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Powders ppt

  1. 1. 1 INTRODUCTION ADVANTAGES AND DISADVANTAGES OF POWDERS DRUG POWDER FORMULATION CLASSIFICATION OF POWDERS POWDERS FOR EXTERNAL USE CONCLUSION REFERENCES
  2. 2. Introduction 2 Powders are the simplest dosage forms and the basis of many other solid dosage forms such as tablets, capsules, etc. Powders were originally designed as a convenient mode of administering hard vegetable drugs such as roots, barks and woods.
  3. 3. 3 DEFINITION: Powders are intimate mixtures of dry, finely divided drugs and/or chemicals that may be intended for internal or external use (e.g. external applications to the skin).
  4. 4. Advantages of powdersAdvantages of powders 4 Used both internally and externally. Good chemical stability compared with fluids. Rapid onset of action. Easy to swallow even in large bulk, especially if mixed with drink food. Easy to carry than the liquid dosage forms. It is suitable for small children and elderly patients. Economical.
  5. 5. 5 Disadvantages of powdersDisadvantages of powders Not suitable for drugs unstable in atmospheric conditions. Not suitable for bitter, nauseating, deliquescent and hygroscopic drugs. The dispensing of powder is a time consuming. Quantity less than 100 mg or so, cannot be weighed conveniently on dispensing balance.
  6. 6. 6 DRUG POWDER FORMULATION To obtain powder as raw material from an original drug (animal, vegetable drugs, or animal or synthetic chemical entities) by different methods of division. Mixing of various powders with or without excipients as a function of the powders’ characteristics (e.g., flow properties). Packaging of the finished product for an easy patient’s use. Formulation of powders as dosage forms is performed according to the following steps:
  7. 7. OBTENTION OF POWDERS AS RAW MATERIALS: 1.Coarse division- Reduces lump drugs into fragment of different sizes. 2.Communition- Reduces the size, gives particle size smaller than that coarse division. 7
  8. 8. 7 OBTENTION OF POWDERS AS RAW MATERIALS: Coarse division- Reduces lump drugs into fragment of different sizes. Communition- Reduces the size, gives particle size smaller than that coarse division. Methods and Equipment: 1.COARSE DIVISION 8
  9. 9. 8 Methods and Equipment: COARSE DIVISION: 2. COMMUNITION:
  10. 10. 10
  11. 11. 11 Powder Characterization: Particle size: This parameter influences the dissolution rate of the drug in- vivo, which in turn influences absorption rate and the onset of therapeutic activity. Powders with different particle sizes have different flow and packing properties, which alter the volume of powders during each event. To avoid such problems, the particle size of drugs should be defined during formulation and must be as uniform as possible.
  12. 12. 12 PARTICLE SIZE ANALYSIS  Sieving.  Microscopy.  Sedimentation Rate.  Coulter Counter.  Gas Adsorption. FLOW PROPERTIES: Flow properties of powders are important parameters in mixing and segregation phenomena, essentially during storage. Flow properties depend on particle size, nature of particles, shape and moisture content.
  13. 13. 13 Flow properties depend on particle size, nature of particles, shape and moisture content. It is determined by angle of repose, bulk or tapped density. The excipients must posses the following properties: Optimal particle size distribution, High flowability, High compressibility, Optimal capacity for a drug,
  14. 14. 14 Physiologically inert, Resistant to heat, humidity, and oxidation, Tasteless and odourless. Some of the excipients are Magnesium stearate , PEG6000, Calcium stearate , Glycerol palmito stearate ,
  15. 15. 15 MIXING OF POWDERS The aim of mixing is to obtain a homogeneous association of several solid products. Factors influencing the mixing of powders- nature of surface, density, particle size, particle shape, particle charge and proportion of materials. If these factors are not under control, segregation (demixing) can occur. Types of segregation include percolation, trajectory and densification.
  16. 16. 16 METHODS OF POWDER MIXING Spatulation (spatula + tile) Trituration (mortar + pestle) Geometric dilution: Entire quantity of potent drug (x volume) + (x volume) of the diluents + (2x volume) of the diluents + (4x volume) of the diluents……… repeated until all the diluents are used. Tumbling (wide mouth closed container)
  17. 17. 17 Packed in sifter top containers, pressurized containers, flat metal boxes. LABELLING: FOR EXTERNAL USE ONLY PACKING
  18. 18. 18 Bulk powders for external use: Bulk powders for internal use. Simple and compound powders for internal use. Powders enclosed in catchets and capsules. Compressed powders(tablets).
  19. 19. 19 Bulk powders for external use: 1.Dusting powders: They are meant for external application to the skin and generally applied in a very fine state of subdivision to avoid local irritation They are of two types : (a) Medical : They are used for superficial skin conditions, they should not be used for application to open wounds or application or broken skin. The label should clearly specify this point. We need not sterilise the ingredients of these powders but we must be sure that they are not containing pathogens.
  20. 20. 20 (b) Surgical: These powders must be sterile because they are used in body cavities and are applied on wounds. They are sprayed on burnt areas and are placed on the umbilical cords of infants. These powders usually contain an antibacterial agent. The diluent is sterilizable maize starch, which is also called as absorbable dusting powder. Function: Lubricants, protective, adsorbents, antiseptic, astringents.
  21. 21. 10 2. SNUFFS: Definition: These are finely divided solid dosage forms of medicaments inhaled into nostrils. Function: Decongestion, Antiseptic, Bronchodilator Packaging: Dispensed in flat metal boxes with hinged 21
  22. 22. 22 Dental powders are applied with the help of a tooth brush for cleaning the surface of the teeth. Dental powders contain detergents, abrasives, antiseptics and colouring and flavouring agents incorporated in a suitable base. Base is calcium carbonate. The detergent is in the form of soap and the abrasive action is provided by finely powdered pumice stone Essential oils are added to provide flavour and freshness to the mouth as well as antiseptic action. 3.DENTAL POWDERS:
  23. 23. 23 Insufflations are the medicated dusting powders introduced into body cavities such as ears, nose, throat and vagina with the help of a device called an insufflator. It sprays the powder into a stream of finely divided particles all over the site of application.
  24. 24. 24 Powder Dosage Forms are versatile, flexible in dosage strengths, relatively stable, and also convenient to manufacture, store, handle and use. It is possible to reduce them to desired particle size and thus facilitate rapid absorption. Thus from biopharmaceutical considerations POWDERS are convenient and useful for prescribing drugs.
  25. 25. 26 25 1.Jean-Mark Aiache and Erick Beyssac, Encyclopedia of Pharmaceutical Technology, 3rd Edition, volume 5, Powders as Dosage forms, pages 2971- 2982. 2.Loyd V.Allen, Jr., Nicholas G. Popovich and Howard C. Ansel , Ansel’s Pharmaceutical Dosage Forms & Drug Delivery Systems, Solid Dosage Forms, pages 186-198. 3. R M Mehta, Dispensing Pharmacy, Solid Dosage Forms, pages 108-124. C.V.S Subramanyam, J.Thimma Shetty, Sarasija Suresh and V. Kusum devi, 4. Pharmaceutical Engineering Principles and Practices, Size Reduction, Mixing, Pages 144-173,199-223
  26. 26. 27 26 5.Michael E. Aulton, Aulton’s Pharmaceutics The Design and Manufacture of Medicines, 3rd edition, Powder and Granules pages 406-409. 6. C.V.S Subrahmanyam, Textbook of Physical Pharmaceutics, 2nd edition, Micrometrics, pages 181-230.
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