This document discusses magnetic microspheres, which are small polymer particles containing magnetite that can be used for targeted drug delivery. Magnetic microspheres are small enough to circulate but can be dragged to nearby tissues using external magnetic fields. They allow high local drug concentrations at targeted sites with controlled release over 30 minutes to 30 hours. Magnetic microspheres are prepared using phase separation emulsion polymerization or continuous solvent evaporation techniques. However, magnetic targeting requires specialized equipment and trained personnel.

1. DIPAK Kumar DASH HIMALAYAN PHARMACY INSTITUTE,SIKKIM M.PHARM PHARMACEUTICS

2. MAGNETIC MICROSPHERE

4. Particles size ranges from 50nm to 2mm

10. MAGNETIC MICROSPHERE 9

12. Alternating magnetic field Ferromagnetic microspheres (20-30 mm) Microsphere Artery Catheter Tumor Alternating magnetic field 12

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

14. PHASE SEPARATION EMULSION POLYMERISATION ALBUMIN+DRUG+MAGNETITE+VEGETABLE OIL SOLUTION HEAT SUSPENSION SEPARATED FROM OIL STORE AT 40C

15. CONTINUOUS SOLVENT EVAPORATION VOLATILE ORGANIC SOLVENT+POLYMER+DRUG+MAGNETITE STIRRING CENTRIFUGED AND MICROSPHERE SEPARATED AND STORED

16. ANALYSIS OF MOVEMENT 16

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

19. Avoidance of drug toxicity

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

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

24. Trained personnel to perform procedures. DISADVANTAGES 19

26. Magnetic fluid hyperthermia.

27. High throughput DNA isolation.

29. REFERENCES Y.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.com www.pubmed.com