This document provides an overview of tablets, including their advantages and disadvantages, types, excipients used, manufacturing process, coating methods, and evaluation. Tablets are the most popular oral solid dosage form, comprising 70% of total medicines. They are easy to administer and stable, but some drugs are not suitable due to solubility or stability issues. Tablet types include immediate and sustained release, as well as those for oral, buccal, vaginal, and other routes of administration. Excipients like diluents, binders, and lubricants are necessary for tablet production. Granulation and compression are the main manufacturing steps. Tablet coating helps mask taste and protects the drug.

1. TABLET
Kiran C Rodge
Shivlingeshwar college of Pharmacy,
Almala, Tq-Ausa,Dist-Latur,Maharashtra

2. CONTENTS
 Introduction
 Advantages & disadvantages
 Types of tablets
 Tablet excipients
 Manufacturing process
 tablet coating
 defects in tablets
 evaluation of tablets

3. Introduction
 Tablets are compressed solid unit dosage form containing medicament or
medicaments with or without excipients usually circular in shape and may be flat or
biconvex.
 It is the most popular dosage form and 70% of the total medicines are dispensed
in the form of Tablet.

4. Advantages
1. Easy to administered.
2. Easy to dispense.
3. More stable.
4. Accuracy in dose.
5. Bitter and nauseous substance can be easily dispensed.
6. Light and compact.
7. Economical.
8. Sustained release product is possible by enteric coating. •

5. Disadvantages
1. Problem with compression to crystalline drug.
2. Hygroscopic drugs are not suitable for compressed tablets.
3. Drugs with low or poor water solubility, slow dissolution, may be difficult to
formulate.
4. Cost of production may be increase because of coating and encapsulation to remove
bitter and unpleasant taste.
5. Swallowing is difficult especially for children and ill (unconscious) patients.

6. Types of tablet
Tablets ingested orally
1. Compressed tablet
2. Multiple compressed tablets
3. Delayed release tablet
4. Sugar coated tablet
5. Film Coated
6. Chewable Tablet
7. Controlled Release
Tablets used in Oral cavity
1. Buccal tablet
2. Sublingual tablet
3. Troches or lozenges
4. Dental cone

7. Types of tablet
Tablets administered by
other route
1. Implantation tablet
2. Vaginal tablet
Tablets used to prepare solution
1. Effervescent tablet,
2. Dispensing tablet,
3. Hypodermic tablet
4. Tablet triturates

8. TABLETS INGESTED ORALLY
1. Compressed tablet
These are uncoated tablets made by compression of granules. These provides
rapid disintegration and drug release.
e.g. Paracetamol tablet.
2. Multiple compressed tablet
These tablets are prepared to separate physically or chemically incompatible
ingredients or to produce repeat action or prolonged action products. The
ingredients of formulation are compressed into a core tablet and the
incompatible substance with other excipients are compressed over the
previously compressed core tablet.

9. TABLETS INGESTED ORALLY
3. Sustained action tablet
These tablets when taken orally release the medicament in a sufficient quantity
as and when required to maintain maximum effective concentration of drug in the
blood.
4. Enteric coated tablet
These tablets are coated with the material which does not disintegrate in
stomach but passes through as it is i.e. enteric polymer
e.g.: Hydroxypropyl methyl cellulose etc. These tablets dissolve in intestine and
are site specific.

10. TABLETS INGESTED ORALLY
5. Sugar coated tablet
The compressed tablets with sugar coating are called sugar coated tablets. It is done
to mask the bitter and unpleasant taste and odour of the medicament. It enhances the
appearance and protects the drug from atmospheric effects. e.g. Multivitamin tablet
6. Film coated tablet
These are the compressed tablets having a film coating of film coating polymer
like hydroxypropyl cellulose, ethyl cellulose , HPMC. It also protects the
formulation from atmospheric effects. These are tasteless, have increase in
tablet weight and have less elegance. e.g. Metronidazole tablet.

11. TABLETS INGESTED ORALLY
7. Chewable tablet
These tablets are chewed in mouth and are broken into small pieces. Disintegration
time is reduced and rate of absorption increases. Easily administered for infants and
elderly persons.
e.g. Antacid tablet

12. ORAL CAVITY TABLETS
1. Buccal Tablets
These tablets are to be placed in Buccal pouch or between the gum & lip or cheek.
Tablet dissolve & disintegrated slowly & absorb directly.
2. Sublingual Tablet
These tablets are to be placed under the longue. They dissolve & disintegrated quickly
& absorbed directly without passing into G.I.T. Buccal and sublingual tablet should be
formulated with bland excipients, which do not stimulate salivation.

13. ORAL CAVITY TABLETS
3. Lozenge tablet & troches
These tablets are designed to exert a local effect on mouth or throat. These tablets
are usually used in treatment of sore throat or control coughing. The tablets are
usually used to such drug as anaesthetic, antiseptic and antibacterial agent, demulcent,
astringent and antitussive agent. Lozenges were earlier called pastilles..

