osmotic drug delivery system , principle of osmosis , classification, advantages, disadvantages, applications and basic components of ODDS.

1. SCHOOL OF PHARMACEUTICAL SCIENCES, MOHAN BABU UNIVERSITY
TITLE : OSMOTIC ACTIVATED DRUG DELIVERY SYSTEMS
SUBJECT : DRUG DELIVERY SYSTEMS
ACADEMIC YEAR : 2023-2024
Presented by :
N. Thanuja
M pharmacy – 1st year
Department of pharmaceutics
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2. LIST OF CONTENTS
INTRODUCTION
PRINCIPLE OF
OSMOSIS
BASIC
COMPONENTS
OF ODDS
CLASSIFICATION
OF OSMOTIC
PUMP
ADVANTAGES
DIS
ADVANTAGES
APPLICATIONS
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3. Introduction
Osmotic pressure is used as the
driving force for osmotic to
release the drug in a controlled
manner.
Osmotic controlled drug
delivery system generally
consist of a core including the
drug an osmotic
agent, excipients and
semipermeable membrane
coat.
Osmotic pressure gives zero
order drug delivery which
is driven force for release of
drug from dosage form.
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4. PRINCIPLE OF OSMOSIS
 Osmosis refers to the process of movement of solvent from lower
concentration of solute towards higher concentration of solute across a
semipermeable membrane.
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5. Continuation ;
 Abbe Nollet first reported osmotic effect in 1748, but Pfeffer in 1877 had the
pioneer of quantitative measurement of osmotic effect.
 Pfeffer measured the effect by utilizing a membrane which is selectively
permeable to water but impermeable to sugar. The membrane separated
sugar solution from pure water. Pfeffer observed flow of water into the sugar
solution that was halted when a pressure p was applied to the sugar solution
Pfeffer postulated that this pressure, the osmotic pressure π of the sugar solution
is proportional to the solution concentration and absolute temperature.
 Van't Hoff established the analogy between the Pfeffer results and the ideal gas
laws by the expression.
 Where, n2 represent the molar concentration of sugar or other solute in the
solution, R represent the gas constant and T represent the absolute
temperature.
 Another method of obtaining a good approximation of osmotic pressure is by
utilizing vapor pressure measurements and by using expression.
π = n2 RT
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6. Continuation ;
 Where Po represent the vapor pressure of the pure solvent, P is the
vapor pressure of the solution and v is the molar volume of the solvent. As
vapor pressure can be measured with less effort than osmotic pressure this
expression is frequently used.
 Osmotic pressure for soluble solutes is extremely high. This high osmotic
pressure is responsible for high water flow across semipermeable
membrane.
 The rate of water flow by osmotic pressure can be given by following
equation.
 Where dv/dt represents the water flow across the membrane, area A and
thickness I with permeability θ.
 Δπ depicts the difference in osmotic pressure between the two
solution on either side of the membrane.
π = RTIn(Po/P)/v
dv/dt = Aθπ/L
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7. Continuation ;
 When a single osmotic driving agent is used, the pumping rate of the osmotic device
(volume per unit time) is define by Q/t = PwSm [m(πs-πe)(ΔPd+ΔPe)]
 Pw is permeability of semipermeable membrane of water, Sm is effective surface area of
the membrane and Ym is osmotic reflection coefficient of the membrane.
 πs and πe are the osmotic pressure of saturated solution of osmotic driving agent and of
the environment where device is located, respectively.
 ΔPd is elevation of internal pressure generated in the drug formulation compartment as
the result of water influx into osmotic agent compartment and ΔPe is pressure required
to deform drug formulation compartment inward.
 If the net osmotic pressure gradient [ym(πs-πe)] is constant and
the hydrostatic pressure(ΔPd+ΔPe) is negligibly small, can be simplified to
Q/t = PwSm[ym(πs-πe)
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8. BASIC
COMPONENTS OF
ODDS
 DRUG
 OSMOTIC AGENT
 SEMIPERMEABLE MEMBRANE
 WICKING AGENT
 SOLUBILIZING AGENT
 SURFACTANTS
 COATING SOLVENTS
 PLASTICIZERS
 FLUX REGULATORS
 PORE FORMING AGENT
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9.  Drug itself may act as an osmogen and shows good
aqueous solubility.
