This document discusses osmotic drug delivery systems, specifically ALZET pumps. It begins by defining osmosis and osmotic pressure, and explaining how these principles are used in osmotic drug delivery. The basic components of osmotic drug delivery systems are then outlined, including the drug, semipermeable membrane, osmogens, and coatings. ALZET pumps are introduced as implantable osmotic pumps used in laboratory animals. Factors that affect drug release from these systems include drug solubility, osmotic pressure, delivery orifice size, and membrane properties. Evaluation methods and advantages like zero-order release and long duration of action are also summarized.

1. OSMOTIC DRUG
DELIVERY SYSTEM
(ALZET PUMP)
Presented by: Bhaskar Pratap
M.PHARM. (IP)

2. LIST OF CONTENT
1. INTRODUCTION
2. PRINCIPLE OF OSMOSIS
3. BASIC COMPONENT OF OSMOTIC SYSTEM
4. CLASSIFICATION OF OSMOTIC PUMP
5. FACTOR AFFECTING RELEASE OF MEDICAMENT
FROM OSMOTIC DDS
6. EVALUATION
7. ADVANTAGES
8. DISADVANTAGES

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.
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.
Introduction

4. 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
Where
n2 :- represents the molar concentration of sugar (or other solute) in
the solution
R:- depicts the gas constant
T:- the temperature.
Principle Of Osmosis

5. 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 rigid
Should be sufficient thick to withstand the pressure within the
Any polymer that is permeable to water but impermeable to
solute can be used as a coating material in osmotic devices
Ex. Cellulose Acetate, Cellulose Triacetate and Ethyl
Cellulose
Basic Component Of Osmotic DDS Device

6. 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 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)

7. 1. Implantable Osmotic Drug Delivery System
2. Oral Osmotic Drug Delivery System
Classification Of Osmotic DDS

8. ALZET OSMOTIC PUMP
 Design: Empty reservoir within the core of the pump is filled with the drug
or hormone solution to be delivered and is surrounded by salt chamber with
Impermeable layer between them
 It is an implantable osmotic pumps for laboratory animal
 The pump are used to deliver homogenous solution or suspension
continuously at a controlled rate for extended time
 Mechanism: water enters into the salt chamber through semi permeable
membrane and causes compression of flexible reservoir and delivery of drug
solution

9. ALZET PUMP

10. SIZES
 Nominal Performance (at 37°C)
 Pumping Rate 5.0 µl/hr (± 0.75 µl/hr)
 Duration 14 days
 Reservoir Volume 2000 µl (2.0 ml)

11. A. Solubility
B. Osmotic pressure
C. Delivery orifice
D. Membrane
A.Solubility
1. Solubility of drug is one of the most important factors since kinetic
of osmotic release is directly related to the drug solubility.
2. Both highly soluble and poorly soluble drugs are not good
candidates for osmotic drug delivery.
Factors Affecting Release Of Medicament From
Osmotic DDS

12. B. Osmotic pressure
1. The next release-controlling factor that must be optimized is the
osmotic pressure gradient between inside the compartment and the
external environment.
2. The release rate of a drug from an osmotic system is directly
proportional to the osmotic pressure of the core formulation
C. Delivery orifice
1. To achieve an optimal zero order delivery profile, the orifice must be
smaller .
2. The typical orifice size in osmotic pumps ranges from 600µ to 1
mm.

13. D. Membrane
1. Type and nature of polymer
- polymer that is permeable to water but impermeable to solute can be
selected
Ex. cellulose esters such as cellulose acetate, cellulose diacetate, cellulose
triacetate, cellulose propionate, cellulose acetate butyrate
2. Membrane thickness
- release rate from osmotic systems is inversely proportional membrane
thickness
3. Wet strength
4. Water permeability

14. EVALUATION
1.Invitro Evaluation -in vitro release of drugs from oral
osmotic systems is by
• conventional USP paddle
• basket type apparatus. The dissolution medium is
- distilled water
- gastric fluid (for first 2-4 h)
- intestinal fluids (for subsequent hours)
2.In Vivo Evaluation Of Oral Osmotic Systems
• in dogs(preferred)
• Monkey

15. 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
Advantages

16. 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
Disadvantages

17. Thank You