Tablet, By dr. umesh kumar sharma (1)

Dr. UMESH KUMAR SHARMA,
DEPARTMENT OF PHARMACEUTICS,
MAR DIOSCORUS COLLEGE OF PHARMACY,
THIRUVANANTHAPURAM, KERALABy- Dr. Umesh Kumar Sharma

1. Introduction and definition
2. Advantages & Disadvantages
3. Types/Classification Methods:
4. Excipients,
5. Granulation methods and machinery involved,
6. Tablet compression operation
a) Single Punch
b) Rotary tablet press,
7. Manufacturing defects
8. Evaluation,
9. Packing
Contents:
By- Dr. Umesh Kumar Sharma

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 was added

Tablets are solid unit dosage form containing one or
more medicaments, with or without suitable diluents and
prepared either by moulding or compression, greatly vary
in shape, size and weight depending upon amount of
medicament used and mode of administration. They also
vary in hardness, thickness, disintegration and dissolution
characteristics. Tablets are the most widely used dosage
forms.
Tablet Definition :

Different Shapes of Tablets:

Why tablet ?
1) Powder or granules can not be taken directly due to taste or
foul smell or colour or bulkiness.
1) Spillage at the time of administration.
2) Relatively needs maximum water to swallow.
3) Special package is needed for hygroscopic drugs.
4) Certain drugs in fine state have very fast absorption.
5) Easy to carry and administer.

The advantages of the Tablet dosage form
 They are unit dosage form and offer the greatest capabilities of all oral dosage
form for the greatest dose precision and the least content variability.
 Cost is lowest of all oral dosage form.
 Lighter and compact.
 Easiest and cheapest to package and strip.
 Easy to swallowing with least tendency for hang-up.
 Sustained release product is possible by enteric coating.
 Objectionable odour and bitter taste can be masked by coating technique.
 Suitable for large scale production.
 Greatest chemical and microbial stability over all oral dosage form.
 Product identification is easy and rapid requiring no additional steps when empl
oying an embossed and/or monogrammed punch face.

The disadvantages of the Tablet dosage form
 Resistance to compression: Amorphous, low density,
 Flocculent Drugs with poor wetting, slow dissolution.
 Large dosage size.
 Bitter tasting drugs.
 Emergency / unconscious condition.
 Paediatric / geriatric use.
 Drugs with an objectionable odour.
 Drugs that are sensitive to oxygen may require
encapsulation or coating. In such cases,
capsule may offer the best and lowest cost.By- Dr. Umesh Kumar Sharma

Different Types of Tablets :
(A)Tablets ingested orally:
 Compressed tablet, eg. Paracetamol tablet
 Multiple compressed tablet, eg coldrin
 Delayed release tablet, eg. Enteric coated - Bisacodyl tablet
 Sugar coated tablet, eg. Multivitamin tablet
 Film coated tablet, eg. Metronidazole tablet
 Chewable tablet, eg. Antacid tablet
(B)Tablets used in oral cavity:
 Buccal tablet, eg. Vitamin-c tablet
 Sublingual tablet, eg trinotroglycerin,
 Troches or lozenges, eg. Vicks Menthol tablet
 Dental cone, eg. antibacterial agentsBy- Dr. Umesh Kumar Sharma

Different Types of Tablets : cont……
(C) Tablets administered by other route:
1. Implantation tablet, eg. hormones.
2. Suppositories or Inserts or pessaries, eg. Clotrimazole
tablet,
(D) Tablets used to prepare solution:
1. Effervescent tablet, e.g. Dispirin tablet (Aspirin)
2. Dispensing tablet, e.g. Enzyme tablet (Digiplex)
3. Hypodermic tablet
4. Tablet triturates, eg. Enzyme tablet (Digiplex)

Compressed tablet: These are single or multiple active
ingredients with appropriate adjuvant prepared by
compression without coating eg: paracetamol, diazepam.
Multiple compressed tablets (MCT): Prepared by subjecti
ng the fill material to more than a single compression.
1) Multiple-layered tablet,
2) Tablet-within-a-tablet
Repeat Action tablets: Multiple doses in single tablet One
dose in core-coated with enteric polymer Another dose in
coat-sugar coat.
Now a days –Outdated Uncontrolled/ unpredictable Tim
e consuming

Film-coated tablets (FCT): FCTs are compressed
tablets coated with a thin layer of polymer
capable of forming a skin-like film over the tablet.
Eg; antibiotics, antiprotozoal drugs vitamine etc.
Chewable tablets: Chewable tablets, which have a
smooth, rapid disintegration when chewed or
allowed to dissolve in the mouth.
The administration of tablets of large-size to
children and adults. Eg. nutrition supplementary d
osage form (calcium and vitamins)
Antacid.(Al, Mg hydroxide)By- Dr. Umesh Kumar Sharma

Enteric-coated tablets (ECT): Provide delayed-release
features ECTs are designed to pass unchanged through
the stomach with transit to the intestines. Scope of
application:
a. Drug substance is destroyed by gastric acid.
b. Drug substance is irritating to the gastric mucosa.
c. By-pass of the stomach enhances drug absorption.
eg; Sodium valproate etc.
Extended release or sustained tablet; These tablets
are intended to release the active ingredients over
prolonged period with predetermined rate. These
tablet avoid the dose frequency eg. Theophyllin etc.

