logging in or signing up DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS samaju Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 444 Category: Education License: All Rights Reserved Like it (0) Dislike it (0) Added: August 09, 2011 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: rongali.pavithra (9 month(s) ago) sir please send me a copy of this Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS : DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS AJU S. SAM 1st yr. M.Pharm DEPARTMENT OF PHARMACEUTICS NEHRU COLLEGE OF PHARMACY INTRODUCTION: : INTRODUCTION: Designed to achieve a prolonged therapeutic effect. Depends on residence time in GI tract. Design embodies the approach to control drug action. Drug modification. Dosage form modification. ADVANTAGES: : ADVANTAGES: Reduced frequency of administration. Improved patient compliance. More even blood level maintained. Maximum availability with a minimum dose. Increased safety margin. Reduced ADR. Increased reliability of therapy. DISADVANTAGES: : DISADVANTAGES: Does not permit prompt termination of therapy. Immediate change in drug therapy not accommodated. Less flexibility in adjusting dosage regimen. Economic factors. DESIGN: : DESIGN: Drug modification: : Drug modification: DRUG COMPLEX : : DRUG COMPLEX : The effective release rate depends on Rate of dissolution. Rate of dissociation. Dissolution rate = Ks ˣ surface area Rate of dissolution > Rate of dissociation zero order release pattern occurs. Rate of dissociation > Rate of dissolution dissolution of complex is the rate determining step. Cont.. : Cont.. D = diffusion coefficient Cs = solubility h = thickness of diffusion layer ῤ = density W = weight of undissolved solid DRUG ADSORBATE : : DRUG ADSORBATE : Drug availability determined by Rate of dissociation (Desorption). Access of adsorbent surface to water. Effective surface area of adsorbate. PRODRUGS : : PRODRUGS : The solubility, absorption rate and elimination rate constant should be lower than parent compound. Isoniazid , Penicillin, isoproterenol. Solubility reduced and break down takes place at absorption site then availability limited by dissolution rate. Cont.. : Cont.. Preparation of drug dispersion through molecular scale drug entrapment. Suitable carrier materials act to retard release. Mechanism similar to drug adsorbates. Dosage form modification: : Dosage form modification: Allows direct incorporation of loading dose. Cont… : Cont… Principles involved in retarding drug release. Embedded matrix Drug dispersed in matrix Drug dissolved in matrix Barrier Diffusion of drug Permeation of barrier Erosion of barrier Cont.. : Cont.. Higuchi’s equation defining drug release from inert matrices. Q = [(DɛCs/T)(2A – ɛCs) t ] ½ Q – amount of drug release/ unit surface after time t. D – diffusion coefficient of drug in elution medium T - tortuosity of matrix ɛ - porosity of matrix Cs – solubility of drug in elution medium A – initial loading dose of drug in matrix Cont.. : Cont.. Barrier mediated models Formulation: : Formulation: Drug complexes. Encapsulated slow release granules. Tabletted slow release granulations. Matrix tablets. Controlled release technology. Drug complexes : : Drug complexes : Complex acids – poly galacturonic acid, arabogalactone sulphate. Bentonite + amine salts, cationic / nonionic drugs. Ion exchange resin complexes. Styrene/ divinyl benzene copolymer resins. Encapsulated slow release granules : : Encapsulated slow release granules : Pseudo latexes of ethyl cellulose modified by dibutyl sebacate & plasticized by triethyl citrate. Coating with hydrolyzed styrene maleic acid copolymer. PEG modified ethyl cellulose. Shellac, cellulose acetate phthalate. Hydrogenated oils, glyceryl stearates, fatty alcohols, microcrystalline wax. 2-10% wicking agents; greater uniform drug release Tabletted slow release granules : : Tabletted slow release granules : Tabletted mixed release granulation. Based on microdialysis cell principle. Matrix of loading dose & maintenance dose encapsulated in semi permeable coating. Matrix tablets : : Matrix tablets : Drug embedded in matrix core of retardant. Cont.. : Cont.. Loading dose are included as second layer of a two layer tablet or in a coating applied to the matrix core. Insoluble , inert - rate limiting step is liquid penetration into matrix. If wetting agent present – pore diffusion. Retardant base – carnauba wax with stearic acid or stearyl alcohol. Cont.. : Cont.. Cont... : Cont... Hydrophilic – forms gel in situ. Release controlled by penetration of water and diffusion of drug through hydrated matrix. Best matrix former – HMC 90 HG 15000,cps CONTROLLED RELEASE TECHNOLOGY : : CONTROLLED RELEASE TECHNOLOGY : CONTROLLED RELEASE SYSTEMS Dissolution controlled Diffusion & Dissolution controlled Diffusion controlled Ion-exchange resins Hydrogels Chemically controlled Water penetration controlled REFERENCES: : REFERENCES: Leon Lachman, Herbert A. Lieberman. The Theory and Practice of Industrial Pharmacy, special Indian edition; 2009: 430 – 456. Lieberman, Lachman, Schwartz. Pharmaceutical Dosage Forms: Tablets, volume III, second edition: 188- 212. Slide 26: THANK YOU You do not have the permission to view this presentation. 