PS 3 C

• tablets


  most common oral dose form, very uniform, formed by mixing powdered or granulated ingredients that are compressed into the tablet form. physically, chemically stable and elegant. usually swallowed whole or dispersed, deliver dose to the body in a predictable, consistent, and reproducible manner.
• types of tablets

  uncoated, film-coated (colour or to slide down throat), sugar-coated, gelatin-coated (taste), enteric-coated (acid resistant coat to protect the tablet from dissolving in substance), multi-layered, immediate/prompt release, sustained/extended release (slow release), controlled release (designed to release at a constant rate), delayed/targeted release (targeted to release drug in parts of the body). chewable/orodispersible, dispersible/soluble, effervescent, gastroretentive, sublingual, buccal, lozenges (hard) or pastilles (soft). have a local or systemic effect
• gastro retentive


  releases the drug in a controlled manner to a specific site of action
• conventional prompt release tablets


  most common dosage form, uncoated or coated. drug dissolves in stomach or intestine and is absorbed mostly in intestinal wall sometimes in stomach partially. travels via portal vein to liver (partially metabolised) and then released into systemic circulation
• excipients in tablets

  diluents/fillers, binders, disintegrants, glidants, lubricants, flavourings/sweeteners, granulation liquids, coatings, colourings
• granulation liquids


  used to make granules and then removed in manufacture, water, ethanol
• colourings


  improve appearance, aid identification, and protect light-sensitive drugs
• Commercial manufacture of tablets involves several steps:

  • Drug and excipients are blended into a powder
  • The blended powder is granulated and partially compacted to reduce volume and improve flow
  • Granules are dried and sieved to improve size, uniformity, and flowability
  • Granules, disintegrant, and lubricant are blended together
  • The mixture is compressed to make tablets
  • First compression is done to reduce volume and eliminate voids
  • Second compression at greater pressure consolidates the tablet and increases mechanical strength
  • In-process quality control testing is conducted, including dimensions, mass uniformity, hardness, friability (checking if it breaks apart when rubbed), and disintegration
  • Tablets are coated if required
  • Final quality control testing is performed
  • Packaging and labeling of the tablets
• tablet manufacture machine process

  dispensing, dry mixing, dry granulation (optional wet granulation, fluid bed dryer, conical dry mill) mixing with lubricant, tablet press (punches (rod) and dies (doughnut) which add shape and imprints) and tablet coater.
• example diphenhydramine HCl tablets

  screened ingredients in a 20-mesh sieve, blend in a V shaped blender for 3 minutes, add excipients individually and blend for a further 3-10 minutes each. compress powder into tablets. QC testing, packaging.
• coating of tablets

  spray painted in a rotating open bowl. warm air is added to dry them. film coated - very thin, just lasts in the throat. sugar-coated (core sealant over tablet core, sugar-coat and outer polish coat) disintegrates much slower.
• small scale compounded tablets

  blend actives and excipients, measure the required quantity of the mixture into tablet mould on a hand-operated tabletting machine, compress tablet, eject, repeat
• packaging of tablet

  bottles or blisters to protect from physical damage, moisture and light. bottles: glass (brown/amber), plastic (white), CRC (child resistant closures -instructions on cap to open) not childproof but slow down access for children less than 5 but can be hard to use for people with mobility issues (arthritis). Blisters: plastic film/al foil backing, al fil/al backing. CRC but has related issues
• prompt release oral tablets in the body

  ingestion via mouth into stomach, disintegration of tablet and dissolution of drug in acidic gastric fluid (1-3 pH), transfer via duodenum (5-6 pH) to small intestine (pH 6-7.5), absorption through intestinal wall, transfer via portal vein to liver ( semi-metabolised), circulation throughout body and therapeutic effects, elimination via liver and kidneys
• advantages of tablets

  mass-produced and relatively inexpensive. relatively stable, physically and chemically. elegant, simple to handle, administer store and transport. facilitate accurate and reproducible dosage. versatile and allow for tailoring of dose delivery. may contain two or more active ingredients. often may be split to adjust dose. often can be crushed and mixed with food. can be coated
• disadvantages of tablets

  not suitable for children and adults with swallowing difficulties. potential choking problems, dosages may not be appropriate for patients (splitting for animals), manufacturing process can change physicochemical properties of some drugs, some drugs are difficult to compress, some coatings may be incompatible with the drug, may take longer to disintegrate and release drug in stomach, absorption depends on patient physiological characterisitics