Stimulli Activated Drug Delivery System.pptx

Stimuli Activated Drug Delivery System

1. ACTIVATION MODULATED DRUG DELIVERY SYTEM Presented by: Under the guidance of : Sonal Mehrotra Dr. Srinivas Mutalik M.Pharm , Part-1, HOD, Pharmaceutics Dept. of Pharmaceutics MCOPS, Manipal MCOPS, Manipal

2. CONTENTS:- Theme Question-01 Theme Question-02 Introduction Classification Various physical activated system Various chemical activated system Various biochemical activated system References 2

3. THEME QUESTION -01 What is DRUG DELIVERY SYSTEM? 3

4. THEME QUESTION- 02 What is CONTROLLED DRUG DELIVERY SYSTEM? 4

5. INTRODUCTION Type of controlled release dosage form Definition:- DDS is activated by:- Physical process Chemical process Biochemical process And facilitated by the energy supplied externally. The rate of drug release is then controlled, based on the nature of the process applied or the type of energy used. 5

6. CLASSIFICATION 6

7. Physical Means:- 7

8. Osmotic pressure-activated DDS: This type of activation-controlled delivery system depends on osmotic pressure to activate the release of drug. To release in solution form at a constant stem The drug reservoir -A solution -A solid formulation Contained within a semipermeable housing with a controlled water permeability. The drug in solution form, released through a special laser-drilled delivery orifice. Constant rate of drug release is under controlled gradient of osmotic pressure. Examples:- Alzet osmotic pump [IMPLANTABLE] Acutrim tablet [ORAL RATE CONTROLLED DDS ] 8

9. Schematic representation of the basic model of osmotic pressure-activated DDS Where, v s is volume of osmotic agent compartment v d is volume of drug compartment 9

10. For DDS containing a solution formulation, the intrinsic rate of drug release Q/t is defined by: For DDS containing a solid formulation, the intrinsic rate of drug release Q/t is defined by : Where, Pw, Am & hm are the water permeability, effective surface area & thickness of the semipermeable housing, respectively; ( π s- π e) is differential osmotic pressure between the drug delivery system & environment & Sd is the aqueous solubility of drug contained solid formulation 10

11. The release of drug molecule from this type of delivery system is activated by osmotic pressure and controlled at a rate determined by:- The water permeability The effective surface area of the semipermeable membrane Osmotic pressure gradient Representative of this type of delivery systems are as follows: 11

12. Example: Alzet Osmotic Pump Implantable or insertable CrDDS . Alzet Pumps have 3 osmotic layer:- Rate-controlling, semipermeable membrane Osmotic layer Impermeable drug reservoir The drug reservoir is contained within a collapsible, impermeaable polyester bag. Principle of Operation:- ALZET pumps works by osmotic displacement. Water enters the pump across the outer, semi-permeable membrane due to the presence of a high osmotic chamber. The entry of water causes the osmotic chamber to expand, thereby compressing the flexible reservoir. Delivering the drug solution through the delivery portal. 12

13. Hydrodynamic Pressure- activated DDS: A drug reservoir compartment ( a liquid drug formulation inside a collapsible, impermeable container). Contained inside a rigid, shape- retaining housing. A laminate of an absorbent layer and a swellable , hydrophilic polymer layer is sandwiched between the drug reservoir compartment and the housing. In the GIT, the laminate will imbibe the gastrointestinal fluid- -through the annular openings at the lower end of the housing and become swollen. Generates a hydrodynamic pressure in the system. Contdd …… 13

14. Forces the drug reservoir compartment to reduce in volume. Causes the liquid drug formulation to release through the delivery orifice. View of a hydrodymanic pressure activated system In this type the hydrodynamic pressure is used as a source of energy to activate the drug release. 14

15. The rate of drug release is defined by following equn :- Where, Pw, Am , & hm are the fluid permeability, the effective surface area and the thickness of the wall with annular opening respectively. The ( Ө s- Ө e) is the difference in hydrodynamic pressure between the drug delivery system and the environment. Controlled release rate is determined by:- Fluid permeability. Effective surface area. Hydrodynamic pressure gradient . 15

16. Vapor Pressure-activated DDS: The drug reservoir (a solution formulation contained inside the infusion compartment). Physically separated from the pumping compartment by a freely movable partition. The pumping compartment contains:- A vaporizable fluid, such as fluorocarbon 16

17. The delivery of drug - Activated by vapor pressure - Controlled at a rate determined by: - The differential vapor pressure - The formulation viscosity - The size of delivery cannula Example: Implantable infusion pump ( infusaid ) for the constant infusion of:- Heparin in anticoagulant treatment Insulin in anti-diabetic treatment Morphine for the intense pain of terminal cancer. 17

