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Tablets - l

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Pharmaceutical Technology ll Tablets - l Presented by Dr. Md. Harun Ar Rashid Head Department of Pharmacy NUB A tablet is a solid single unit dosage form ... – PowerPoint PPT presentation

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Title: Tablets - l


1
Tablets - l
Pharmaceutical Technology ll
  • Presented by
  • Dr. Md. Harun Ar Rashid
  • Head
  • Department of Pharmacy
  • NUB

2
  • A tablet is a solid single unit dosage form
    containing one or more active ingredients with or
    without auxillary substances, prepared by
    compression and molding.
  • Intended mainly for oral administration
  • Most commonly are disk shaped with convex
    surfaces
  • Available in special shape like round, oval,
    oblong, cylindrical, square, triangular
  • Widely used solid dosage form because they offer
    a number of advantages to the patient,
    prescriber, manufacturer and manufacturing
    pharmacist

3
Essential qualities of a good Tablets
  • -They should be accurate and uniform in weight
  • -The drugs should be uniformly distributed
    throughout the tablets
  • -The size and shape should be reasonable for easy
    administration
  • -The tablets should not be too hard that it may
    not disintegrate in the Stomach
  • -There should not be any incompatibilities
  • -They should be chemically and physically stable
    during storage . Cont.

4
Essential qualities of a good Tablets
  • - They should not break during transportation or
    crumble in the hands of the patient
  • - They should be attractive in appearances
  • - There should not be any manufacturing
  • defects like cracking, chipping discolouration
  • - After disintegration it should release the
    drug readily
  • - They should be easy and economical in
    production.

5
Advantages
  • - Offer greatest dose
    precision and the least content variability
  • - easy to be swallowed or administered
  • - easy to handle and carry by the patient
  • - economical, manufacturing cost are low,
    manufacturing speed is quite high
  • - most stable with respect to physical,
    chemical and microbiological attributes
  • - Bitter, unpleasant taste and nauseous odour
    of medicaments can be easily masked by
    administering in the form of coated tablet
  • -

6
Advantage (Continued)
  • - product identification is probably the
    easiest because of the variety of shapes and
    colours of tablets that are possible
  • - the lightest and the more compact of all
    dosage forms
  • - the easiest and the cheapest to pack and
    transport
  • - dont require any measurement of dose

7
Advantage (continued)
  • Can be divided into halves, quarters by drawing
    lines during manufacture to facilitate breakage
    whenever a fractional dose is required
  • Lend themselves to certain special release
    profile such as enteric or delayed release
    products
  • Attractive and elegant in appearance

8
  • In Summary Solid Dosage Forms, Most Notably
    Tablets Provide Advantages

in storage, dispensing, and control
convenience of use
To the pharmacist
To the patient
of product identification, dosage accuracy and
precision, improved control and more reliable
therapy
To the physician
cheaper due to mass production and easier to
manufacture, simplicity, economy, stability, and
convenience
To the manufacturer
9
Disadvantages
  • Amorphous and Low density drugs are difficult to
    compress.
  • High doses are difficult to formulate as tablet
    dosage form.
  • Bitter tasting and objectionable odour drugs
    require special treatment like coating or
    encapsulation and increase the cost.
  • Drugs that are sensitive to oxygen or
    atmospheric moisture may also require special
    coating as well as costly packaging which may
    increase the overall cost of finished product

10
Disadvantage (Continued)
  • Drugs with poor wetting and slow dissolution
    properties are difficult to convert into tablets
    which will provide full drug bioavailability.
  • Drugs that are liquid at room temperature can not
    be formulated in tablet dosage form
  • A major disadvantage with respect to convenience
    of patients is the difficulty of swallowing
    specially by children and ill patients

11
Different Types of Tablets
  • Classified into a number of categories, based on
    their
  • -Their methods of manufacture
  • -Type of drug delivery system
  • - Formulation and Functions
  • Not all classes are entirely different but
    mostly overlap each other, such as,
  • - Chewable and Effervescent tablets are
    single layered uncoated tablets

12
  • Classification (continued)
  • Table1. Classified based on the method of
    manufacture and
  • type of drug deliver system
  • (A) Tablets ingested orally
  • -- Compressed tablet, e.g. Paracetamol tablet
  • Multiple compressed tablet
  • Delayed release tablet, e.g. Enteric coated
    Bisacodyl tablet
  • Sugar coated tablet, e.g. Multivitamin tablet
  • Film coated tablet, e.g. Metronidazole tablet
  • Chewable tablet, e.g. Antacid