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DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS samaju Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 444 Category: Education License: All Rights Reserved Like it (0) Dislike it (0) Added: August 09, 2011 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: rongali.pavithra (9 month(s) ago) sir please send me a copy of this Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS : DESIGN AND FORMULATION OF SUSTAINED RELEASE TABLETS AJU S. SAM 1st yr. M.Pharm DEPARTMENT OF PHARMACEUTICS NEHRU COLLEGE OF PHARMACY INTRODUCTION: : INTRODUCTION: Designed to achieve a prolonged therapeutic effect. Depends on residence time in GI tract. Design embodies the approach to control drug action. Drug modification. Dosage form modification. ADVANTAGES: : ADVANTAGES: Reduced frequency of administration. Improved patient compliance. More even blood level maintained. Maximum availability with a minimum dose. Increased safety margin. Reduced ADR. Increased reliability of therapy. DISADVANTAGES: : DISADVANTAGES: Does not permit prompt termination of therapy. Immediate change in drug therapy not accommodated. Less flexibility in adjusting dosage regimen. Economic factors. DESIGN: : DESIGN: Drug modification: : Drug modification: DRUG COMPLEX : : DRUG COMPLEX : The effective release rate depends on Rate of dissolution. Rate of dissociation. Dissolution rate = Ks ˣ surface area Rate of dissolution > Rate of dissociation zero order release pattern occurs. Rate of dissociation > Rate of dissolution dissolution of complex is the rate determining step. Cont.. : Cont.. D = diffusion coefficient Cs = solubility h = thickness of diffusion layer ῤ = density W = weight of undissolved solid DRUG ADSORBATE : : DRUG ADSORBATE : Drug availability determined by Rate of dissociation (Desorption). Access of adsorbent surface to water. Effective surface area of adsorbate. PRODRUGS : : PRODRUGS : The solubility, absorption rate and elimination rate constant should be lower than parent compound. Isoniazid , Penicillin, isoproterenol. Solubility reduced and break down takes place at absorption site then availability limited by dissolution rate. Cont.. : Cont.. Preparation of drug dispersion through molecular scale drug entrapment. Suitable carrier materials act to retard release. Mechanism similar to drug adsorbates. Dosage form modification: : Dosage form modification: Allows direct incorporation of loading dose. Cont… : Cont… Principles involved in retarding drug release. Embedded matrix Drug dispersed in matrix Drug dissolved in matrix Barrier Diffusion of drug Permeation of barrier Erosion of barrier Cont.. : Cont.. Higuchi’s equation defining drug release from inert matrices. Q = [(DɛCs/T)(2A – ɛCs) t ] ½ Q – amount of drug release/ unit surface after time t. D – diffusion coefficient of drug in elution medium T - tortuosity of matrix ɛ - porosity of matrix Cs – solubility of drug in elution medium A – initial loading dose of drug in matrix Cont.. : Cont.. Barrier mediated models Formulation: : Formulation: Drug complexes. Encapsulated slow release granules. Tabletted slow release granulations. Matrix tablets. Controlled release technology. Drug complexes : : Drug complexes : Complex acids – poly galacturonic acid, arabogalactone sulphate. Bentonite + amine salts, cationic / nonionic drugs. Ion exchange resin complexes. Styrene/ divinyl benzene copolymer resins. Encapsulated slow release granules : : Encapsulated slow release granules : Pseudo latexes of ethyl cellulose modified by dibutyl sebacate & plasticized by triethyl citrate. Coating with hydrolyzed styrene maleic acid copolymer. PEG modified ethyl cellulose. Shellac, cellulose acetate phthalate. Hydrogenated oils, glyceryl stearates, fatty alcohols, microcrystalline wax. 2-10% wicking agents; greater uniform drug release Tabletted slow release granules : : Tabletted slow release granules : Tabletted mixed release granulation. Based on microdialysis cell principle. Matrix of loading dose & maintenance dose encapsulated in semi permeable coating. Matrix tablets : : Matrix tablets : Drug embedded in matrix core of retardant. Cont.. : Cont.. Loading dose are included as second layer of a two layer tablet or in a coating applied to the matrix core. Insoluble , inert - rate limiting step is liquid penetration into matrix. If wetting agent present – pore diffusion. Retardant base – carnauba wax with stearic acid or stearyl alcohol. Cont.. : Cont.. Cont... : Cont... Hydrophilic – forms gel in situ. Release controlled by penetration of water and diffusion of drug through hydrated matrix. Best matrix former – HMC 90 HG 15000,cps CONTROLLED RELEASE TECHNOLOGY : : CONTROLLED RELEASE TECHNOLOGY : CONTROLLED RELEASE SYSTEMS Dissolution controlled Diffusion & Dissolution controlled Diffusion controlled Ion-exchange resins Hydrogels Chemically controlled Water penetration controlled REFERENCES: : REFERENCES: Leon Lachman, Herbert A. Lieberman. The Theory and Practice of Industrial Pharmacy, special Indian edition; 2009: 430 – 456. Lieberman, Lachman, Schwartz. Pharmaceutical Dosage Forms: Tablets, volume III, second edition: 188- 212. Slide 26: THANK YOU