P H And Ion Activated Cdds


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P H And Ion Activated Cdds

  1. 1. pH-activated and ion-activated controlled drug delivery system By SHIVA KUMAR Y Ist M. Pharmacy Dept. of Pharmaceutics K.L.E. University, Belgaum.
  2. 2. Contents… <ul><li>pH-activated CDDS </li></ul><ul><li>Ion-activated CDDS </li></ul><ul><li>references </li></ul>
  3. 3. pH-activated CDDS <ul><li>This type of DDS permits targeting the delivery of a drug only in the region with a selected pH range. </li></ul><ul><li>Intestinal pH activated DDS </li></ul><ul><li>It is fabricated by coating the drug containing core with a pH sensitive polymer combination. </li></ul><ul><li>A gastric fluid labile drug is protected by encapsulating it inside a polymer membrane that resist the degradative action of gastric pH. such as the combination of ethyl cellulose and HMC phthalate. </li></ul><ul><li>The drug is release by drug dissolution and pore channel diffusion mechanism. </li></ul>
  4. 6. Gastric pH activated DDS
  5. 7. Ion-activated CDDS <ul><li>Ionic or charged drug can be delivered by an this DDS. </li></ul><ul><li>Resins are used as the carrier for the drugs </li></ul><ul><li>Types of ion-exchange resins </li></ul><ul><li>Cation-exchangers : whose functional group can undergo reaction with cations of a surrounding solution. </li></ul><ul><li>Anion-exchangers: whose functional group can undergo reaction with anion of a surrounding solution. </li></ul>
  6. 9. Preparations of resins <ul><li>Cation exchange resin is prepared by the copolymerisation of styrene-(l) and divinyl bezene (ll). </li></ul><ul><li>Sulfonic acid group (-SO 3 - H + ) are introduced in to most of the benzene rings of the styrene-divinyl benzene polymer. </li></ul><ul><li>Anion exchange resin is prepared by first chloromethylating the benzene rings of the three dimensional styrene-divinyl benzene copolymer to attach –CH 2 Cl groups. </li></ul><ul><li>Than causing these to react with a tertiary amine, such as trimethylamine. </li></ul>
  7. 10. Drug suitable for the resinate preparation <ul><li>Drug should have acidic or basic groups in their chemical structure. </li></ul><ul><li>The biological half-life should be 2-6 hr </li></ul><ul><li>The drug is to be absorbed from all regions of the GIT. In the case of limited absorption zone, the bioavailability will be insufficient. </li></ul><ul><li>Drug should be stable sufficiently in the gastric juice. </li></ul>
  8. 11. important properties of ion-exchange resin <ul><li>Particle size </li></ul><ul><li>Porosity and swelling </li></ul><ul><li>Cross-linkage </li></ul><ul><li>stability </li></ul><ul><li>Acid base strength </li></ul>
  9. 13. Mechanism and principle
  10. 14. General preparation of drug resinates <ul><li>Purification </li></ul><ul><li>Loading of drug </li></ul><ul><li>Column process : A highly concentrated drug solution is eluted through a bed or column of the resin until equilibrium is established. </li></ul><ul><li>Batch process : The resin particles are stirred with a large volume of concentrated drug solution. </li></ul>
  11. 16. Advantages <ul><li>Ion – exchange resinates of drug can help in reducing the dose. </li></ul><ul><li>Reduced fluctuations in blood and tissue concentration level can be achieved. </li></ul><ul><li>Protection of drug form gastric enzymes. </li></ul><ul><li>Sustained or controlled release. </li></ul>
  12. 17. Limitations <ul><li>The release rate is proportional to the concentration of the ions present in the area of administration. </li></ul><ul><li>The release rate of drug can be affected by variability in diet, water intake and individual intestinal content. </li></ul>
  13. 18. References <ul><li>Novel drug delivery systems by Y. W. Chein, 2 nd edition, Dekkar series, pg. no. 195-224. </li></ul><ul><li>Controlled and novel drug delivery by N. K. Jain, C.B.S. Publishers and distributors, 1 st edition, 1997. </li></ul><ul><li>www.google.com </li></ul>
  14. 19. Thank you