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  1. 1. A Presentation On Microencapsulation By Mr. Ghodake Chaitanya A. Under the Supervision of Mr. N. A. Guajrathi Assistant ProfessorP.S.G.V.P.M’S COLLEGE OF PHARMACY, DEPARMENT OF PHARMACEUTICS, SHAHADA, DISTRICT- NANDURBAR MAHARASHTRA. 2011- 2012 1
  2. 2. CONTENTS• Introduction• Reasons for Microencapsulation• Release Mechanisms• Coating Materials• Coating Material Properties• Techniques to Manufacture• Application• References 2
  3. 3. Introduction Definition “Microencapsulation may be defined as the process of surrounding or enveloping one substance within another substance on a very small scale, yielding capsules ranging from less than one micron to several hundred microns in size.”• It is mean of applying thin coating to small particle of solid or droplet of liquid & dispersion.• Particle size: 50-5000 micron.• 2 phases: a) Core material b) Coating material• Also known as microcapsule, microsphere, coated granules, pellets. 3
  4. 4. Reasons For Microencapsulation For sustained or prolonged drug release. For masking taste and odor of many drugs to improve patient compliance. For converting liquid drugs in a free flowing powder. To reduce toxicity and GI irritation Incompatibility among the drugs can be prevented by microencapsulation. The drugs, which are sensitive to oxygen, moisture or light, can be stabilized by microencapsulation 4
  5. 5. Release Mechanisms1. Degradation controlled monolithic system2. Diffusion controlled monolithic system3. Diffusion controlled reservoir system4. Erosion 5
  6. 6. List of coating materialWater soluble Water insoluble Wax & lipid Enteric resinresin resinGelatin, Ethyl cellulose, Paraffin, Shellac,Gum arabic, Polyethylene, Carnauba wax, Zein,PVP, Polymethacrylate, Bees wax, Cellulose acetateCMC, Cellulose nitrate, Stearic acid, phthalate.Methyl cellulose, Silicones. Stearyl alcohol.Arabinogalactan,Polyvinylacrylate,Polyacrylic acid. 6
  7. 7. Coating Material Properties1. Stabilization of core material.2. Inert toward active ingredients.3. Controlled release under specific conditions.4. Film-forming, pliable, tasteless, stable.5. Non-hygroscopic, no high viscosity, economical.6. Soluble in an aqueous media or solvent, or melting.7. The coating can be flexible, brittle, hard, thin etc. 7
  8. 8. Techniques To Manufacture 1. Physical methods 1.1 Air-suspension coating 1.2 Coacervation Process 1.3 Pan coating 1.4 Spray–drying 2. Chemical process 2.1 Solvent Evaporation 2.2. Polymerization 8
  9. 9. 1. Physical Methods1.1Air-suspension The air suspension process offers wide variety of coating material candidates for microencapsulation. It consist of dispersing the solid particulate core material in supporting air stream and being coated with coating material (usually polymeric solution) 9
  10. 10. 1.2 Coacervation phase separation The general process consist of 3 steps under continuous agitation: 1. Formation of 3 immiscible chemical phase 2. Deposition of coating 3. Rigidization of coating. Step: 1) Three immiscible phases are as: a) Liquid manufacturing vehicle phase b) Core material phase c) Coating material phase. Coating material phase formed by utilizing following methods: A) Temperature change. B) By addition of incompatible polymer C) By non-solvent addition D) By salt addition E) Polymer-polymer interaction. 10
  11. 11. 1.3 Pan coatingSolid particle greater than 600 micronsize are generally consider for effectivecoating.It is used for preparation of controlled-release beads.Coating is applied as solution byautomized spray to desired solid corematerial in coating pan.Usually warm air is passed over thecoated material as the coating are beingapplied in the coating pan. Figure Pan coater 11
  12. 12. 1.4 Spray Drying and Spray CongealingSpray Drying:The coating solidification effected byrapid evaporating of solvent in whichcoating material is dissolved.Spray Congealing:The coating solidification is effectedby thermally congealing a moltencoating material. The removal ofsolvent is done by sorption, Figure Schematic diagram of a Spray Dryerextraction or evaporation technique. 12
  13. 13. 2.1 Solvent Evaporation Core material Dissolved Or Dispersed Coating polymer solution With Agitation Liquid Manufacturing Vehicle Phase Heating (If necessary) Evaporation of Polymer solvent Microencapsulation 13
  14. 14. 2.2 Polymerization • The method involve the reaction of monomeric unit located at the interface existing between a core material substance and continuous phase in which the core material is disperse. • The core material supporting phase is usually a liquid or gas, and therefore polymerization reaction occur at liquid-liquid, liquid-gas, solid-liquid, or solid-gas interface. • E.g. In the formation of polyamide (Nylon) polymeric reaction occurring at liquid-liquid interface existing between aliphatic diamine & dicarboxylic acid halide. 14
  15. 15. Application To improve the flow properties. e.g. Thiamine, Riboflavine To enhance the stability. e.g. Vitamins To reduce the volatility of materials. e.g. Peppermint oil, Methyl salicylate To avoid incompatibilities. e.g. Aspirin and Chloramphenicol To mask the unpeasant taste and odour. e.g. Aminophylline, castor oil To convert liquids into solids. e.g. Castor oil, Eprazinone, To reduce gastric irritation. e.g. Nitrofurantoin, Indomethacin 15
  16. 16. REFERENCE1. Leon, Lachman, Herbert A. L., Joseph, L. K; “ The Theory And Practice Of Industrial Pharmacy”, 3rd edition, 1990, Varghese Publishing House,412, 428.2. Microencapsulation encyclopedia of polymer science and technology, 2005 John Wiley & Sons, 1-3.3. Microencapsulation: a review international journal of pharmaceutical sciences review and research volume 1, issue 2, marches – April 2010.4. Jackson, L. S., Lee. K., (1991-01-01), “Microencapsulation and the food industry” (htm) Lebennsmittel-Wissenschaft Techonologie. Rerrived on 1991-02-02.5. Youan, B. C., Hussain, A., Nguyen, N.T., “AAPS Pharma Sci.”, 2003, 5(2). 16
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