Buccal or sublingual tablets: These are flat or oval
tablets intended to be dissolved in the buccal pouch
or beneath the tongue for absorption through the oral
mucosa (sublingual tablets). Eg Trinitroglycerin,
Scope : The drugs intended for the local effect in the
buccal cavity, the drugs those are destroyed by the
gastric juice /or are poorly absorbed from the GI tract.
Buccal tablets are designed to erode slowly, while
sublingual tablets are designed to dissolve promptly
and provide rapid drug effects.

Sugar-coated tablets (SCT): The purpose:
1) Protecting the enclosed drug from the environment.
2) Provides a barrier to objectionable taste / smelling drugs.
3) Enhances the appearance.
4) Permits the imprinting of identifying manufacturer’s infor
mation.
Disadvantages: Time, expertise, larger (50%), heavier and
more shipping cost.
Immediate release tablets: or Mouth dissolving (MD)
tablets Instantly undergoes disintegration to release the drug
(15 - 30 seconds) in the oral cavity. Mainly used for children
and geriatric patient due to swallowing problem.
Eg. vitamins, potent antibiotics etc.By- Dr. Umesh Kumar Sharma

Troches & Lozenges: Also termed as pastilles / cough dr
ops Drug incorporated in hard candy sugar base Made by co
mpression / fusion / moulding Troches- made by compressio
n Designed not to disintegrate in mouth but to dissolve Loca
l effect in mouth / throat Soar throat/ cough Contain local an
aesthetic, antiseptic, antitussive / astringents.
Dental cones: Designed to place in empty tooth socket
Antibacterial, astringent Vehicles: NaHCO3, NaCl / amino acid
Minor tablet form Designed to dissolve/ erode slowly.
Vaginal tablets: These are uncoated, bullet or ovoid shap
ed tablets which are inserted into the vagina for localized ef
fects. Eg. Antibacterials or anti-fungals, contraceptive tablets.

Tablets Implants: Designed for implantation to
provide prolonged drug effect from one month to
a year, tablets are usually small, cylindrical not
more than 8mm length. These methods require sp
ecial surgical technique for implantation and disco
ntinuation of therapy. Generally used for
administration of growth hormone and
contraceptive.
Biodegradable Implants: These are sterile in
nature. Non irritant, non toxic, biodegradable.
Eg. - Contraceptive tablets Insulin tablets.

Compressed Suppositories: The solid dosage form for rect
al use Containing non toxic, non irritant base which melt
s at body temperature These are prepared by compression.
Eg Dulcolax suppositories(laxative)
Hypodermic tablets (HT) : No longer available. HT (one
type of dispensing tablets, moulded tablets and tablet
triturates) were originally used by physicians in the
extemporaneous preparation of parenteral solutions. The
required number of tablets was dissolved in a suitable
vehicle, sterility attained and the injection performed.
Advantages: convenience, individualized
Disadvantages: the difficulty in achieving sterility

Tablet triturates (TT): Tablet triturates are small,
usually cylindrical in shape. Containing small amounts
of potent drugs.
Features:
a. Only a few tablet triturates are available today,
mostly produced by tablet compression. Few are
used sublingually, as Nitroglycerin tablets.
b. A minimal amount of pressure is applied during
their manufacture. (intended to be readily and
completely soluble in water).

a. A combination of sucrose and lactose is usually the
diluent.
b. In the past, TTs were employed in compounding pr
ocedures to provide accurate amounts of potent dr
ug substances

ADDITIVES / EXCIPIENTS

In addition to active ingredients, tablet contains a number
of inert materials known as additives or excipients.
Different excipients are:
 Diluent / fillers ● Binder
 Disintegrants, ● Lubricants and glidants,
 Colouring agents ● Flavouring agents
 Sweetening agents ● Wetting agents
 Adsorbents ● Buffers
 Antioxidants ● Chelating agents
 Dissolution enhancer ● Dissolution retardants
EXCIPIENTS:

Ideal features of an excipients include
 Non toxic & acceptable by Reg. Agencies.
 Commercially available in acceptable grade.
 Low cost and non contraindicated.
 Physiologically inert and Stable.
 Physically and chemically free from microbial load.
 No effect on bioavailability.
 Colour compatible food grade.

