This document provides an overview of osmotic controlled drug delivery systems and enzyme activated drug delivery systems. It discusses the principles of osmosis, mechanisms of osmotic controlled release, basic components of osmotic drug delivery systems, factors affecting their design, types of osmotic pumps, marketed products, advantages and disadvantages. It also briefly describes enzyme activated systems, which rely on enzymatic hydrolysis to activate the release of drugs entrapped or bound in biopolymers at target tissues. The document was presented by Sonal Sunil Salunke to Dr. Avinash Hosmani of the Department of Pharmaceutics at GCOP Karad.

1. Osmotic Controlled Drug Delivery System
And
Enzyme Activated drug delivery system
Presented by,
Sonal sunil salunke
M pharm, 1st year.
DEPT OF PHARMACEUTICS,
GCOP KARAD.
Facilitated to,
Dr. Avinash Hosmani sir;
HOD & Professor of
DEPT OF PHARMACEUTICS,
GCOP KARAD.

2. OSMOTIC DRUG DELIVERY SYSTEM
1. Introduction :-
 Osmotic drug delivery uses the osmotic pressure for controlled delivery of drugs by using
osmogens.
 Osmosis : It refers to the process of movement of solvent from lower concentration of solutes
towards higher concentration of solute across the semipermeable membrane.
 Osmotic pressure : The pressure exerted by the flow of water through a semipermeable
membrane separating two solutions with different concentration of solute.
 These systems can be used for both route of administration i.e. oral and parentrals.

3. • NEED FOR DEVELOPING DOSAGE FORM
1. To reduce dose
2. To reduce dose related side effects
3. To minimize rate of administration
4. To provide controlled release
5. To increase patient compliance

4. 2. Principle of osmosis
 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.

5. 3. Mechanism of osmotic controlled release
a) Quantative aspects of osmosis :-
Van’t Hoff described the relationship between the osmotic pressure of a
dilute solution and its concentration as follows:
V∏ = 𝑛𝑅𝑇
Where ∏ = osmotic pressure in atmosphere.
V = volume of the solution in lit.
n = no. of moles of solute.
R = gas constant.
T = absolute temp.
This equation also can be written as followes:
∏ = (n/v) RT or
∏ = cRT

6. 2) Elementary osmotic delivery system :-
 It Consist of an osmotic core containing drug & as necessary, an
osmogen surrounded by semipermeable membrane with aperture.
 The osmotic flow of the liquid depends on the osmotic & hydrostatic
pressure differences across the semipermeable membrane of the
system.
Semipermeable
membrane. (cellulose
esters)
Drug reservoir ( API osmotic
agent)
Osmotic core
Drug release

7. FACTORS AFFECTING THE DESIGN OF OSMOTIC
CONTROLLED DRUG DELIVERY SYSTEM
1. Solubility of drug
2. Osmotic pressure
3. Delivery orifice
4. Membrane type

8. 4) Basic components of osmotic DDS
a) Drug :- itself may act as osmogen otherwise osmogenic salt can be added
in formulation.
b) Semipermeable membrane : criteria : Sufficient wet strength and water
permeability should be biocompatible and rigid should be sufficient thick
to withstand the pressure within the device 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.
c) Hydrophilic and hydrophobic polymers :(CMC, HEC, HPMC)
d) Wicking agent : SLS, PVP, bentonite.
e) Solubilizing agent : PVP, CD, PEG.
f) Osmogens : NACL, KCL.
g) Surfactants : poly oxyethylenated caster oil

9. h) Coating solvent : acetone and methanol 80:20, acetone and water 90:10
i) Plasticizer : phthalates, benzoates, TEC
j) Flux regulator : poly propylene, poly butylene
k) Pore forming agent : Calcium nitrate, potassium sulphate.
6) Evaluation :
1. IN VITRO EVALUATION
2. IN VIVO EVALUATION

10. 7) TYPES OF OSMOTIC PUMPS
1. Implanted osmotic pumps
a) Rose-Nelson osmotic pump
b) Higuchi Leeper osmotic pump
c) Higuchi Theeuwes osmotic pump
d) Mini osmotic pumps
2. Oral osmotic pumps
a) Elementary osmotic pump – single chamber osmotic pump
b) Controlled porosity osmotic pump – single chamber osmotic pump
c) Push pull osmotic pump( for solid drugs) – multi-chamber osmotic pumps
d) L-OROS system( for liquid drugs) – multi-chamber osmotic pump
e) Modified osmotic pump
1. modified osmotic pump for insoluble drugs
2. modified osmotic pump for highly soluble drugs
f) Monolithic osmotic pump
g) Multi-particulate delayed release system

11. 8) MARKETED PRODUCTS
1. Products IncorporatingALZA’s OROS Technology
A. Cardura XL (doxazosin mesylate) sold in Germany for the treatment of
hypertension.
B. Covera-HS (verapamil) a controlled release system for the management
of hypertension and angina pectoris.
C. Sudafed (pseudoephedrine) for 24 hour relief of cold and other
respiratory allergies.
D. Procardia XL (nifedipin) extended-release tablet for the treatment of
angina and hypertension.
2. Product Incorporating ALZA’s DUROS Implant Technology
A. Viadur (leuprolide acetate implant) delivers leuprolide continuously for
12 months.

12. 9) 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

13. 10) 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

14. Enzyme – Activated drug delivery
system

15. Enzyme activated drug delivery system
• This type of biochemical system depends on the enzymatic process
to activate the release of drug.
• Drug reservoir is either physically entrapped in microspheres or
chemically bound to polymer chains from biopolymers (albumins or
polypeptides).
• The release of drug is activated by enzymatic hydrolysis of
biopolymers (albumins or polypeptides) by specific enzyme in target
tissue.
• Ex. Albumin microspheres release 5 - flurouracil in a controlled
manner by protease – activated biodegradation.

16. Thank
You…