Title: Tablets - l
1Tablets - 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
3Essential 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.
4Essential 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. -
5Advantages
- - 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 - -
6Advantage (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
-
7Advantage (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
9Disadvantages
- 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
10Disadvantage (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
11Different 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
13Classification (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.
27Tablets 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.
28Implantation 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
29Vaginal 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.
30Effervescent 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 ?