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Tablets

Tablets. Assoc. Prof. Dr. Jomjai Peerapattana Faculty of Pharmaceutical Sciences Khon Kaen University. Scope. Introduction Advantages and disadvantages of compressed tablets Types of tablets Tablet compression machine Tableting methods Direct compression. Introduction.

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Tablets

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  1. Tablets Assoc. Prof. Dr. Jomjai Peerapattana Faculty of Pharmaceutical Sciences Khon Kaen University

  2. Scope • Introduction • Advantages and disadvantages of compressed tablets • Types of tablets • Tablet compression machine • Tableting methods • Direct compression

  3. Introduction • 1843 a patent was granted to Thomas Brockedon (Englishman) for manufacturing pills and lozenges • 1874 both rotary and eccentric presses • 1885 glyceryl trinitrate tablets was in the BP • No other tablet monograph appeared until 1945 • 1980 nearly 300 monographs for tablets

  4. Advantages • Production aspect • Large scale production at lowest cost • Easiest and cheapest to package and ship • High stability • User aspect (doctor, pharmacist, patient) • Easy to handling • Lightest and most compact • Greatest dose precision & least content variability • Coating can mark unpleasant tastes & improve pt. acceptability

  5. Disadvantages • Some drugs resist compression into dense compacts • Drugs with poor wetting, slow dissolution, intermediate to large dosages may be difficult or impossible to formulate and manufacture as a tablet that provide adequate or full drug bioavailability • Bitter taste drugs, drugs with an objectionable odor, or sensitive to oxygen or moisture may require encapsulation or entrapment prior to compression or the tablets may require coating

  6. Absorption of drug form tablets

  7. Ingredients used in tablet formulations • Drugs • Fillers, diluent, bulking agent • To make a reasonably sized tablet • Binders • To bind powders together in the wet granulation process • To bind granule together during compression • Disintegrants • To promote breakup of the tablets • To promote rapid release of the drug

  8. Lubricants To reduce the friction during tablet ejection between the walls of the tablet and the walls of the die cavity Glidants Reducing friction between the particles To improve the flow properties of the granulations Antiadherants To prevent adherence of the granules to the punch faces and dies

  9. Dissolution (enhancers and retardants) • Wetting agents • Antioxidants • Preservatives • Coloring agents • Flavoring agents

  10. Essential properties of tablets • Accurate dosage of medicament, uniform in weight, appearance and diameter • Have the strength to withstand the rigors of mechanical shocks encountered in its production, packaging, shipping and dispensing • Release the medicinal agents in the body in a predictable and reproducible manner • Elegant product, acceptable size and shape • Chemical and physical stabilities

  11. Types of tablets • Route of administration • Oral tablets • Sublingual or buccal tablets • Vaginal tablets • Production process • Compressed tablets • Multiple compressed tablets • Tablet within a tablets: core and shell • Multilayer tablet

  12. Sugar coated tablets • Protect tablets from moisture • Mask odor and flavor • Elegance • Film coated tablets • Thin film coat • Soluble or insoluble polymer film

  13. Chewable tablets • Rapid disintegrate • Antacid, flatulance: rapid action • Children drug • Effervescent tablets • Dissolve in the water before drink

  14. Tablet production • Powders intended for compression into tablets must possess two essential properties • Powder fluidity • The material can be transported through the hopper into the die • To produce tablets of a consistent weight • Powder flow can be improved mechanically by the use of vibrators, incorporate the glidant

  15. Powder compressibility • The property of forming a stable, intact compact mass when pressure is applied

  16. Tableting procedure • Filling • Compression • Ejection

  17. Tablet compression machines • Hopper for holding and feeding granulation to be compressed • Dies that define the size and shape of the tablet • Punches for compressing the granulation within the dies • Cam tracks for guiding the movement of the punches • Feeding mechanisms for moving granulation from the hopper into the dies

  18. Single punch machine • The compression is applied by the upper punch • Stamping press

  19. Single Punch Machine (Tablets) Upper andLower Collar Collar locker

  20. Multi-station rotary presses • The head of the tablet machine that holds the upper punches, dies and lower punches in place rotates • As the head rotates, the punches are guided up and down by fixed cam tracks, which control the sequence of filling, compression and ejection. • The portions of the head that hold the upper and lower punches are called the upper an lower turrets

  21. The portion holding the dies is called the die table • The pull down cam (C) guides the lower punches to the bottom, allowing the dies to overfill • The punches then pass over a weight-control cam (E), which reduces the fill in the dies to the desired amount

  22. A swipe off blade (D) at the end of the feed frame removes the excess granulation and directs it around the turret and back into the front of the feed frame • The lower punches travel over the lower compression roll (F) while simultaneously the upper punches ride beneath the upper compression roll (G)