 But if the drug does not possess an osmogenic
property, osmogenic salt and other osmotic sugars can
be incorporated in the formulation.
 Drug should have short half-life 2-6 hrs.
 Used for prolonged treatment.
 Solubility of drug should be moderate (i.e not be very
high or very low).
Examples :- Nifedipine , Metoprolol , Verapamil
1)DRUG :-
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10. 2) OSMOTIC AGENT :-
 Also called Osmogens (or) Osmogents. It is responsible
for creating osmotic pressure inside the system.
 If solubility of drug is low, then drug will show slow rate
zero order release. The osmotic agent is used to enhance
the release rate by creating very high osmotic pressure
gradient inside the system.
 Types of Osmotic agents :-
Water soluble salts of Inorganic acids: Magnesium
sulphate, NaCL, KCL, Sodium bicarbonate, Sodium sulphate.
Water soluble salts of organic acids: Potassium
acetate, Magnesium succinate, Sodium citrate, Sodium
benzoate.
Carbohydrates : Mannose, Sucrose, Maltose,
Lactose.
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11. 3)
SEMIPERMEABLE
MEMBRANE :-
 It is made up of polymer, that is permeable to water but
impermeable to solute(drug & excipients), can be used as
coating material in osmotic devices.
 CRITERIA : -
 Semipermeable membrane must have sufficient wet strength
and water permeability so that it retain its
dimensional integrity throughout the operational lifetime
of device.
 Should stable both outside and inside environment of device.
 Should be Biocompatible and rigid.
Examples :-
Cellulose Acetate, Cellulose Triacetate, Ethyl Cellulose.
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12. 4) WICKING AGENT :-
 A wicking agent is defined as a material with the
ability to draw water into the porous network of
delivery device.
 A wicking agent is of either swellable (or) non-
swellable nature.
 The function of the wicking agent is
to draw water to surfaces inside the core of the
tablet, thereby creating channels (or) a
network of increased surface area.
Examples :- SLS, PVP, Bentonite.
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13. 5) SOLUBILIZING
AGENT :-
 Non-swellable solubilizing agent are classified into
three groups,
 Agents that inhibits crystal formation of the drugs (or)
otherwise act by complexation of drug.
Example :- PVP
 A high HLB micelle forming surfactant, particularly
anionic surfactants.
Example :- Tween 20, 60, 80
 Citrate esters and their combinations with anionic
surfactants.
Example :- Alkyl esters.
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14. 6) SURFACTANTS :-
7) COATING
SOLVENTS :-
 They are added to wall forming agents.
 The surfactants act by regulating the surface energy of
materials to improve their blending in to
the composite and maintain their integrity in the
environment of use during the drug release period.
Examples :- poly oxyethylenated castor oil.
 Solvents suitable for making polymeric solution that is
used for manufacturing the wall of osmotic device
include inert Inorganic and Organic solvents.
Examples :- Acetone : Water (90:10),
Acetone : Methanol (80:20).
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15. 8) PLASTICIZERS :-
9) FLUX REGULATOR :-
 Plasticizers increase the workability, flexibility and permeability
of the fluids.
 Permeability of membranes can be increased by adding plastic
which increases the water diffusion coefficient.
Examples :- Phthalates, Benzoates, TEC.
 Flux regulating agents/Flux enhancing agents/Flux decreasing
agents are added to the wall forming material; it assists in
regulating fluid permeability through membrane.
Examples :- Poly propylene, Poly butylene.
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16. 10) PORE FORMING
AGENT :-
 These agents are particularly used in the pumps
developed for poorly water soluble drug and in
the development of controlled porosity.
 These pore-forming agents cause the formation of
micro porous membrane.
Examples :- Calcium nitrate, Sucrose, Sorbitol,
Mannitol, Mannose, Potassium sulphate
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17. ADVANTAGES
 It gives zero order release profile after an initial lag.
 Drug release is independent of gastric PH, GI motility and
hydrodynamic condition.
 Enhanced Bioavailability of drug and reduced interpatient variability.
 Decrease dosing frequency.
 Improve patient compliance.
 Ease of administration.
 Greater effectiveness in the treatment of chronic conditions.
