Osmotic DDS.pptx

OSMOTIC DRUG DELIVERY SYSTEM

1. Osmotic DDS

2. Introduction Osmosis refers to the process of movement of solvent from lower concentration of solute towards higher concentration of solute across a semi permeable membrane till the equilibrium achieved. Osmotic pressure  is the pressure which, if applied to the more concentrated solution, would prevent transport of water across the semipermeable membrane. 2

3. Introduction Π = p c RT Where, p = Osmotic pressure Π = osmotic coefficient  c = molar concentration R = gas constant T = Absolute temperature 3

4. Advantages The delivery rate of zero-order is achievable with osmotic systems. Delivery may be delayed or pulsed, if desired. Higher release rates are possible with osmotic systems compared with conventional diffusion-controlled drug delivery systems . The release rate of osmotic systems is highly predictable and can be programmed by modulating the release control parameters. For oral osmotic systems, drug release is independent of gastric pH and hydrodynamic conditions. The release from osmotic systems is minimally affected by the presence of food in gastrointestinal tract. A high degree of in vivo- in vitro correlation (IVIVC) is obtained in osmotic systems. 5

5. disadvantages 6 Osmotic system

6. Classification 7 Oral osmotic tablet

7. Criteria for selection of a drug Short biological Half-life (2- 6 hrs) High potency Required for prolonged treatment (e.g: Nifedipine, Glipizide, Verapamil and Chlorpromazine hydrochloride). 8

8. Basic components Drug Osmotic agent Semipermeable membrane Coating material Hyrophilic and hydrophobic polymers Wicking agents Pore forming agents 9

9. Osmotic agents Osmotic pressures for concentrated solution of soluble solutes commonly used in controlled release formulations are extremely high, ranging from 30 atm for sodium phosphate up to 500 atm for a lactose-fructose mixture. These osmotic pressures can produce high water flows across semipermeable membranes . 10

10. Osmotic agents The osmotic water flow across a membrane is given by the equation, dv/dt = A θ∆π l Where, dv/dt, is the rate of water flow across the membrane of area A, thickness l, permeability θ in cm 3 , and ∆π . 11

11. Osmotic pressure of saturated solutions of commonly used pharmaceutical solutes 12

12. Osmotic pressure of saturated solutions of commonly used pharmaceutical solutes 13

13. Semipermeable membrane The membrane must possess certain performance criteria such as: Sufficient wet strength and water permeability Should be biocompatible Rigid and non-swelling 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. e.g. Cellulose esters like cellulose acetate, cellulose acetate butyrate, cellulose triacetate and ethyl cellulose and Eudragits.  14

14. Coating material Different types and amount of plasticizers used in coating membrane also have a significant importance in the formulation of osmotic systems. They can change visco-elastic behavior of polymers and these changes may affect the permeability of the polymeric films. Some of the plasticizers used are as below: Polyethylene glycols Ethylene glycol monoacetate; and diacetate- for low permeability Triethyl citrate Diethyl tartarate or Diacetin- for more permeable films 15

15. HYDROPHILIC AND HYDROPHOBIC POLYMERS These polymers are used in the formulation development of osmotic systems containing matrix core . The selection of polymer is based on the solubility of drug as well as the amount and rate of drug to be released from the pump.   16

16. WICKING AGENTS 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 are colloidon silicon dioxide, kaolin, titanium dioxide, alumina, niacinamide, sodium lauryl sulphate (SLS), low molecular weight polyvinyl pyrrolidone (PVP), bentonite, magnesium aluminium silicate, polyester and polyethylene, etc. 17

17. PORE FORMING AGENT These agents are particularly used in the pumps developed for poorly water soluble drug and in the development of controlled porosity or multiparticulate osmotic pumps. The pore formers can be inorganic or organic and solid or liquid in nature. Like, Alkaline metal salts such as sodium chloride, sodium bromide, potassium chloride, etc. Alkaline earth metals such as calcium chloride and calcium nitrate Carbohydrates such as glucose, fructose, Lactose, etc. 18

18. Osmotic pump & its component 19

19. Recently in use osmotic pump 20 Drug solution leaving via delivery portal Removable cap Flow moderator Semipermeable membrane Osmotic agent Flexible impermeable reservoir wall Reservoir

20. 21 Fig. : EOP Limitations: SPM should be 200-300 μ m thick to withstand pressure Thick coatings lowers the water permeation rate Applicable mostly for water soluble drugs Elementry osmotic pump (EOP)

21. Controlled porosity osmotic pump 22 It is laser or micro driven orifice. When Controlled Porosity Osmotic pump is placed in aqueous environment the water soluble component of coating dissolves and forms micropores in membrane and water diffuses inside the core through microporous membrane, setting up an osmotic gradiant and thereby controlling the release of drug.