14. ORAL CAVITY TABLETS
4. Dental cones
These are relatively minor compressed tablet meant for placing them in the empty
socket after tooth extraction. Usually, these tablets contain an antibacterial,
compound which is released slowly. Prevent the growth of bacteria. These tablets may
contain an astringent or coagulant to reduce bleeding. The base for these types is
sodium bicarbonate, sodium chloride or it may be amines acid. These cones generally
get dissolved in 20 to 40 min time.

15. TABLETS ADMINISTERED BY
OTHER ROUTE
1. Implantation tablet
These tablets are placed below the skin or inserted subcutaneously by means of a
minor surgical operation and are slowly absorbed. These must be sterile and are made
by heavy compression and fusion. e.g. Testosterone tablet.
2. Vaginal tablet
These tablets are meant to dissolve slowly in vaginal cavity. These are ovoid or pear
shaped and are used to release steroids, antibacterial and antiseptics etc to avoid
infections. e.g. Clotrimazole tablet.

16. TABLETS USED TO PREPARE
SOLUTIONS
1. Effervescent tablet
These tablets when added in water produce effervescence. So they dissolved rapidly in water
due to the chemical reaction which takes place between alkali bicarbonate and citric acid or
tartaric acid. These tablets are to be protected from atmospheric moisture during storage
(in well closed container). e.g. Disprin tablet (Aspirin).
2. Dispensing tablet
These are intended to be added to a given volume of water to produce a solution of a given
concentration. The medicaments given are silver proteinate and quaternary ammonium
compounds. These are highly toxic if taken orally and great care must be taken in packaging
and labelling. e.g. Enzyme tablet (Digiplex)

17. TABLETS USED TO PREPARE
SOLUTIONS
3. Hypodermic tablet
These are compressed tablets which are composed of one or more drugs. These
tablets are dissolved in sterile water and administered parenterally.
4. Tablet triturates
These are small cylindrical, moulded or compressed tablets which contains a potent
medicament with a diluent. On small scale hand operated whereas for bulk production
automated machines are used. e.g. Enzyme tablet (Digiplex)

18. EXCIPIENTS
IN TABLET FORMULATION

19. Excipients are the pharmacologically inert compounds which are necessary for
manufacturing of stable dosage form.
Ideal Properties of Excipients
 Non-toxic
 Commercially available
 Low Cost
 Physically, Chemically &
Pharmacologically inert
 Physically, Chemically inert
 Should not affect on
bioavailability of drug

20. 1. Diluent
The diluent is needed to increase the bulk when quantity of medicament is very
small in each tablet
 Lactose
 Sugar & alcohol
 Cellulose & its derivatives
 Inorganic Compounds

21. 2. Binding agent
These provides strength to the granules to keep the tablet intact and selection of
which depends on the type of tablet. e.g. gum tragacanth, methyl cellulose etc.
 Intramolecular & intermolecular Binding

22. 3. Disintegrating agent
To break the tablet in smaller particles when swallowed.
These acts by three ways:
Swelling,
By producing effervescence
By melting at body temperature.
The disintegrating agent is divided into two parts. One part is mixed with other
excipients before granules formation and the other is mixed with the dry granules
before compression.
e.g. Potato, maize, wheat starch etc.

23. 4. Lubricant
To reduce the interparticular friction during compression and between tablet and
die wall during ejection of tablet.
e.g. Talc & magnesium stearate
Lubrication is achieved by Two mechanism
a. Fluid Mechanism
b. Boundary Mechanism

24. 5. Granulating agents
These provides moisture to convert the fine powder into damp mass which after
passing through sieve forms granules.
e.g Starch paste, acacia, tragacanth. gelatin solution, iso propyl alcohol etc.
To improve the flow properties of granules.
e.g magnesium stearate &Talc
6. Glidants

25. 7. Adsorbing agents
These are used to adsorb volatile oil, liquid extracts and tincture etc. Prevent
sticking
e.g. Mg stearate, steraric acid etc.
All coloring agents must be approved and certified by FDA. Two forms of
colors are used in tablet preparation – FD &C and D & C dyes. These dyes
are applied as solution in the granulating agent or Lake form of these
dyes.
8. Colors,Flavors & sweetening agents

26. Granulation
Granulation is the size enlargement process in which primary powder particles are
made to adhere to form larger, multi particle entities called granules.
It is the process of collecting particles together by creating bonds between them.
Bonds are formed by Slugging (Dry Granulation) or Using a binding agent. (Wet
Granulation)

27. Why we need Granulation ?
 To avoid powder segregation.
 To enhance the flow of powder
 To produce uniform mixtures.
 To produce dust free formulations.
 To maintain content uniformity.
 To improve compaction characteristics of mix.