13
Classification (continued)
  • (B) Tablets used in oral cavity
  • Buccal tablet, e.g. Vitamin-c tablet
  • Sublingual tablet, e.g. Vicks Menthol tablet
  • Troches or lozenges
  • Dental cone
  • (C) Tablets administered by other routes
  • - Implantation tablet
  • - Suppositories or Inserts, e.g. Clotrimazole
    tablet

14
(No Transcript)
15
  • (D) Tablets used to prepare solution
  • Effervescent tablet, e.g. Dispirin tablet
    (Aspirin)
  • Dispensing tablet, e.g. Enzyme tablet
    (Digiplex)
  • Hypodermic tablet
  • Tablet triturates e.g. Enzyme tablet
    (Digiplex)

16
  • Standard compressed tablet
  • - Prepared by single compression
  • - employ any of the three basic methods of
    manufactures wet granulation, dry granulation
    and direct compression.
  • - most of the tablets containing drugs intended
    to exert a local effect in the GIT are of this
    type (antacids and adsorbents)
  • - Other drugs in this group are intended to
    produce systemic effect.
  • - Tablets break up and particle deaggregation are
    important

17
  • Multiple compressed Tablet
  • Tablets of this category are usually prepared for
    one of the two reasons-
  • a. to separate physically or chemically
    incompatible ingredients
  • b. to produce repeat action or prolonged action
    products
  • - layered tablets consist of parallel layers
    obtained by
  • successive compression of particles of different
    comp.
  • - press coated or dry coated tablets are
    prepared
  • by compressing a layer of granules over a
    previously
  • compressed tablets. (manesty drycota).

18
  • The layered tablets are rapid, surface contact
    between layers is lessened, production is simpler
    so preferred.
  • The shortcomings of this category of dosage form
    for repeat action products is that its
    performance is highly dependant on gastric
    empting.
  • XX, If the second layer or core tablet quickly
    leaves the stomach following release of the
    initial fast release dose, an entirely different
    blood level profile results than if there is a
    several hour or longer delay before the second
    fraction is emptied.
  • - this is the reason that relatively few
    repeat action or controlled release products
    using this approach are marketed.

19
  • Repeat action tablets
  • In addition to compressed tablets, sugar coated
    tablet may also employed.
  • The core tablet is usually coated with shellac or
    an enteric polymer so that it will not release
    the loading drug in the stomach.
  • The second dose of drug is then added in the
    sugar coating.

20
  • Delayed action and enteric coated tablet
  • The delay action tablet dosage form is intended
    to release a drug after some time delay or after
    the tablet has passed through the part of GI
    tract into another.
  • The enteric coated tablet is the most common
    example
  • All enteric coated tablets are a type of delayed
    action tablet but not all delayed action tablet
    are enteric
  • Cellulose acetate phthalate, Polyvinyl acetate
    phthalate, Hydroxypropyl methyl cellulose phthate
    have come into use for this .
  • These polymers being acid esters, are insoluble
    in gastric media that have a pH up to about 4.

21
  • Chewable tablets
  • Are compressed tablets which have a smooth, rapid
    disintegration when chewed or allowed to dissolve
    in the mouth and contains a creamy base of a
    specially flavored and colored mannitol.
  • Two major advantages are,
  • a.The dose of most antacid is large so that the
    typical antacid tablet would be too large to
    swallow
  • b.The activity of antacid is related to its
    particle size. If the tablet is chewed prior to
    swallowing better acid neutralizing may be
    possible from a given antacid dose

22
  • Xylitol may be used in the preparation of
    sugar-free chewable tablets. Xylitol is sweeter
    than mannitol.
  • lubricant and binders must not affect the texture
    or desired hardness of the tablet
  • colorant and tart or fruity flavorants are
    commonly employed to enhance the appeal of the
    tablets
  • Examples of chewable tablets Calcium carbonate
    - antacids Erythromycin - antibiotics
    Didanosine - anti-infectives Carbamazepine -
    anticonvulsants Isosorbide dinitrate -
    vasodilator Acetaminophen - analgesics various
    vitamins and cold-allergy combination tablet

23
  • Tablets used in the oral cavity
  • This type of tablet are placed in the mouth but
    not swallowed.
  • Buccal and sublingual tablets
  • These tablets , though not swallowed, are
    intended to provide systemic drug action.
  • These are small, flat, usually oval dosage forms
    to be inserted in the buccal , or cheek, pouch
    (buccal tablet) or beneath the tongue (sublingual
    tablets).
  • The drug is absorbed directly through the oral
    mucosa, thereby avoiding the acid and enzymatic
    environment of the stomach and the drug
    metabolizing enzymes of the liver.

