DIPAK Kumar DASHHIMALAYAN PHARMACY INSTITUTE,SIKKIMM.PHARM PHARMACEUTICS

MAGNETIC MICROSPHERE

INTRODUCTIONMicrosphere are small in soluble spherical particle consisting of polymer matrix. Particles size ranges from 50nm to 2mmMagnetic microsphere use for drug targeting.

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MAGNETIC MICROSPHERE

Magnetic microspheres are supramolecular particles that are small enough to circulate through capillaries without producing embolic occlusion but are (ferromagnetic) to be captured in micro vessels. dragged in to the adjacent tissues by magnetic fields of 0.5-0.8 tesla (T)

CONCEPT

The use of magnetic force for site-specific drug delivery by using albumin microspheres containing magnetite appears to be a promising strategy.Significant improvements in response can be incorporated and obtained with magnetic albumin microspheres delivery system compared with conventional and nonmagnetic microspheres drug regimens.

HISTORY OF MAGNETIC GUIDANCE

Tyle 1988

Earliest use of magnet for selective delivery of clinical agents involved treatment of arterial thrombosis by use of carbonyl iron.

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MAGNETIC MICROSPHERE

MAGNETITE

Magnetite a ferromagnetic materials when incorporated in to microspheres makes them magnetically responsive so that they can be concentrated to the desired site by applying some magnetic field.Fe3O4

Ferromagneticmicrospheres(20-30 mm)

Tumor

Catheter

Artery

Microsphere

Alternating magnetic field

Alternating magnetic field

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PREPARATION

There is mainly 2 method of microsphere preparation.1. Phase separation emulsion polymerisation.2. Continuous solvent evaporation.

PHASE SEPARATION EMULSION POLYMERISATION

ALBUMIN+DRUG+MAGNETITE+VEGETABLE OIL SOLUTION

HEAT

SUSPENSION SEPARATED FROM OIL STORE AT 40C

CONTINUOUS SOLVENT EVAPORATIONVOLATILE ORGANIC

SOLVENT+POLYMER+DRUG+MAGNETITE

STIRRING

CENTRIFUGED AND MICROSPHERE SEPARATED AND STORED

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ANALYSIS OF MOVEMENT

ADVANTAGES

It allows high local concentration of therapeutic agents.

Controlled drug release within target tissue for intervals of 30 min to 30 hour, as desired

Avoidance of drug toxicity Adaptable to any part of the body

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Advance of magnetic microsphere

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Magnetic targeting is an expensive aspect.

Technical approach , manufacturing and quality control should be highly specialized.

Its needs specialized magnet for targeting & advance technique for monitoring.

Trained personnel to perform procedures.

DISADVANTAGES

APLICATION

It is use for drug targeting.Magnetic fluid hyperthermia.High throughput DNA isolation.Improvement in drug release.

REFERENCESY.W. Chien, Concepts and system design for the rate-controlled drug delivery, Drug and pharmaceutical sciences, Marcel Dekker Inc. York, 2nd Edn. 50 (1992): pp. 1-139.

S.P. Vyas & R.K. Khar, Targeted and Controlled Drug Delivery.1st edn, CBS publisher & distributor New Delhi.H.A. Lieberman, M.R. Martin & G.S. Banker, Pharmaceutical dosage forms: Disperse Systems vol-2.American journal of pharmaceutical sciences.www.dogpile.comwww.pubmed.com