18. Mechanically Activated DDS: The drug reservoir (solution formulation retained in a container equipped mechanically activated pumping system). A measured dose of drug formulation: - Delivered to body cavity such as nose, through the spray head - Upon manual activation of pumping system. The volume of solution delivered is small ( 10-100µl ). Independent of the force and duration of activation. Example: ( MDI) For the intranasal administration of a precision dose of : - Buserelin - Insulin 18

19. Magnetically Activated DDS: The drug reservoir is dispersion of peptides or protein powder in a polymer matrix from which drug can be delivered relatively at slow rate. Can be improved by electromagnetism-triggering vibration mechanism & with a hemisphere- shaped design, a zero order drug release is achieved. Hemisphere devices can release macromolecular drug -At low rate, by diffusion process. - At high rate, when magnet is activated, to vibrate by external electromagnetic field. 19

20. Factors affecting:- - Strength of magnetic field - Mechanical properties of the polymer matrix Example: Used to deliver protein drugs such as BOVINE SERUM ALBUMIN. 20

21. Sonophoresis Activated DDS: This type of activation controlled drug delivery system utilizes ultrasonic energy to activate (or trigger) the delivery of drug from polymeric drug delivery devices. 21

22. This system can be fabricated from either a non-biodegradable polymer such as ethylene- vinyl acetate co polymer or a bio-erodible polymer. Example: It has been explored to promote ocular drug delivery Application of ultrasound to activate the delivery of drug 22

23. Iontophoresis activated DDS: Primarily used in transdermal delivery. In this, delivery system uses electrical current to activate & to modulate the diffusion of the charged drug molecules across the skin. The iontophoresis facilitated skin permeation rate of a charged molecules. Basic Mechanism :- “Like charges repel and opposite charges attract.” Positively charged drugs are paced at positive pole, while negatively charged peptides are placed at negative pole. Electrorepulsion of like charges and attraction of opposite charges push the drug across the membrane. 23

24. cntd … Example: Iontophoresis DDS to facilitate the percutaneous penetration of Dexamethasone sodium phosphate (anti-inflammatory). Representation of iontophoresis activated system 24

25. Hydration Activated DDS: In this the drug reservoir is homogenously dispersed in a swellable polymer matrix fabricated from hydrophilic polymer (ethylene glycomethacrylate ). The release of drug is controlled by the rate of swelling of the polymer matrix. Example :- Norgestomet releasing HYDRON implant - The VALRELEASE tab Hydration-induced formation of colloidal gel barrier 25

26. Chemical Means:- 26

27. pH Activated DDS: This system permits targeting the delivery of a drug only in the region with a selected pH range. Fabricated by coating the drug core with a pH sensitive polymer Example :- 27

28. ctnd … pH – dependent formation of micro-porous membrane Note: By adjusting the ratio of intestinal fluid soluble polymer to the intestinal fluid insoluble polymer, the membrane permeability is modified. . 28

29. Ion-Activated DDS: 29

30. cntd …. H + + Resin- SO 3 ‾ * Drug + Resin-SO 3 ‾ *H + + Drug ‾ Cl ‾ + Resin-[N{CH 3 } 3 ] + * Drug‾ [N{CH 3 } 3 ] + * Cl ‾ + Drug + Diagram of Ion-activated drug release 30

31. Hydrolysis-Activated DDS: This type of system depends on the hydrolysis process to activate the release of drug. Drug reservoir is either encapsulated in microcapsules or homogenously dispersed in microspheres . Can also be fabricated as an implantable device. Systems prepared from biodegradable polymers. It is activated by hydrolysis-induced degradation of polymer chain & is controlled by rate of polymer degradation. Example: Releasing biodegradable subdermal implants, designed to deliver goserline for once a month treatment of prostate carcinoma. 31

32. Biochemical Means:- 32

33. Enzyme-Activated DDS: This type of biochemical system depends on the enzymatic process to activate the release of drug. Drug reservoir- - physically entrapped in microsphere or, - chemically bound to polymer chains from biopolymers(albumins or polypeptides) The release of drug is activated by enzymatic hydrolysis of biopolymers by specific enzyme in target tissue . Example: Albumin microspheres release 5- fluorouracil in a controlled manner by protease- activated biodegradation . 33

34. REFERENCES: Y.W.Chien ; Novel Drug Delivery System, 2 nd ed , pg no. 24-40 R. Tiwari ; Controlled release drug formulation in pharmaceuticals: A study on their application and properties. World Journal of Pharmaceutical Research, 5(2), 1704-1720 S.P.Vyas , K.Khar ; Controlled Drug Delivery Concepts and Advances, 1 st edition, pg no.1-41 www.google.com 34

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