Diluents / Fillers:
 Used to increase the bulk volume of the drug for
making the tablet.
 This increases the size of the tablet so that it is of a size
suitable for handling.
 Fillers are only necessary if the dose of drug per tablet
is low.
Eg. : dextrose mannitol, sorbitol, Starch, sucrose,
Lactose-anhydrous and spray dried, calcium phosphates
microcrystalline cellulose (MCC) etc.

Binders:
 To ensure that granules and tablets can be formed with
the required mechanical strength.
 These materials are added either dry or in wet- form to
form granules or to form cohesive compacts .
 They hold a tablet together after it has been
compressed, preventing it from breaking during
packaging, shipping and routine handling.
Eg. : Acacia & Tragacanth (10-25%), Gelatin (10 -20 %),
Alginates, Cellulose (CMC,HPC,HPMC),
Starch Paste (10- 20%) etc.By- Dr. Umesh Kumar Sharma

Disintegrants:
 Added to a tablet formulation to facilitate its breaking
or disintegration when it contact in water in the GIT.
 Absorb water-swell-burst Helps in dissolution,
absorption and bioavailability.
 Used in two portions-Internal & External.
Eg. : Starch USP (5-20%), Modified starch 4%, Pre-gel
atinised starch (5%), bentonite (10%) etc.
Superdisintegrants: Swells up to ten fold within 30
seconds when contact water.
Eg.: Crosscarmellose, Crosspovidone,
Sod Starch Glycolate(5%) etc.By- Dr. Umesh Kumar Sharma

Glidants / Lubricants / antiadherents:
All have overlapping functions.
Glidants: Free/ smooth flow of granules.
Lubricants: Reduce friction during tablet ejection.
Antiadherents: Reduce sticking/adhesion to punch/die wall.
Eg.: Talc(5%), Cal / Mag. Stearate, starch (5-10%),
colloidal silica (0.25-3%) etc.

Colouring agent:
The colours and dyes in a tablet has three purposes:
(1) Masking of off colour drugs
(2) Product Identification
(3) Production of more elegant product.
All colouring agents must be approved and certified by
FDA. Two forms of colours are used in tablet preparation
FD&C and D & C dyes.
Eg.: FD&C yellow 6-sunset yellow, FD&C yellow 5- Tartrazine.
FD&C green 3- Fast Green, FD&C blue 1- Brilliant Blue,
FD&C blue 2 - Indigo carmine,
D&C red 3- Erythrosine etc.By- Dr. Umesh Kumar Sharma

Sweetening agents:
 For chewable tablets- Sugar, mannitol etc.
 Saccharine Sodium (artificial): 500 time’s sweeter than
sucrose Disadvantage: Bitter after taste and carcinogenic.
 Aspartame (artificial) Disadvantage: Lack of stability in
presence of moisture.
Flavoring agents:
 These are mostly used in Chewable Tablets
Eg. : Flavor oils,

Wetting agents (surfactants):
In tablet formulation surfactants aid water uptake and
thereby enhancing disintegration and assisting in drug
dissolution.
Decrease the surface tension between two liquids or
between liquid and solid, thus increase the solubility.
Anionic: Sodium lauryl sulphate (SLS) etc.
Cationic: Cetrimid etc.
Non-ionic: Tweens, Spans etc.

Adsorbents :
 Adsorbents are the agents that can retain large quantities
of liquids.
 Therefore liquids (Vitamin E, essential oils, eutectics,
hygroscopic agents) can be incorporated into tablets by
addition of adsorbents.
 Large surface- adsorbs the moisture Water- absorption
capacity:44-99%.
 Generally the liquid to be adsorbed is first mixed with
the adsorbent prior to incorporation into the formulation.
 Most commonly used adsorbents:
•anhydrous calcium phosphate, •starch, •silica etc.By- Dr. Umesh Kumar Sharma

Antioxidants :
Antioxidants are added in tablet formulation: to protect
drug from under going oxidation. Chelators may also
act as antioxidant.
Most commonly used antioxidants include.
•Ascorbic acid and their esters •Alpha-tocopherol
•Ethylene diamine •Tetra acetic acid
•Sodium metabisulfite •sodium bisulphite
•Citric acid •Tartaric acid

Chelating Agents:
Tend to form complexes with trace amount of heavy
metal ions inactivating their catalytic activity in the
oxidation of medicaments.
Most commonly used chelators:
•Ethylene diamine tetra acetic acid and its salts.
•Dihydroxy Ethyl Glycine
•Citric Acid
•Tartaric Acid.

Dissolution Enhancers:
They are the agents that alter the molecular interaction
between the ingredients to enhance the dissolution of
solute in the solvent.
Eg.: Fructose, Povidone, Surfactants etc.
Dissolution Retardants:
Dissolution retardants are incorporated in to tablet formulation
only when controlled release of drug is required.
Waxy materials like stearic acid and their esters
can be used as dissolution retardants.By- Dr. Umesh Kumar Sharma

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