This document provides an overview of osmotic drug delivery systems. It discusses the history, principles, components, advantages, and types of osmotic pumps. Some key points include: Osmotic pumps use osmotic pressure to control drug release rates; They were first developed in the 1950s and improved upon in the 1970s; Common components include semipermeable membranes, osmogens, and drug formulations; Advantages include zero-order release and increased bioavailability; Types discussed are Rose-Nelson, Higuchi-Leeper, Higuchi-Theeuwes, sandwiched osmotic tablets, and controlled porosity osmotic pumps.

1. A Seminar On
Osmotic Drug Delivery
System
Presented by
Bobade Rutuja
(M pharm sem 2)
Guided by
Prof. R. S Bandal
Department Of Quality Assurance Technique
SVPM Ꞌs College of pharmacy, Malegao (Bk)

2. CONTENTS
 Introduction
 History
 Principle
 Basic components
 Advantages
 Disadvantages
 Types of osmotic pumps

3. 1.Osmotic drug delivery uses the
osmotic pressure for controlled delivery
of drugs by using osmogens.
2. Osmosis : It refers to the process of
movement of solvent from lower
concentration of solute towards higher
concentration of solute across the
semipermeable membrane.

4. 3. Osmotic pressure: The pressure
exerted by the flow of water through a
semipermeable membrane separating
two solutions with different
concentrations of solute
4. These systems can be used for
both route of administration i.e. oral
and parenterals.

5. HISTORY OF OSMOTIC
DRUG DELIVERY SYSTEM
 About 75 years after discovery of the osmosis
principle, there was clear in the design of drug
delivery systems. Rose and Nelson, the
Australian scientists, were initiators of osmotic
drug delivery. In1955- they developed an
implantable pump, which consisted of three
chambers: a drug chamber, a salt chamber
contains excess solid salt, and a water chamber.
 In1975- the elementary osmotic pump for oral
delivery of drugs was introduced. The pump
consists of osmotic core containing the drug,

6. surrounded by a semipermeable membrane
with a delivery orifice. When this pump is
exposed to water, the core imbibes water
osmotically at a controlled rate, determined
by the membrane permeability to water and
by the osmotic pressure of the core
formulation. As the membrane is non-
expandable, the increase in volume caused
by the imbibitions of water leads to the
development of hydrostatic pressure inside
the tablet. This pressure is relieved by the
flow of saturated solution out of the device
through the delivery orifice.

7. In1970s- implantable osmotic pumps were a
major breakthrough to deliver wide range of
drugs and hormones, including peptides at
constant and programmed rate.
Osmotic pressure is used as the driving
force for these systems to release the drug
in a controlled manner. Osmotic pump tablet
(OPT) generally consists of a core including
the drug(s), an osmotic agent, other
excipients.

8.  Abbe Nollet first reported osmotic effect in
1748, But Pfeffer in 1877 had been the
pioneer of quantitative measurement of
osmotic effect.
 Van’t Hoff established the analogy between
the Pfeffer results and the ideal gas laws by
the expression-
π = n2RT
.

9. Where,
n2=Molar concentration of sugar (or
other solute) in the solution,
R depicts the gas constant and,
T the temperature.

10. 1. Drug:
Itself may act as osmogen otherwise
osmogenic salt can be added in
formulation.
2. Semipermeable membrane criteria:
Sufficient wet strength and water
permeability Should be biocompatible and

11. rigid Should be sufficient thick to withstand
the pressure.
3. Hydrophilic and hydrophobic polymers:(
CMC, HEC, HPMC )
4. Wicking agent : ( SLS, PVP, bentonite )
5.Solubilizing agent :(PVP, CD, PEG )
6.Osmogens:( NACL, KCL)
7.Surfactants : (poly oxyethylenated
caster oil)
8.Coating solvent : ( acetone and
methanol

12. 3. Hydrophilic and hydrophobic polymers:( CMC,
HEC, HPMC )
4. Wicking agent : ( SLS, PVP, bentonite )
5. Solubilizing agent :(PVP, CD, PEG )
6. Osmogens:( NACL, KCL)
7. Surfactants : (poly oxyethylenated caster oil)
8. Coating solvent : ( acetone and methanol

13. 80:20,acetone and water (90:10 )
9. Plasticizer:(phthalates, benzoates, TEC
10.Flux regulator : ( poly propylene, poly
butylene )
11.Pore forming agent:( Calcium nitrate ,
potassium sulphate)

14. List of drugs carrier in ODDS
 Diltiazen
 Hydrochloride
 Nefidipine
 Glipizide
 Carbamazepine
 Metoprolol

15. Selection criteria of drug for ODDS
 1. It should have short half-life.
 2. Prolonged release of drug should be desired.
 3. It should be potent in nature.
 4. Solubility of drug should not be very high or very
low

16. ADVANTAGES
1. Zero order release
2. High release rate
3. High degree of IVIVC
4. Production scale up is easy
5. Increase efficacy of drug
6. Controlled drug delivery
7. Reduce dosing frequency

17. 8. Release rate of drug is highly predictable and
programme.
9. Decrease dosing frequency
10. Improved patient compliance .
11. Enhanced bioavailability of drug.