24
  • Drugs are commonly administered by the oral
    mucosal route
  • the vasodilator glyceryl trinitrate Steroids,
    such as methyl testosterone, testosterone
    propionate, estradiol and, possibly, some
    miscellaneous hormones and drugs, such as
    pancreatic lipotropic hormone factors,
    hesperidin, and nicotinic acid.
  • Drugs that may be absorbed via the oral mucosa
    have several possible advantages (1) Avoidance
    of the gastric environment and the decomposition
    it may produce with some steroids and hormone
    (2) a more rapid onset of drug action than occurs
    with tablets which are swallowed (3) Reduction
    of nausea, with drugs that produce this effect
    when swallowed (4) More efficient drug
    utilization (lower dose), owing to avoidance of
    inactivation by liver drug metabolising enzymes.

25
  • . Drugs absorbed from the gastrointestinal tract
    enter the mesenteric circulation which feeds
    directly into the liver via the portal vein. Drug
    absorption from the oral cavity involves drug
    diffusion into the blood and lymph canals through
    the sublingual or oral mucosa. Blood is supplied
    to this region via the external carotid artery
    and is returned via the jugular veins into the
    general circulation rather than going directly
    to the portal vein. Many steroids are either
    relatively or totally inert if ingested owing to
    inactivation by liver enzymes. This loss of
    potency can be circumvented by other modes of
    administration such as intramuscular injection,
    implantation of tablets, use of vaginal
    suppositories, or absorption through the oral
    mucosa. The latter method, in many instances, is
    preferable.
  • Since most drugs, including weakly acidic drug
    moieties, are probably absorbed primarily in the
    upper small intestine. The tablet must
    disintegrate, the drug dissolve, and the stomach
    empty at least partially before drug absorption
    begin. Therefore , a time lag of 30 minutes or
    more (corresponding to the time required for the
    drug to be dissolved and leave the stomach) is
    typical before a drug effect is exerted after
    swallowing a tablet. on the other hand , total
    drug absorption typically occurs within 30
    minutes after buccal or sublingual tablets have
    been administered and onset of action is common
    with vasodilator drugs..
  • Buccal and sublingual tablets are designed not to
    disintegrate but to dissolve slowly over a 15 to
    30 minute period. The tablet composition should
    not promote salivation, which would result in
    swallowing dissolved drug, thereby circumventing
    the purpose of the buccal or sublingual tablets.

26
  • Dental cones
  • The cones may contain an antibiotic or antiseptic
    typically in a filler of Sodium bicarbonate,
    sodium chloride, amino acid, or lactose.
  • The cones are formulated and compression so that
    a small volume of serum or fluid will cause
    disintegration and dissolution in 20 to 30
    minutes.

27
Tablets administered by other routes
  • Implantation tablets
  • This is also known as pellets, are small sterile
    tablets, cylindrical shaped and usually not over
    8 mm. in length, for subcutaneous implantation in
    man or animals to provide very prolonged drug
    effects for 3 to 6 months or longer.
  • In man, use of this dosage form is limited to
    very potent drugs which are not orally absorbed,
    notably steroids such as Desoxycorticosterone,
    testosterone, or estradiol.
  • The major advantage of the dosage form is to
    provide continuous therapy over many months
    without the need for repeated parenteral dosing.
    Over a long periods of time this form of therapy
    can be most economical. Also, it may provide the
    most even and uniform hormone therapy.

28
Implantation tablets
  • The immediate and potential disadvantage of
  • implantation therapy are
  • - the surgical technique which may be required
    for implantation
  • - the difficulty of maintaining a constant drug
    release rate as the pellet changes geometry with
    dissolution
  • - the possibility of a histopathological (tissue
    toxicity) reaction against the implanted foreign
    body
  • -the need to employ a surgical technique to
    terminate the therapy should such termination
    become necessary

29
Vaginal tablets
  • Also called inserts, are generally ovoid or pear
    shaped made by compression and intended to
    undergo dissolution and drug release in the
    vaginal cavity.
  • The tablets are usually used in the treatment of
    trichomonas vaginitis and
  • contain organic iodine (iodochlor or
    iodohydroxyquinoline compounds) or other
    antiseptics, astringents, or steroids in a
    soluble base of lactose or sodium biocarbonate.

30
Effervescent tablets
  • These tablet produce effervescence when added to
    cold water. Effervescence which is usually carbon
    dioxide is generated due to chemical reaction
    which take place between a Bicarbonate and an
    acid (citric acid and Tataric acid)
  • The effervescence causes rapid disintegration of
    the tablet and also increases the palatability ?
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