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Formulation factors affecting drug absorption

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Formulation factors affecting drug absorption

  1. 1. ManipalCollegeofPharmaceuticalSciences(MCOPS) F O R M U L AT I O N FA C TO R S A F F E C T I N G D R U G A B S O R P T I O N P R E S E N T E D B Y : S H I K H A Y. S I N G H U N D E R T H E G U I D A N C E O F : D R V A M S H I K R I S H N A T D E P A R T M E N T O F P H A R M A C E U T I C S R E G I S T R A T I O N N O . 1 6 0 6 1 7 0 0 9
  2. 2. CONTENT 1. Introduction 2. Manufacturing variables 3. Pharmaceutic ingredients 4. Nature and type of dosage form 5. Conclusion 6. References ManipalCollegeofPharmaceuticalSciences(MCOPS) 2
  3. 3. INTRODUCTION • A drug injected intravascularly directly enters systemic circulation & exerts its pharmacological effects • If intended to act systemically, such drugs can exert their pharmacological actions only when they come into blood circulation from their site of application • Majority of drugs are administered extravascular only • Absorption is an important step ManipalCollegeofPharmaceuticalSciences(MCOPS) 3
  4. 4. MANUFACTURING/PROCESSING VARIABLES Variables Manufacturing processes Excipients ManipalCollegeofPharmaceuticalSciences(MCOPS) 4
  5. 5. MANUFACTURING PROCESSES ManipalCollegeofPharmaceuticalSciences(MCOPS)  Manufacturing processes that influence drug dissolution are 1. Compression force 5
  6. 6. 2. Method of Granulation ManipalCollegeofPharmaceuticalSciences(MCOPS) 6
  7. 7. PHARMACEUTIC INGREDIENTS/EXCIPIENTS  Despite their inertness & utility in the dosage form, excipients can influence absorption of drug  More number of excipients in a dosage form, the more complex it is & greater potential for absorption & bioavailability problems  Excipients are added to ensure 1. Stability 2. Uniformity 3. Functionability 4. Bioavailability 5. Acceptability ManipalCollegeofPharmaceuticalSciences(MCOPS) 7
  8. 8. 1. VEHICLE  Absrption depend to a large extent on its miscibility with biological fluids ManipalCollegeofPharmaceuticalSciences(MCOPS) 8
  9. 9.  Diluents are commonly added to tablet (and capsule) formulations if the required dose is inadequate to produce the necessary bulk  Eg of drug-diluent interaction resulting in poor bioavailability is that of tetracycline & DCP 2. DILUENTS ManipalCollegeofPharmaceuticalSciences(MCOPS) 9 Diluents Organic Inorganic
  10. 10. 3. BINDERS & GRANULATING AGENTS  Promote cohesive compacts before & after compression  Eg polymeric materials like starch, cellulose derivatives, acacia, PVP, etc 4. COLOURANTS  Very low concentration of water-soluble dye inhibitory effect on dissolution  Dye molecules get adsorbed onto the crystal faces & inhibit drug dissolution  E.g. brilliant blue retards dissolution of sulfathiazole ManipalCollegeofPharmaceuticalSciences(MCOPS) 10
  11. 11. 5. LUBRICANTS  To aid flow of granules  To reduce interparticle friction  Sticking of particles to dies & punches  Eg Hydrophobic in nature (several metallic stearates & waxes) 6. COATINGS  Deleterious effect of various coatings on drug dissolution from a tablet dosage form is enteric coat > sugar coat > nonenteric film coat  e.g. Shellac coated tablets, on prolonged storage, dissolve more slowly in the GIT ManipalCollegeofPharmaceuticalSciences(MCOPS) 11
  12. 12. 7. DISINTEGRANTS  Agents overcome cohesive strength of tablet & break them up on contact with water which is an important prerequisite to tablet dissolution  These are hydrophilic in nature eg MCC  Mechanism ManipalCollegeofPharmaceuticalSciences(MCOPS) 12
  13. 13. 8. BUFFERS  They create right atmosphere for dissolution e.g. buffered aspirin tablets  Buffer containing potassium cations inhibit the drug absorption e.g. vitamin B2 & sulphanilamide 9. SURFACTANTS  They may enhance or retard drug absorption 1. Promotion of wetting & dissolution of drugs 2. Better membrane contact of drug for absorption 3. Enhanced membrane permeability of the drug ManipalCollegeofPharmaceuticalSciences(MCOPS) 13
  14. 14. 10. SUSPENDING AGENTS/VISCOSITY IMPARTERS  Hydrophilic polymers like vegetable gums, semisynthetic gums & synthetic gums  Stabilize drug particles by reducing their rate of settling & by increasing viscosity of the medium they also affect palatability & pourability of solution dosage forms  Eg Na-CMC complex amphetamine increases drug absorption 11. CRYSTAL GROWTH INHIBITORS  Eg crystal growth inhibitors like PVP & PEG inhibit conversion of a high energy metastable polymorph into stable ManipalCollegeofPharmaceuticalSciences(MCOPS) 14