  23. The upper punches enter a fixed distance into the dies, while the lower punches are raised to squeeze and compact the granulation within the dies • After the moment of compression, the upper punches are withdrawn as they follow the upper punch raising cam (H) • The lower punches ride up the cam (I) which brings the tablets flush with or slightly above the surface of the dies

  24. The tablets strike a sweep off blade affixed to the front of the feed frame (A) and slide down a chute into a receptacle • At the same time, the lower punches re-enter the pull down cam (C) and the cycle is repeated

  25. Although tablet compressing machinery has undergone numerous mechanical modifications over the years, the compaction of materials between a pair of moving punches within a stationary die has remained unchanged • The principle modification from earlier equipment has been an increase in production rate which is regulated by • Number of tooling sets • Number of compression stations • Rotational speed of the press

  26. Special adaptations of tablet machines allow for the compression of layered tablets and coated tablets • A device that chills the compression components to allow for the compression of low-melting point substances such as waxes i.e. suppositories

  27. Tableting methods • Dry methods • Direct compression • Dry granulation • Wet methods • Wet granulation

  28. Direct compression • Tablets are compressed directly from powder blends of the active ingredient and suitable excipients • No pretreatment of the powder blends by wet or dry granulation procedures is necessary

  29. Advantages • Economy • Machine: fewer manufacturing steps and pieces of equipment • Labor: reduce labor costs • Less process vallidation • Lower consumption of power

  30. Elimination of granulation process • Heat (wet granulation) • Moisture (wet granulation) • High pressure (dry granulation) Processing without the need for moisture and heat which is inherent in most wet granulation procedures

  31. Avoidance of high compaction pressures involves in producing tablets by slugging or roll compaction • Elimination of variabilities in wet granulation processing • Binders (temp, viscous, age) • Viscosity of the granulating solution (depend on its temp), • How long it has been prepared,

  32. Rate of binder addition and kneading can affect the properties of the granules formed • The granulating solution, the type and length of mixing and the method and rate of wet and dry screening can change the density and particle size of the granules, which can have a major effect on fill weight and compaction qualities

  33. Type and rate of drying • can lead not only to critical changes in equilibrium MC but also to unblending as soluble active ingredients migrate to the surfaces of the drying granules More unit processes are incorporated in production, the chances of batch-to-batch variation are compounded

  34. Prime particle dissociation • Each primary drug particle is liberated from the tablet mass and is available for dissolution • Disintegrate rapidly to the primary particle state

  35. Uniformity of particle size • Greater stability of tablet on aging • Color • Dissolution rate Fewer chemical stability problems would be encountered as compared to those made by the wet granulation process

  36. Concerns • Excipient available from only one supplier and often cost more than filler used in granulation • Procedure conservation • Machine investments • Lack of material knowledge

  37. Physical limitation of drug • No compressibility • No flowability • Physical characteristics of materials (both drug and excipient) • Size and size distribution • Moisture • Shape and surface

  38. Flowability • Density • Lot to lot variability • Dusting problem • Coloring

  39. Direct compression fillers • Common materials that have been modified in the chemical manufacturing process to improve fluidity and compressibility

  40. Soluble fillers • Lactose • Spray dried lactose • Lactose is placed in aqueous solution, removed impurities and spray dried • Mixture of large alpha monohydrate crystals and spherical aggregates of smaller crystals • Good flowability but less compressibility • Poor dilution potential

  41. Loss compressibility upon initial compaction • Problem of browning due to contamination of 5-hydroxyfurfural which was accelerated in the presence of basic amine drugs and catalyzed by tartrate, citrate and acetate ions

  42. Fast-Flo lactose (early 1970s) • Spherical aggregates of microcrystals lactose monohydrate • Held together by a higher concentration of glass (amorphous lactose) • Much more compressible • Highly fluid • Non hygroscopic

  43. Tablets are three to four times harder than regular spray dried • Tabletose: aggromerate form of lactose • More compressible than spray dried but less compressible than Fast Flo lactose

  44. Anhydrous lactose: free flowing crystalline lactose • Produced by crystallization above 93C which produces the beta form • Pass through steam heated rollers • Good flow property, contained high amount of fines, its fluidity is less than optimal • Can be reworked

  45. At high RH anhydrous lactose will pick up moisture forming the hydrated compound  increase in the size of tablets if the excipient makes up a large portion of the total tablet weight • Excellent dissolution property

  46. Sucrose • Di-Pac: cocrystallization of 97% sucrose and 3% modified dextrin • Small sucrose crystals glued together by dextrin • Good flow properties and needs a glidant only when atmospheric moisture levels are high (>50%RH) • Excellent color stability on aging

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