MICROSPHERES AS A NOVEL DRUG DELIVERY SYSYTEM - A …

1 International Journal of ChemTech Research CODEN( USA): IJCRGG ISSN : 0974-4290 , , pp 526-534, July-Sept 2009 MICROSPHERES AS A NOVEL drug DELIVERY SYSYTEM - A *, Madhu Sudana , ,Attuluri Venkata Badarinath, and College of Pharmacy, Rajampet-516126, Andhra Pradesh State, India* Email: Tel: 91-8565-249309 mob: 91-9989530761 Abstract: MICROSPHERES are characteristically free flowing powders consisting of proteins or synthetic polymers which arebiodegradable in nature and ideally having a particle size less than 200 well designed controlled drug DELIVERY systemcan overcome some of the problems of conventional therapy and enhance the therapeutic efficacy of a given drug .

2 There arevarious approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion. One suchapproach is using MICROSPHERES as carriers for drugs. It is the reliable means to deliver the drug to the target site withspecificity, if modified, and to maintain the desired concentration at the site of interest without untoward effects. Microspheresreceived much attention not only for prolonged release, but also for targeting of anticancer drugs to the tumour.

3 In future bycombining various other strategies, MICROSPHERES will find the central place in NOVEL drug DELIVERY , particularly in diseased cellsorting, diagnostics, gene & genetic materials, safe, targeted and effectivein vivo DELIVERY and supplements as miniatureversions of diseased organ and tissues in the : MICROSPHERES , controlled release, target site, specificity, therapeutic efficacy, NOVEL drug well designed controlled drug DELIVERY systemcan overcome some of the problems of conventionaltherapy and enhance the therapeutic efficacy of a obtain maximum therapeutic efficacy.

4 Itbecomes necessary to deliver the agent to the targettissue in the optimal amount in the right period of timethere by causing little toxicity and minimal are various approaches in delivering atherapeutic substance to the target site in a sustainedcontrolled release such approach is usingmicrospheres as carriers for are characteristically free flowingpowders consisting of protiens or synthetic polymerswhich are biodegradable in nature and ideally having aparticle size less than 200 usedMicrospheres used usually are polymers.

5 Theyare classified into two polymers 1. Synthetic polymers are divided into two types. a. Non-biodegradable polymers Poly methyl methacrylate (PMMA)3 Acrolein4 Glycidyl methacrylate Epoxy polymers b. Biodegradable polymers Lactides, Glycolides & their co polymers5 Poly alkyl cyano acrylates Poly anhydrides 2. Natural polymers obtained from different sourceslike proteins, carbohydrates and chemically : Albumin6, Gelatin7, and Collagen Carbohydrates: Agarose, Carrageenan, Chitosan,Starch8 Chemically modified carbohydrates: Poly dextran,Poly starch.

6 In case of non-biodegradable drug carriers, whenadministered parenterally, the carrier remaining in thebody after the drug is completely released posespossibility of carrier toxicity over a long period of et ChemTech ,1(3)527 Bio degradable carriers which degrade in thebody to non-toxic degradation products donot pose theproblem of carrier toxicity and are more suited forparenteral polymersPoly alkyl cyano acrylates is a potential drugcarrier for parenteral as well as other ophthalmic, oralpreparations.

7 Poly lactic acid is a suitable carrier forsustained release of narcotic antagonist, anti canceragents such as cisplatin, cyclo phosphamide, anddoxorubicin9. Sustained release preparations for anti malarialdrug as well as for many other drugs have beenformulated by using of co-polymer of poly lactic acidand poly glycolic anhydride MICROSPHERES (40 m) havebeen investigated to extend the precorneal residencetime for ocular adipic anhydride is used to encapsulatetimolol maleate for ocular DELIVERY .

8 Poly acroleinmicrospheres are functional type of MICROSPHERES . Theydonot require any activation step since the surfacialfree CHO groups over the poly acrolein can react withNH2group of protein to form Schiff s polymers Albumin6 is a widely distributed natural is considered as a potential carrier of drug orprotiens (for either their site specific localization ortheir local application into anatomical discrete sites). Itis being widely used for the targeted drug for thetargeted drug DELIVERY to the tumour cells.

9 Gelatin7 MICROSPHERES can be used as efficientcarrier system capable of delivering the drug orbiological response modifiers such as interferon tophagocytes. Starch8 belongs to carbohydrate class. Itconsists of principle glucopyranose unit, which onhydrolysis yields D-glucose. It being a poly saccharideconsists of a large number of free OH groups. Bymeans of these free OH groups a large number ofactive ingredients can be incorporated within as well asactive on surface of MICROSPHERES .

10 Chitosan13 is a deacylated product of chitin. Theeffect of chitosan has been considered because of itscharge. It is insoluble at neutral and alkaline Ph values,but forms salts with inorganic and organic salts. Upondissolution, the amino groups of chitosan getprotonated, and the resultant polymer becomespositively loading and drug release kinetics The active components are loaded over themicrospheres principally using two methods, duringthe preparation of the MICROSPHERES or after the formationof the MICROSPHERES by incubating them with thedrug/protein.