18. DISADVANTAGES
1. Expensive
2. Chance of toxicity due to dose dumping
3. Release of drug depends on : - size of drug port
- surface area - thickness and composition of
membrane

19. TYPES OF OSMOTIC PUMPS
1. Rose-Nelson Pump
2. Higuchi-Leeper Osmotic Pump
3. Higuchi-Theeuwes Osmotic Pump
4. Sandwiched Osmotic Tablet (SOT)
5.Controlled Porosity Osmotic Pump
(CPOP)

20. 1. Rose-Nelson Pump
 Rose and Nelson, the Australian scientists, were initiators of
osmotic drug delivery. In 1955, they developed an implantable
pump for the delivery of drugs to the sheep and cattle gut [16].
 The Rose-Nelson implantable pump shown in Figure 2 is
composed of three chambers: a drug chamber, a salt chamber
holding solid salt, and a water chamber. A semipermeable
membrane separates the salt from water chamber. The
movement of water from the water chamber towards salt
chamber is influenced by difference in osmotic pressure
across the membrane. Conceivably, volume of salt chamber
increases due to water flow, which distends the latex
diaphragm dividing the salt and drug chambers: eventually, the
drug is pumped out of the device.

21. Fig.Rose Nelson Pump

22.  The kinetics of pumping from Rose Nelson pump is given by
the following equation:
 dMtdt=(dVdt)⋅C,
 (1)
 where dMt/dt is the drug release rate, dV/dt is the volume flow
of water into the salt chamber, and Crepresents the
concentration of drug in the drug chamber.
 dMtdt=AθΔπCl,
 (2)
 where, A is the area of semi permeable membrane, Δπ is the
osmotic pressure gradient, θ is the permeability of
semipermeable membrane, and l is the thickness of semi
permeable membrane.

23. 2. Higuchi-Leeper Osmotic Pump
 Higuchi and Leeper have proposed a number of
variations of the Rose-Nelson pump and these designs
have been described in US patents, which represent the
first series of simplifications of the Rose-Nelson pump
made by the Alza Corporation.
 The Higuchi-Leeper pump has no water chamber, and the
activation of the device occurs after imbibition of the water
from the surrounding environment.
 This variation allows the device to be prepared loaded
with drug and can be stored for long prior to use. Higuchi-
Leeper pumps contain a rigid housing and a semi
permeable membrane supported on a perforated frame; a
salt chamber containing a fluid solution with an excess of
solid salt is usually present in this type of pump.

24.  Upon administration/implantation, surrounding
biological fluid penetrates into the device through
porous and semipermeable membrane and dissolves
the MgSO4, creating osmotic pressure inside the
device that pushes movable separator toward the drug
chamber to remove drug outside the device.
 It is widely employed for veterinary use.
 This type of pump is implanted in body of an animal
for delivery of antibiotics or growth hormones to
animals .

25. Fig. Higuchi-Leeper osmotic pump

26. 3. Higuchi-Theeuwes Osmotic Pump
Higuchi and Theeuwes in early 1970s developed
another variant of the Rose-Nelson pump, even
simpler than the Higuchi-Leeper pump
Fig.Higuchi Theeuwes Pump

27.  In this device, the rigid housing consisted of a
semipermeable membrane.
 This membrane is strong enough to withstand the pumping
pressure developed inside the device due to imbibition of
water.
 The drug is loaded in the device only prior to its application,
which extends advantage for storage of the device for longer
duration.
 The release of the drug from the device is governed by the
salt used in the salt chamber and the permeability
characteristics of the outer membrane .

28. Small osmotic pumps of this form are available
under trade name Alzet made by Alza Corporation
in 1976. They are used frequently as implantable
controlled release delivery systems in experimental
studies requiring continuous administration of
drugs. Such a implantable Alzet pump is shown
in Figure
Fig.Alzet pump

29. 4. Sandwiched Osmotic Tablet (SOT)
 Sandwiched osmotic tablet is composed of polymeric
push layer sandwiched between two drug layers with
two delivery orifices.
 When placed in the aqueous environment, the middle
push layer containing the swelling agents' swells and
the drug is released from the two orifices situated on
opposite sides of the tablet; thus sandwiched osmotic
tablets (SOTS) can be suitable for drugs prone to
cause local irritation of the gastric mucosa.

30. Fig. of sandwiched osmotic pump
before and during operation.

31. 5.Controlled Porosity Osmotic Pump (CPOP)
It is an osmotic tablet wherein the delivery orifices
(holes) are formed in situ through leaching of water
soluble pore-forming agents incorporated in
semipermeable membrane (SPM) (e.g., urea,
nicotinamide, sorbitol, etc.).
Drug release rate from CPOP depends on various
factors like coating thickness, solubility of drug in
tablet core, level of leachable pore-forming agent(s)
and the osmotic pressure difference across the
membrane.

32. Fig. controlled porosity osmotic pump

33. REFERANCE
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