reach the lungs & cause lipoid pneumonia.
To avoid that Nasal drops are prepared so that they are similar
Eye drops
Sterile, aqueous/oily solutions or suspensions intended for
instillation in eye sac.
Eye drops may contain buffers, stabilizing agents,
dispersing agents, solubilising agents, anti-oxidants & agents required for tonicity/ viscosity adjustment
Single dose container should not contain anti-microbial
preservative.
In case of multi dose container a dropper should be
Eye lotions
These are the aqueous solutions used for washing the eyes. These are supplied in concentrated forms & are required to
diluted with warm water immediately before use.
They should be free from foreign particles to avoids irritation
to the eye.
They are required to prepared fresh & should not be stored
Ear drops
These are the solutions of drugs that are instilled into ear
cavity with the help of dropper.
These are generally used for cleaning the ear, softening
the wax & for treating the mild infections.
The solutions is generally prepared in water, glycerin,
Biphasic liquid dosage
forms
The liquid which consist of two phases are known as a
biphasic liquid dosage forms.
They are sub categorized into two different forms namely
as –
I) Emulsion II) Suspension
In emulsion both phases are available in liquid where as in
Emulsion
Emulsion is a biphasic liquid preparations containing two immiscible
liquid (Continuous Phase & dispersed phase) made missicible.
The liquid which is converted into minute globules is called as
dispersed phase & the liquid in which the globules are dispersed is called the continuous phase
dispersed phase
continuous phase
Two Immiscible Liquids
Dispersed Phase
(Internal phase)
Continuous Phase
(External phase)
An emulsion is a thermodynamically unstable system
consisting of at least two immiscible liquid phases one of which is dispersed as globules in the other liquid phase stabilized by a third substance called emulsifying agent.
Examples for emulsions:- milk, rubber latex, crude oil etc.
A.: Two immiscible liquids not emulsified
B. An emulsion of phase B dispersed in Phase A
C. Unstable emulsion slowly separates.
Types of emulsions
Simple type
Water in oil (w/o)
Oil in water (o/w)
Depending on globule size
Micro emulsion
Fine emulsion
Special type
Water in oil (w/o)
In this types of emulsion water is dispersed phase & oil is
continuous phase
w/o types of emulsion generally meant for External use. Examples are butter, lotions, creams etc.
In rare case they are used internally.
Water is dispersed phase
Oil in water (o/w)
In this types of emulsion oil is dispersed phase & water is
continuous phase
o/w types of emulsion meant for both Internal use &
External use.
Examples for internal use are Vitamin A in corn oil, liquid
paraffin in water etc.
Examples for External use are Benzyl benzonate emulsion.
Oil is dispersed phase
Micro Emulsion
These are clear dispersions of o/w or w/o in which the globules have
small size like as a 10nm or 0.01 µm..
Being cleared products micro emulsion are more popular now a days.
Micro emulsions are thermodynamically stable optically transparent ,
Fine emulsion
Normally these have a milky appearance.
Multiple emulsion
These are emulsion with in emulsion & designated as w/o/w
or o/w/o.
The drugs that is incorporated in the innermost phase must
cross two phase boundaries before getting absorbed.
It is generally used in oral sustained release or
Identification tests
Dilution test
Conductivity test
Dye test
Fluorescence test
Dilution test
The emulsion is diluted with water, after dilution emulsion
remain stable then it is said to be o/w type of emulsion because water is in continuous phase. If emulsion is break after dilution with water then it is said to be w/o type of emulsion.
Add drops of water
Water distribute Uniformly
Add drops of water
Conductivity test
Conductivity test can be performed by dipping a pair of electrode
connecting with low voltage bulb & pass the current.
If bulb glows then it is said to be o/w type of emulsion because
water is in continuous phase & it is good conductor of electricity.
If bulb doesn't glow then it is said to be w/o type of emulsion
because oil is bad conductor f electricity.
Bulb glows with O/W
Emulsion Emulsion
Dye test
Oil soluble Scarlet red dye is mixed with emulsion.
Place a drop of emulsion on microscopic slide cover it with
cover slip & examine under microscope.
