PULMONARY DRUG TARGETING

Presented By:Mr. Mahesh A. Marathe.

M. Pharm. Sem II (Pharmaceutics)Roll No. 514.

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Pulmonary drug delivery can be use as an alternative to oral delivery. Also used for both local and systemic actions.

Pulmonary route enhanced bioavailability, reduced toxic effect of other delivery.

The important requirement of a pulmonary delivery system is to provide perfect deposition of drug in lungs.

Due to advancement of devices in pulmonary delivery, it is possible to deliver larger doses into the lung.

Optimum particle size is important for targeting of drug to lungs. If the particle size is too small they will exhale and if it is too large, they may affect the oropharynx and larynx.

INTRODUCTION

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The respiratory tract is divided into upper and lower parts.

The terminal parts of lower respiratory tract is the bronchi & alveoli.

The alveoli are the functional unit of lungs.

Alveolar cells are divided in two types type I or type II.

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Type I cells are small, non-phagocytic, membranous cells. These cells are approximately 5 μm in thickness.

Type II cells are large, granular, epithelial cells. These cells are approximately 10 to 15μm in thickness.

The alveoli consist of surface active lining component which contains phospholipids.

Presence of this surface active lining affects compound solubility and can produce interaction of drug with cell surfaces and receptors.

The surface active lining possesses anti-inflammatory property.

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Advantages of pulmonary drug delivery

Quick onset of action.

Ease and convenience of administration

Avoids first pass metabolism.

Targeting can be easily achieved &Reduced side effects .

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DISADVANTAGESImproper dosing .

Stability problems.

Some drugs may produce irritation or toxicity.

Some drugs may be retained in lungs and clearance of the drug may be difficult.

Difficulty in producing optimum particle size.

Amount of drug delivered per puff is less which may be ineffective for certain Therapy.

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Mechanism involved in deposition of particles in lung

Due to air flow changes.

Due to brownion motion

Due to gravitational force more than air flow

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METHODS :Micronizati

on

Spray drying

Spray freez drying

Supercritical fluid

crystallization

Double emulsion/s

ol. evap.

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DRUG DELIVERY DEVICESFor pulmonary route, drug delivery devices play an important role equivalent to that of formulation aspects.

It is difficult to administer a formulation through pulmonary route without suitable drug delivery devices. The drug delivery devices are given below.

1. Metered Dose Inhalers

2. Dry Powder Inhalers

3. Nebulizers: a)Jet Nebulizers b)Ultrasonic Nebulizers

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MDI

DPI

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JET

ULTRASONIC

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DRUG DELIVERY CARRIERS

Inert Carrier(lactose)

Biodegradable polymers(PLA,PGA)

Microparticles

Nanoparticles

Liposomes

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APPLICATION

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The drugs which produce GI irritation can be administered by pulmonary route.

One of the major difficulty in this system is achieving the optimum particle size, which determines the targeted delivery of drug to lungs.

There are number of methods like micronization, spray drying, spray freezedrying, supercritical fluid crystallization and double emulsion are available to achieve the expected particle size.

Carriers like microparticles, nanoparticles, liposomes etc. can be used in pulmonary delivery.

Conclusion

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References

V.Ravichandiran, K.Masilamani*, S.Satheshkumar, D.Joseprakash, DRUG DELIVERY TO THE LUNGS, International Journal of Pharmaceutical Sciences Review and Research,volume 10,Oct.2011

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