 Production scale up is easy.
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18. DISADVANTAGES
Dose dumping
Expensive
Rapid development of tolerance
Hypersensitivity reaction may occur after implantation.
Integrity and consistency are difficult.
Special equipment is required for making orifice in the
system.
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20. 1. IMPLANTABLE
OSMOTIC DRUG
DELIVERY SYESTEM :-
ROSE NELSON PUMP :
 The first osmotic pump
developed in 1955 for the
delivery of drugs to the sheep
and cattle gut.
 Composed of three chambers.
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21. A. Rose Nelson pump :-
 The pump composed of three chambers : a drug
chamber, a salt chamber holding solid salt and a
water chamber.
 A semi permeable membrane separates the salt
from water chamber.
 The major problem associated with Rose Nelson
pumps was that the osmotic action begin whenever
water came in contact with the semipermeable
membrane.
 This needed pumps to be stored empty and water
to be loaded prior to use.
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22. B.(a) Higuchi Leeper osmotic pump :-
 It has no water chamber, and the activation of
the device occurs after imbibition of the water
from surrounding environment.
 Widely employed for Veterinary use. It is
either swallowed or implanted in body of an
animal for delivery of antibiotics
growth hormones to animal.
 Modification : A layer of low melting waxy
solid, is used in place of movable separator to
separate drug and osmotic chamber.
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23. B.(b) Higuchi Theeuwes osmotic pump :-
 The release of the drug from the device is governed by
the salt used in the salt chamber and the permeability
characteristics of outer membrane.
 Diffusional loss of the drug from the device is
minimized by making the delivery port in shape of a
long thin tube.
 Small osmotic pumps of this form are available under
the trade name Alzet.
 Delivery of DNA by agarose hydrogel implant
facilitate genetic immunization in cattle
by using Alzet osmotic pumps.
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24. C) ALZET OSMOTIC PUMP :-
ALZET osmotic pumps are
miniature, infusion pumps for the
continuous dosing of laboratory
animals as small as mice and young
rats. These minipumps provide
researchers with a convenient and
reliable method for controlled
agent delivery in vivo.
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25. PRINCIPLE OF OPERATION
 ALZET pumps have 3 concentric layers :
a) Rate-controlling , semi-permeable membrane
b) Osmotic layer
c) Impermeable drug reservoir
 ALZET pumps work by osmotic displacement. Water
enters the pump across the outer, semipermeable
membrane due to the presence of a high concentration
of sodium chloride in the osmotic chamber. The entry of
water causes the osmotic chamber to expand, thereby
compressing the flexible reservoir and delivering the
drug solution through the delivery portal.
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27. APPLICATIONS
 CANCER - 9 Silicone rod implants are used for delivery of
testosterone propionate in prostate cancer patients.
Eg:- Zola dex
 IMMUNIZATION - Ethylene vinyl acetate co-polymer pellets having
Bovin serum, it helps in better immune response.
 DENTAL APPLICATION - Many dental implant have developed for
local prolonged local administration.
Eg:- Stannous floride
 DIABETES – Insulin containing implants are used in diabetes for
prolonged action.
 NORCOTIC ANTAGONIST - Long term narcotic antagonist activity.
Eg:- Naltrexon
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28. REFERENCES
 Ali N., (2021), Review article on osmotic drug delivery system ,
http://dx.doi.org/10.13140/RG.2.2.13449.77920.
 Syed SM., (2015), osmotic drug delivery system, International
journal of pharmaceutical research and allied science, 4(3),
10-20.
 Keraliya RA., Patel C., Patel P., Keraliya V., Soni TG., Patel RC.,
Patel MM., (2022), osmotic drug delivery system as a part of
modified release dosage form, ISRN pharm.,
http://dx.doi.org/10.13140/RG.2.2.13449.77920.
 Gupta RN., Gupta R., Basniwal P., Rathore GS., (2010),
osmotically controlled oral drug delivery system: a review,
International journal of pharmaceutical sciences, 1(2), 269-
275.
 Khatri N., Nikram S., Bilandi A., (2016), oral osmotic drug
delivery system : a review, International journal of
pharmaceutical sciences and research, 2302-2312.
10.13040/IJPSR.0975-8232.7(6).2302-12.
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