If disperse globules appears red & ground is colourless
then it said to be o/w type of emulsion because water is present in continuous phase.
If reserve condition occurs (If disperse globules appears
colourless & ground is red colour then it said to be w/o type of emulsion because oil is present in continuous phase.)
Oil is dispersed phase
Water is continuous
phase
Water is disperse phase
Fluorescence test
Certain fixed oil posses the physical properties of
fluorescing in the presence of ultraviolet radiations.
If examine under microscope ground is fluorescence then it
said to be w/o type of emulsion because oil is present in continuous phase.
If examine under microscope droplet is fluorescence then it
Creaming test
The direction of creaming identifies the emulsion type, if
the densities of aqueous and oil phases are known.
Water-in-oil emulsions normally cream downward as oil
is usually less dense than water.
Cobalt chloride test
Pour the emulsion on filter paper then it is soaked in cobalt
chloride solutions & allowed to dry turns from blue to pink.
Then this emulsion is said to be o/w type of emulsion.
This test may fail if emulsion unstable or breaks in
Filter paper test
This test is based on the fact that an o/w emulsion will
spread out rapidly when dropped onto filter paper.
In contrast, a w/o emulsion will migrate only slowly. This
Suspension
Suspensions are the biphasic liquid dosage
forms of medicament in which finely divided solid particles ranging from 0.5 to 5 micron are dispersed in a liquid or semisolid vehicle, with aid of single or combination of suspending agent.
In which solid particles acts as disperse
phase where as liquid vehicle acts as continuous phase
The external phase (suspending medium) is
generally aqueous in some instance, may be an organic or oily liquid for non oral use.
The particle size for non oral suspension is
Advantage of suspension
Suspension can improve chemical stability of certain drug.
E.g. Procaine penicillin
Drug in suspension exhibits higher rate of bioavailability
than other dosage forms.
Solution > Suspension > Capsule > Compressed Tablet > Coated tablet
Duration and onset of action can be controlled. E.g.
Protamine Zinc-Insulin suspension.
Suspension can mask the unpleasant/ bitter taste of drug.
Disadvantage of suspension
Physical stability , sedimentation and compaction can
causes problems.
It is difficult to formulate.
Uniform and accurate dose can not be achieved unless
suspension are packed in unit dosage form.
All suspensions are required to be shaken before
measuring of dose.
The storage of suspension may lead to changes in
Ideal qualities of good
suspensio
n
It should settle slowly & easily re – dispersed on shaking It should readily & evenly pour from container.
It should be chemically inert. It should not forms hard cake.
It should prevent degradation of drug or to improve
stability of drug.
Flocculated suspension
In this type, solid particles are loosely aggregates themselves, means
individual particles are come in contact with each other to forms network like structure called as a floccules.
These flocs are light, fluffy in nature, which are held together by weak
van der waals force of attraction.
Aggregation is achieved by adding flocculating agent. This suspension will readily sediments.
This suspension posses better physical stability but less bioavailability
Deflocculated suspension
In this type of suspension, individual particle exits as a separate entity,
means particles carry a finite charges on their surface . Hence particles approaches each other, they experience repulsive forces. This force
create a high potential barrier, which prevents a aggregation of
particles.
During storage, these suspension shows a sedimentation at slow rate,
due to that particles forms a close packing arrangement.
So that it is difficult to re dispersed on agitation & forms a cake or
claying which is hard in nature.
This type of suspension have shorter shelf life but high bioavailability as
Difference between flocculated & deflocculated
suspension
Flocculated Suspension Deflocculated suspension
Particles form loose aggregates & forms network like structure.
Particle exist as separate entities.
Particles experience attractive forces.
Particles experience repulsive forces.
Supernatant liquid is clear. Supernatant liquid is cloudy.
The rate of sediment is high. The rate of sediment is slow.
Sediment is rapidly formed. Sediment is slowly formed.
sediment are loosely packed, hence hard cake is not formed.
Sediments are closely packed, hence hard cake is formed.
The sediment is easy to redisperse on shaking.
Sediment is difficult to
redisperse on shaking. (due to formation of hard cake)
Bioavailability is comparatively less.
Bioavailability is relatively high.
