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Edit Comment Close Premium member Presentation Transcript INTRODUCTION TO LIQUID CRYSTALS : INTRODUCTION TO LIQUID CRYSTALS BY PATIL AKSHAY D. (Department of Pharmaceutics) GUIDED BY Dr. K S Salunkhe (HOD of Pharmaceutics) Amrutvahini College Of Pharmacy , Sangamner 1CONTENTS: CONTENTS Introduction Types Properties of liquid crystals Methods of characterization Applications Conclusion References 2INTRODUCTION: INTRODUCTION Liquid + Crystal = LC. Characteristics of both. State of order between solid and liquid ( mesogenic state). Have long range oritentional order but not positional order. Anisotropic (crystal). Can Flow like liquid. optically birefringent due to its orientational order. LC materials may not always be in an LC phase . 3TYPES: TYPES LIQUID CRYSTALS 4ROD LIKE: ROD LIKE 1.NEMATIC Molecules in this phase are long and rod-like in shape. They are free to move in space. Structure of nematic phase can be altered in a number of ways. E.g. electric or magnetic field widely used in electro-optic display devices . 5ROD LIKE: ROD LIKE 2.SMECTIC This phase can be reached at lower temperatures than the nematic phase. Molecules align themselves in layers. (They are restricted to their plane.) More order and higher viscosity. 6COLUMNAR: COLUMNAR Characterized by its columns of molecules. Discovered in 1977 by Chandrasekhar. 7HEXAGONAL / LAMELLAR: HEXAGONAL / LAMELLAR 8 PROERTIES : PROERTIES LC having the properties of both solid as well as liquids. Also optical , dielectric , daimagnetic , elastic, viscous , electrical and thrmal conductance. 9 METHODS OF CHARACTERIZATION : METHODS OF CHARACTERIZATION 10PowerPoint Presentation: APPLICATIONS 11PowerPoint Presentation: 12 APPLICATIONS IN DRUG DELIVERY : APPLICATIONS IN DRUG DELIVERY Solubility Enhancement: Many substances are more soluble in lyotropic LC. Ex.Hydrocortisone (Topical application). Use have been limited(only upto 1%). But when blended with LC of lecithin (primary solvent) and water(conc. Went upto 4%). 13 Stability Of Drug : Stability Of Drug Pluronic F127(block co-polymer)-having high solubilising capacity. Can form LC mesophase with high viscosity Enhance the stability & SR/CR of protiens , enzyems (oxidation & hydrolysis) Can be combined with carbopol , HPMC, CMC(1-5%) Pluronic polymer - special interest to pharmaceutical industry. 14 Liquid Crystalline Drug Substances : Liquid Crystalline Drug Substances Some drug substances can form mesophases . Increase/change in temperature causes the transition ( thermotropic mesomorphism ) . Lyotropic mesomorphism occurs in the presence of a solvent , usually water. 15Liquid Crystalline Drug Substances: Liquid Crystalline Drug Substances DRUGS LC FORMS Arsphenamine Nematic Nafoxidin HCl Hexagonal, cubic, lamellar Fenoprofen Lamellar Ketoprofen Lamellar Diclofenac Lamellar Disodium cromoglycinate Nematic , hexagonal Diethylammonium flufenamate Lamellar 16Liquid Crystal Polymers (LCP): Liquid Crystal Polymers (LCP ) Both thermotropic and lyotropic LC polymers exhibit characteristic microstructure features . Anisometric monomers (rods or disks) are connected to chains in an appropriate manner. These anisometrical monomers ( mesogens ) may be part of main chain LCP or side chain LCP. A sufficient flexibility is a prerequisite for the liquid crystal formation with an increase in temperature or solvent concentration. 17LCP: LCP 18 Transdermal Patches : Transdermal Patches Requires a high permeability through the stratum corneum . Control element is a membrane or a matrix. Disadvantage of so called dose-dumping. Since liquid crystalline vehicles with lamellar microstructure have high solubilization capacities , they are recommended as reservoirs for transdermal patches. 19 Sustained/Controlled Drug Release from Formulations : Sustained/Controlled Drug Release from Formulations To reduce the application frequency , sustained/ controlled formulations have been developed. LC excipients are appropriate candidates ( drug diffusion is reduced by a factor of 10 to 1000 in comparison with a liquid vehicle such as a solution) 20 Liquid Crystals in Cosmetics : Liquid Crystals in Cosmetics LC are mainly used for decorative purposes in cosmetics. Ex. Cholesteric LC (Nail varnish, eye shadow, and lipsticks) Structure of these thermotropic LC changes as a result of body temperature , resulting in the desired color effect. 21Mucosal drug delivery using cubic an hexagonal mesophases: Mucosal drug delivery using cubic an hexagonal mesophases The structure-forming materials (such as GMO, PT, OG and PG ) all possess not less than two hydroxyl groups. Which make them available for hydrogen bonding to mucus membranes, and therefore the cubic and hexagonal mesophases are good candidates for mucosal drug delivery. 22CONCLUSION: CONCLUSION The future of the LC has just began. There are still unsolved physical problems in this area. The need of LC in pharmaceutical field are more important. In pharmaceutical field it has no of applications and they are still growing. 23REFERENCES: REFERENCES 1.Chenyu Guo , Jun Wang, Fengliang Cao, Robert J. Lee, And Guangxi Zhai1, “ Lyotropic Liquid Crystal Systems In Drug Delivery” Drug Discovery Today Volume 15, December 2010, Page No. 1032-1040 2.Encyclopedia Of Pharmaceutical Technology , Third Eddition , Edited By James Swarbrik , Vol - 2 , Page No. 1115-1131. 3.Drug Delivery Systems,By - Mannfeed A. Hollinger & Vasant V. Ranade , second edittion CRC press, Page no. 355-356 24REFERENCE: REFERENCE 4.Remigton, The Science & Practice Of Pharmacy , 20 th Edittion Vol-1 , Page No 179-180 5. Advances In Drug Delivery,vol-1, By- Madhusudan Rao And A.V.Jithan,pharma Med Press,page No.450-460. 25PowerPoint Presentation: 26 You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.