Microspheres types preparation evaluation and application
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Microspheres can be used to deliver drugs in a controlled manner. They are small spherical structures made of synthetic or natural polymers. Common preparation methods include single/double emulsion techniques, polymerization, coacervation, and solvent extraction. Drugs can be loaded during or after preparation. Release depends on degradation or diffusion properties. Microspheres find applications in taste masking, converting liquids to solids, sustained release, and targeted delivery. They allow controlled and targeted drug administration.
Microspheres types preparation evaluation and application
- 1. MICROSPHERES-TYPES ,PREPARATION ,EVALUATION AND APPLICATIONS PRESENTED BY SUJITHA MARY M PHARM ST JOSEPH COLLEGE OF PHARMACY 1
- 2. CONTENTS INTRODUCTION CLASSIFICATION OF POLYMERS METHODS OF PREPARATION RELEASE FROM MICROSPHERE MECHANISAM OF DRUGCHARACTERIZATION APPLICATIONS CONCLUSION. REFERENCES 2
- 3. INTRODUCTION Definition of microspheres Microparticles or microspheres are defined as small spheres made of any material and sized from about 50 nm to about 2 mm. The term nanospheres is often applied to the smaller spheres (sized 10 to 500 nm) to distinguish them from larger microspheres. Microbeads and beads are used alternatively for microsphere 3
- 4. Ideally, microspheres are completely spherical and homogeneous in size. 4
- 5. Types of Microspheres Microcapsule: consisting of an encapsulated core particle. Entrapped substance completely surrounded by a distinct capsule wall. Types of Microspheres Microcapsule Micromatrix Micromatrix: Consisting of homogenous dispersion of active ingredient in particle 5
- 6. Polymers used in the Microsphere preparation Synthetic polymer Non-biodegradable Epoxy polymers Acrolein PMMA Biodegradable Polyanhydrides Polyalkyl cyanoacrylates Lactides and Glycolides copolymers 6
- 7. Natural Materials Proteins Collagen Gelatin Albumins Carbohydrates Chitosan Carrageenan Starch agarose Chemically modified carbohydrates Poly(acryl)starch Poly(acryl)dextran 7
- 8. GENERAL METHODS OF PREPARATION Single Emulsion techniques Double emulsion techniques Polymerization techniques - Normal polymerization. - Interfacial polymerization Coacervation phase separation techniques Solvent extraction Spray drying and spray congealing 8
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- 15. Interfacial Polymerization technique When two reactive monomers are dissolved in immiscible solvents, the monomers diffuse to the oil- water interface where they react to form a polymeric membrane that envelopes dispersed phase. Drug is incorporated either by being dissolved in the polymerization medium or by adsorption onto the nanoparticles after polymerization completed. The nanoparticle suspension is then purified to remove various stabilizers and surfactants employed for polymerization by ultracentrifugation and resuspending the particles in an isotonic surfactant-free medium. 15
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- 18. Salting-out process An aqueous phase saturated with electrolytes (e.g., magnesium acetate, magnesium chloride) and containing PVA as a stabilizing and viscosity increasing agent is added under vigorous stirring to an acetone solution of polymer. In this system, the miscibility of both phases is prevented by the saturation of the aqueous phase with electrolytes, according to a salting-out phenomenon. The addition of the aqueous phase is continued until a phase inversion occurs and an o/w emulsion is formed 18
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- 21. DRUG LOADING During the preparation of microspheres or after the formation of microspheres by incubating. Loading into preformed microspheres has an advantage of removing all impurities from microsphere preparation before the drug is incorporated High loading can be achieved by insitu loading. If the drug is insoluble in dispersion medium employed for microsphere stabilization. 21
- 22. ROUTE OF ADMINISTRATION ORAL DELIVERY PARENTERAL DELIVERY 22
- 23. MECHANISM OF DRUG RELEASE Degradation controlled monolithic system. Diffusion controlled monolithic system Diffusion controlled reservoir system. Erodable polyagent system. 23
- 25. PARTICLE SIZE 25
- 27. POTENTIAL USE OF MICROSPHERESIN THE PHARMACEUTICAL INDUSTRY Taste and odour masking. Conversion of oils and other liquids to solids for ease of handling Protection of drugs against the environment (moisture, light etc.). Separation of incompatible materials (other drugs or excipients). Improvement of flow of powders Aid in dispersion of water-insoluble substances in aqueous media, and Production of SR, CR, and targeted medications. 27
- 28. OTHER APPLICATIONS Microcapsules are also extensively used as diagnostics, for example, temperature-sensitive microcapsules for thermographic detection of tumors. In the biotechnology industry microencapsulated microbial cells are being used for the production of recombinant proteins and peptides. Encapsulation of microbial cells can also increase the cell- loading capacity and the rate of production in bioreactors. A feline breast tumor line, which was difficult to grow in conventional culture, has been successfully grown in microcapsules. Microencapsulated activated charcoal has been used for hemoperfusion. 28
- 29. These Microspheres are free-flowing and roll with practically no friction, that means there is no abrasion, guaranteeing a dust-free environment. These carriers received much attention not only for prolonged release but also for the targeting anti cancer drugs to the tumour. Solid biodegradable microspheres incorporating a drug dispersed or dissolved throughout particle matrix have the potential for controlled release of the drug. Microspheres are made from polymeric , waxy or protective materials that is biodegradable synthetic polymers and modified natural products. 29
- 31. CONCLUSION The concept of microsphere drug delivery systems offers certain advantages over the conventional drug delivery systems such as controlled and sustained delivery. Apart from that microspheres also allow drug targeting to various systems such as ocular , intranasal , oral and IV route Novel technologies like magnetic microspheres, immunomicrospheres offer great advantages and uses than conventional technologies. 31
- 32. Further more in future by combining various other strategies, microspheres will find the central place in novel drug delivery, particularly in diseased cellsorting ,diagnostics, gene and genetic materials, safe,targated and effective invivo delivery which may have implications in gene therapy. This area of novel drug delivery has innumerable applications and there is a need for more research to be done in this area. 32
- 33. REFERENCES Controlled Drug Delivery Novel Carrier Systems., S.P.Vyas., R.K.Khar, First Edition :2002.,Reprint :2007 page no:417,453. Review: Radioactive Microspheres for Medical Applications. International journal of Pharmaceutics 282 (2004) 1- 18,Review polymer microspheres for controlled drug release. Controlled and novel drug delivery edited by N.K.Jain reprint 2007 pg.no.236-255 International Journal for Targeted& http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2811640 33
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