  15. 15. 12. COMPLEXING AGENTS  These agent alters stability, solubility, molecular size, partition coefficient & diffusion coefficient  Pharmacologically inert & must dissociate either at the absorption site or following absorption into the systemic circulation Complexation has been used to enhance drug absorption are: ManipalCollegeofPharmaceuticalSciences(MCOPS) 15 Enhanced dissolution through formation of a soluble complex e.g. ergotamine tartarate-caffeine complex Enhanced lipophilicity for better membrane permeability e.g. caffeine-PABA complex Enhanced membrane permeability e.g. enhanced GI absorption of heparin
  16. 16. NATURE & TYPE OF DOSAGE FORM ManipalCollegeofPharmaceuticalSciences(MCOPS) 16
  17. 17. SOLUTIONS  Solutions is most rapidly absorbed  Drug dissolution is absent  Factors influencing absorption of solution are: ManipalCollegeofPharmaceuticalSciences(MCOPS) 17
  18. 18. EMULSIONS  Superior to suspensions in administering poorly aqueous soluble lipophilic drugs  Absorption increases 3 fold over its aqueous suspension  Factors influencing drug absorption of emulsion 18 Surface area Interfacial tension Droplet size Surfactants Lipophilicity ManipalCollegeofPharmaceuticalSciences(MCOPS)
  19. 19. SUSPENSIONS  Drug dissolution which is generally rapid due to the large surface area of the particles ManipalCollegeofPharmaceuticalSciences(MCOPS) 19
  20. 20. POWDERS  Though powders are superior to tablets & capsules  They are not in use nowadays due to handling & palatability problems  Factors to be considered in the absorption of drug from powders are particle size Polymorphism wettability 20 ManipalCollegeofPharmaceuticalSciences(MCOPS)
  21. 21. CAPSULES  Powders & granules are administered in hard gelatin capsules whereas viscous fluids & oils in soft elastic shells  Factors of importance in case of hard gel- Drug particle size Density Polymorphism Intensity of packing Influence of diluents & excipients  Factors of importance in case of soft gel- Between the drug & the diluent Between drug & gelatin shell ManipalCollegeofPharmaceuticalSciences(MCOPS) 21
  22. 22. TABLETS 22 • Compressed Tablets > Film Coated Tablets > Sugar Coated Tablets > Enteric Coated Tablets > Sustained Release Products Factors to be considered in the absorption of drug from tablets are ManipalCollegeofPharmaceuticalSciences(MCOPS)
  23. 23. CONCLUSION • Absorption plays an major role to attain the desired therapeutic action with minimal side effects at the given period of time • Formulation factors influencing drug absorption helps us to focus on formulating drug with proper attainment of permeability of drugs to systemic circulation at given time ManipalCollegeofPharmaceuticalSciences(MCOPS) 23
  24. 24. REFERENCES 1. Brahmankar D.M., Jaiswal S.B., First edition, “Absorption of Drugs” Biopharmaceutics and Pharmacokinetics – A treatise, Vallabh Prakashan, Delhi 1995, page no. 27-77 2. Shargel L., Andrew B.C., Fourth edition “Physiologic factors related to drug absorption” Applied Biopharmaceutics and Pharmacokinetics, Prentice Hall International, INC., Stanford 1999, Page No. 99-128 ManipalCollegeofPharmaceuticalSciences(MCOPS) 24
  25. 25. 25 ANY QUERIES??? ManipalCollegeofPharmaceuticalSciences(MCOPS)
  26. 26. ManipalCollegeofPharmaceuticalSciences(MCOPS) 26

Notes de l'éditeur

  • The cause is formation of divalent calcium-tetracycline complex which is poorly soluble & thus, absorbable
  • Dyes have also been found to inhibit micellar solubilization effect of bile acids which may impair the absorption of hydrophobic drugs like steroids. Cationic dyes are more reactive than the anionic ones due to their greater power for adsorption on primary particles.
  • known to inhibit wettability, penetration of water into tablet and their disintegration and dissolution This is because the disintegrant gets coated with the lubricant if blended simultaneously which however can be prevented by adding the lubricant in the final stage. The best alternative is use of soluble lubricants like SLS and carbowaxes which promote drug dissolution
  • (acacia, tragacanth, etc),
  • from oily solutions, emulsions or suspensions of medicaments

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