The suspension is not pleasing in appearance.
Semisolid dosage forms meant for external application Semisolid dosage forms subcategorized are
I) ointment
II) creams
III) paste
IV) Jellies
V) Suppositories
The suppositories are also included in this category but it is
a unit dosage forms.
Ointment
Ointment are semisolid preparation meant for application to
skin or mucous membrane.
The ointments are mainly used for their protective or emollient
properties
It may be defined as a medicament or medicaments dissolved,
suspended or emulsified in ointment base.
There is no single ointment base which possesses all the
Qualities of ideal ointment
base
It should be inert, odourless & colourless & smooth. It should be physically & chemically stable.
It should be compatible with the skin & with incorporated
medicaments.
It should be of such consistency that it spread & soften
when applied to skin with stress.
It should not retard healing of wound.
Classification of ointment
base
Oleaginous bases Absorption bases Emulsion bases
Oleaginous base
These bases consist of water soluble hydrocarbons,
vegetable oils, animal fats & wax.
The constituents of hydrocarbon bases are soft paraffin,
hard paraffin & liquid paraffin.
The vegetable oils are mainly used in ointment to lower the
melting point or to soften the bases.
These bases serve to keep the medicaments in prolonged
contact with the skin & also act as occlusive dressings. They have a low capacity to absorb water & are used chiefly for their emollient effect.
These bases losing their importance now a days for the
Disadvantages of oleaginous
bases
They are greasy.
They are sticky & are difficult to remove both from skin &
clothing.
They retain body heat which may produce an
uncomfortable feeling of warmth.
Absorption bases
These bases are generally anhydrous substance which
have the property of absorbing considerable quantities of water but still retaining their ointment like consistency.
The absorption bases are of two type namely as
I) Non emulsified bases
II) Water in oil emulsion
Non emulsified bases absorb water & aqueous solutions
producing w/o emulsion. E.g. Wool fat, wool alcohol, beeswax & cholesterol.
Water in oil emulsions are capable of absorbing more water
Emulsion bases
These bases are semisolid or have cream like consistency.
Both o/w or w/o emulsions are used as a ointment base.
The o/w emulsion base is more popular now days because
ease of application will easily achieved.
The w/o type of emulsion bases are greasy & sticky.
The emulsifying ointment is prepared from emulsifying
Water soluble bases
These are commonly known as greaseless ointment bases.
The water soluble bases consist of water soluble ingredients such
as carbowaxes ( polyethylene glycol polymer)
The carbowaxes are water soluble, non – volatile & inert
substance.
Selection of appropriate carbowaxes is depend on their molecular
creams
These are viscous semisolid emulsions which are meant for
external use.
Cream is divided in to two types namely as
I) Aqueous creams II) Oily creams
In case of aqueous creams the emulsions are o/w type & it is
relatively non greasy. The emulsifying waxes are anionic, cationic & non –ionic used. Generally polysorbate,
triethanolamine soap are used as emulsifying agent.
In case of oily creams w/o type & it is relatively greasy. The
emulsifying agent such as wool fat, wool alcohols, beeswax & calcium soap is used.
The cream should be store in collapsible tube & supplied in well
pastes
Pastes are semisolid preparations
intended for external application to skin.
The pastes are generally very thick & stiff.
They do not melt at ordinary temperature
& thus forms a protective coating over the area where they are applied.
Pastes are differ from ointment as they
contain a high proportion of finely powdered medicaments.
They are mainly used as a antiseptic,
protective, soothing dressings.
Pastes should be stored & supplied in
jellies
Jellies are transparent or translucent, non greasy, semi solid
preparations mainly used for external application to skin.
These are also used for lubricating catheters, surgical gloves
& rectal thermometer.
The substance like gelatin, starch, tragacanth, sodium
alginate & cellulose derivatives are used for the formulation of jellies.
Jellies are of three types namely as
Introductio
n
With the advancement of pharmaceutical sciences, a new concept have evolved various modern dosage forms & methods of their administration. Some of the modern dosage forms are
Implants
Films & strips
Liposome drug carriers
Controlled drug delivery modules Erythrocytes
Implants
These are hypodermic tablets are placed under the skin by a minor
surgery in order to release drugs over prolonged periods of time.
