Osmotic DDS.pptx

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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

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INTRODUCTION

Π = p c RT

Where,

 _{p = Osmotic pressure}  _{Π = osmotic coefficient}  _{c = molar concentration}  _{R = gas constant}

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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

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DISADVANTAGES

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CLASSIFICATION

Single osmotic pump Single osmotic pump Elemantary osmotic pump (EOP) Controlled porosity osmotic pump Osmotic bursting osmotic pump Multi-chamber osmotic pump Multi-chamber osmotic pump Push pull osmotic pump (PPOP) Sandwich osmotic tablets (SOTS) Oral osmotic capsules Oral osmotic capsules OROS- CT L- OROS Pelleted delayed release Assymetric membrane capsule Implantable osmotic system Implantable osmotic system DUROS osmotic pump ALZET osmotic pump

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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

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BASIC COMPONENTS

 Drug

 Osmotic agent

 Semipermeable membrane

 Coating material

 Hyrophilic and hydrophobic polymers

 Wicking agents

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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

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OSMOTIC AGENTS

 The osmotic water flow across a membrane is given by the equation,

dv/dt = Aθ∆π

l

 Where,

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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

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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}

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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

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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

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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

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RECENTLY IN USE OSMOTIC PUMP

Drug solution leaving via delivery portal

Removable cap

Flow moderator

Semipermeable membrane

Osmotic agent

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Fig. : EOP

Limitations:

• SPM should be 200-300μm thick to withstand pressure • Thick coatings lowers the water permeation rate

• Applicable mostly for water soluble drugs

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CONTROLLED POROSITY

OSMOTIC PUMP

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

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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.

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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

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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

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DUROS OSMOTIC PUMP

 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.

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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.

 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

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MARKETED

FORMULATIONS

Brand name

Efidac 24®

Acutrim ®

Sudafed 24®

API

Chlorpheniramine Chlorpheniramine Phenylpropanolamine Phenylpropanolamine Pseudoephedrine Pseudoephedrine

Manufacturer

Novartis / Pfizer / Alza

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MARKETED

FORMULATIONS

Brand name

Ditropan XL ®

Glucotrol ®

Procardia XL®

Covera HS ®

API

Oxybutynin chloride Oxybutynin chloride Glipizide Glipizide Nifedipine Nifedipine Verapamil HCl Verapamil HCl

Manufacturer

Alza Alza

Pfizer / Alza

Novartis / Alza

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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

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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

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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

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REFERENCES

 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. 2nd Edition 1991, Varghese publishing

house, Pg. 455.

 Aulton M. E., pharmaceutics the science of dosage form design.

2nd 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.

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

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),

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

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

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