22. Osmotic bursting osmotic pump Core:  API ± osmogents Coat:  Semi permeable membrane without delivery orifice When placed in aqueous environment, water is imbibed and hydraulic pressure is built up inside the system, then wall ruptures and the contents are released. It is used for pulsated release. 23

23. Push-pull osmotic pump (PPOP) Core Tablet: Layer 1:  API ± osmogents Layer 2: Polymeric osmotic agents Coat:  Semi permeable membrane with delivery orifice. It is a bilayer tablet coated with semi permeable membrane. The PPOP system consists of two compartments separated usually by an elastic diaphragm . The upper compartment contains the drug and is connected to the outside environment via a small delivery orifice. 24

24. Push-pull osmotic pump (PPOP) 25

25. Push-pull osmotic pump (PPOP) 26

26. Sandwiched Osmotic tablets (SOTS) It 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 delivery orifices. Advantage : the drug is released from the two orifices situated on opposite sides of the tablet 27

27. Sandwiched Osmotic tablets (SOTS) 28

28. Duros osmotic pump 29

29. Duros osmotic pump 30 Design : Implantable drug-dispensing osmotic pump, shaped as a small rod with titanium housing. Mechanism : Through osmosis, water from the body is slowly drawn through the semi-permeable membrane into the pump by osmotic agent residing in the engine compartment, which expands the osmotic agent and displaces a piston to dispense small amounts of drug formulation from the drug reservoir through the orifice. Application: Systemic or site-specific administration of a drug

30. Duros osmotic pump 31

31. alzet osmotic pump 32

32. alzet osmotic pump 33 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. Mechanism: Water enters into the salt chamber through semipermeable membrane and causes compression of flexible reservoir and delivery of drug solution. Application: To deliver drugs, hormones, and other test agents continuously at controlled rates from one day to six weeks.

33. LIQUID OSMOTIC SYSTEM (L-OROS) 34

34. OROS TRI-LAYER

35. 36 Osmotic tablet and recent advancement in it- Nidhi Lathia

36. Marketed formulations 37

37. Marketed formulations 38

38. FACTORS AFFECTING THE PERFORMANCE OF OSMOTIC DRUG DELIVERY SYSTEM Physico -chemical properties of the drug Solubility Solid or liquid Viscosity (Liquids) Rheological properties Properties of osmotic agent Osmotic pressure difference generated by the agent which ultimately will decide the water influx and in turn the delivery of active. Membrane type and characteristics Wet strength Water permeability Size of delivery orifice Characteristics of the polymer used (e.g. Hydration, Swelling etc.)

39. IN VITRO EVALUATION The in vitro release of drugs from oral osmotic systems has been evaluated by the conventional USP paddle and basket type apparatus. The dissolution medium is generally distilled water as well as simulated gastric fluid (for first 2-4 h) and intestinal fluids (for subsequent hours) have been used. The standard specifications, which are followed for the oral controlled drug delivery systems are equivalently applicable for oral osmotic pumps. In vivo evaluation of oral osmotic systems has been carried out mostly in dogs. Monkeys can also be used but in most of the studies the dogs are preferred.

40. Question bank What is ODDS? Why it is required? Enumerate recent advance in controlled osmotic drug delivery system with their approaches. What are ideal properties of semi permeable membrane? Suggest few materials for this. Wright note on evaluation of osmotic pump. Write a note on principle of osmotic drug delivery system.  Give advantage and disadvantage of osmotic drug delivery system. Give name of osmotic pumps. Give detail on elementary osmotic pump. 42

41. References 43 Gupta Roop, Gupta Rakesh, Basniwal Pawan k, Rathore Garvendras, Osmotically controlled oral drug delivery systems: a review, int. J. Ph. Sci., 2009, 1(2), 269-275. Gohel M.C Parikh .R.K ,  Shah. N.Y Osmotic drug delivery- an update, pharmainfo.net, 2009, 7(2). Lachman L., Liberman H. A., Kanig J. L., The theory and practise of industrial pharmacy. 2 nd Edition 1991, Varghese publishing house, Pg. 455. Aulton M. E., pharmaceutics the science of dosage form design. 2 nd Edition 2002, Churchill livingstone, Pg. 38, 39, 74, 304, 417. Ajay Babu, M. Prasada Rao, Vijaya Ratna J, Controlled-porosity osmotic pump tablets-an overview, jprhc. Shailesh Sharma. Osmotic controlled drug delivery. Pharmainfo.net. 2008; 6(3).

42. Y. W. Chien, (2005), Novel Drug Delivery System, 2nd edition, Marcel Dekker,Inc., 1-3, 17-18, 33-36. N. K. Jain and S. K. Jain, (1997), Controlled and novel Drug Delivery, 1st edition, C.B.S. publishers and distributors, 1-2. M. C. Gohel, R. K. Parikh, N.Y. Shah, (2009), Osmotic Drug Delivery: An Update. R. K. Verma, D. M. Krishna and S. Garg, (2002), Review article on Formulation aspects in the development of osmotically controlled oral drug delivery systems, J. Control. Release, 79, 7-27. N. S. Parmar S. K. Vyas, N. Vaya, (2003), Advances in Controlled and Novel Drug Delivery, CBS publishers, 18-32 44

43. S. P. Vyas, R. K. Khar, Controlled Drug Delivery Concepts and Advances, (2001), Vallabh Prakashan, 170. A.G. Thombre, A.R. DeNoto and D.G. Gibbes, (1999), Delivery of glipizide from asymmetric membrane capsules using encapsulated excipients, J. Control. Release, 60, 333-341. Partha Gan Chaudhuri, Satya Prakash Singh, A Review Of Hydrogel-A Novel Drug Delivery System. X. Li and B.R. Osmotic Controlled Drug Delivery Systems, In: Design of controlled release of drug delivery systems, McGraw Hill, 203-229. 45

44. 46 THANK YOU