Now the magnetically controlled implants have been developed which
can be opened or closed at will in order to release or stop the drug.
These implants are placed at upper thigh at a depth of 5mm.
Films & strips
These are meant for topical application for slow release of drug over predetermined period of time. Films & strips are more popular these days. They are sub categorized in to following types namely as
Zero order release films Buccal strips
Zero order release films
These are called as laminates & meant for topical application.
E.g.
Nitroglycerine laminates are prepared by mixing propylene glycol
Buccal strips
The buccal & sublingual tablets are now replaced with
buccal strips.
These strips consist of a thin absorbent base of fabrics,
filter paper & cotton etc.
The buccal strips are prepared by immersing a long piece
of fabric made from polyamide fibers into a molten mixture of carbowaxes & dissolved or dispersed the drug.
The fabric is then cooled & cut into small pieces.
It should be contact with buccal mucosa for about 15 min.
Spray bandage
These bandage are prepared by spraying the solution of drug in
polylactide (polymer of lactic acid anhydride)
A solution of purified lactide polymer is made in chloroform.
It is then packed in aerosol container having suitable propellant. When these solution sprayed then it will be a comfortable
Liposome drug carriers
These are several carriers in our body which transport both
to an other like as enzymes, proteins etc.
These are phospholipids which can transport both
hydrophilic & hydrophobic drugs.
The large multilamellar vesicles (LMV), small unilamellar
Applications
Used in diseases caused by intracellular parasites. E.g.
malaria, tuberculosis & amoebiasis.
It entrapped insulin is active orally & can be replaced by IM
administration of insulin.
It can be used to transport functional DNA/RNA molecules
into cell.
It can be used to transport radio pharmaceuticals &
immunological products.
Liposomal daunomycin has longer duration of action than
Controlled drug delivery
modules
These are the device which are formed by embedding the
drug within a polymeric matrix so that it gets released slowly to the body over a long period of time.
It will formed drug – polymer complex & may be formulated
in to tablet, capsule or any other suitable formulation.
These modules are punctured before administration with
leaser beam to make a small orifice for release of the drugs.
The drugs is released from these modules by diffusion,
osmosis or chemical reactions.
These are applied to skin, implanted subcutaneously or
Erythrocytes
Erythrocytes are tried in order to achieve controlled release
of drugs.
The life span of erythrocytes are 120 days.
It can allow a drug to circulate in the body for long period of
time which help slow release of the drugs in to serum.
Released erythrocytes are prepared by putting them in to a
hypotonic medium. So that they can easily swollen.
The aqueous solutions of the drug is added to the medium
so that drugs gets in to erythrocytes through open pores.
When isotonicity is adjusted the erythrocytes shrink, thus
Applications
Released erythrocytes of urease have been used in kidney
failure to degrade serum urea.
Released erythrocytes of asparaginase have shown good
result in asparaginase dependent leukemia.
Released erythrocytes of methotrexate & adrianycin have
been tried in cancer therapy.
Released erythrocytes of prednisolone have shown good
Nanoparticles
It is based on colloidal drug delivery system.
The particles size of this system is in nanometer range (200 – 500 mm) The system consist of a drug & carriers to deposit the drug at target
site.
The carriers used are naturally occurring macromolecules like human
Applications
Flourescein isothinocyanate (FITC) nanoparticles have been
used to incorporate cytotoxic agent into tumor cell in cancer chemotherapy.
Nanoparticles along with biological maker like immunoglobulin
Prodrugs
The compound which undergo biotransformation before showing
desired pharmacological activity are called prodrugs or proagents.
Prodrugs are generally the ester or amides of parent drugs. These are useful to improving the stability, solubility,
Applications
Choramphenicol palmitate, the prodrug of chloramphenicol is used
in the preparation of pediatrics suspension because it has no bitter taste.
Procaine penicillin G & benzathine penicillin G are prodrugs of
penicillin G which shows resistance to hydrolysis as compared to the parent drug.
Cindamycin 2- phosphate the prodrug of cindamycin has no bitter