28. Granulation Methods

29. Granulation Methods

30. Granulation Methods

31. Mechanism of Granulation
 Adhesion and cohesion forces in the immobile liquid films between individual
primary powder particles.
 Interfacial forces in mobile liquid films within the granules
 The formation of solid bridges after solvent evaporation
 Attractive forces between solid particles
 Mechanical interlocking

32. 1. Adhesion and cohesion forces in immobile films.
If sufficient liquid is present in a powder to form a very thin and immobile
layer, there will be an effective decrease in inter-particulate distance and an
increase in contact area between the particles. The bond strength between
the particles also increased, as the van der Waals forces of attraction are
proportional to the particle diameter and inversely proportional to the square
of the distance of separation

33. 2.Interfacial forces in mobile liquid films.
During wet granulation liquid is added to the powder mix and will be distributed as
films around and between the particles. Sufficient liquid is usually added to exceed
that necessary for an immobile layer and to produce a mobile film.
There are three states of water distribution between particles as shown below
 Pendular State
 Funicular State
 Capillary State

34. Pendular State
This state usually occurs at low moisture level. In this state the particles are
held together by lens-shaped rings of liquid. These cause adhesion because of
the surface tension forces of the liquid-air interface and the hydrostatic
suction pressure in the liquid bridge.

35. Funicular State
This state represents an intermediate stage between the pendular and capillary
states. When the air start to displace from between the particles, the particles
arrange in funicular state. After the funicular state, the particle arrange
themselves in capillary state (as shown in the figure in the right side) and there
is no air between them..

36. Capillary State
This When all the air has been displaced from between the
particles the capillary state is reached, and the particles are
held by capillary suction at the liquid-air interface, which is
now only at the granule surface. Moist granule tensile
strength increases about three times between the Pendular
and the capillary state. It may appear that the state of the
powder bed is dependent upon the total moisture content of
the wetted powders, but the capillary state may also be
reached by decreasing the separation of the particles. This
state is the most desirable state in the process of
granulation.

37. 3.Formation of Solid bridge After Evaporation
Solid bridges: A solid bridge is formed by adhesives present in the liquid or by
materials which dissolve in the granulating liquid. These can be formed by
Partial melting
Hardening binders
Crystallization of dissolved substances.

38. 4. Attractive forces between solid particles
In the absence of liquids and solid bridges formed by binding agents, there are
two types of attractive force that can operate between particles in
pharmaceutical systems: •
Electrostatic forces
Van der Waals forces
These forces significantly increase when grain sizes decrease. •

39. 5. Mechanical Interlocking:
The mechanical interlocking theory of adhesion states that good adhesion
occurs only when an adhesive penetrates into the pores, holes and crevices and
other irregularities of the adhered surface of a substrate, and locks
mechanically to the substrate. The adhesive must not only wet the substrate,
but also have the right rheological properties to penetrate pores and openings in
a reasonable time.

40. Mechanisms of Granule Formation
a) Nucleation.
Granulation starts with particle-particle contact and adhesion due to liquid
bridges. A number of particles will join to form the Pendular state. Further
agitation densifies the Pendular bodies to form the capillary state, and these
bodies act as nuclei for further granule growth.
b) Transition.
Nuclei can grow in two possible ways: either single particles can be added to the
nuclei by Pendular bridges, or two or more nuclei may combine. The combined
nuclei will be reshaped by the agitation of the bed. This stage is characterized by
the presence of a large number of small granules with a fairly wide size
distribution.

41. Mechanisms of Granule Formation
c) Ball Growth
If agitation is continued, granule coalescence will continue and produce an
unusable, over-massed system, although this is dependent upon the amount of
liquid added and the properties of the material being granulated.

42. Mechanisms of Granule Formation
c) Ball Growth
Coalescence…
Two or more granules join to form a larger granule.
Breakage…
Granules break into fragments which adhere to other granules, forming a layer of
material over the surviving granule.
Layering...
When a second batch of powder mix is added to a bed of granules, the powder will
adhere to the granules, forming a layer over the surface and increasing the
granule size.

43. Mechanisms of Granule Formation
c) Ball Growth
Abrasion Transfer…
Agitation of the granule bed leads to the attrition of material from granules.
This abraded material adheres to other granules. There are four possible
mechanisms of ball growth, which are illustrated in Figure:

44. Mechanisms of Granule Formation
c) Ball Growth

45. COMPRESSION OF GRANULES INTO
TABLET
Tablet compression machine consist of:
1. Hopper for holding and feeding granulation to be compressed
2. Dies that define the size and shape of the tablet
3. Punches for compressing the granulation within the dies
4. Cam tracks for guiding the movement of the punches
5. Feeding mechanisms for moving granulation from the hopper into the die
6. Tablet ejector

46. Types of compression machine
A. Single punch machine • The compression is applied by the upper punch
making the single punch machine a “stamping press.”
B. Multi-station rotary presses

48. TABLET COATING

49. Tablet Coating
Reasons for coating:
1. To mask unpleasant taste and odour.
2. To improve the appearance of tablets.
3. To prevent the medicament from atmospheric effects.
4. To control the site of action of drugs.
5. To produce the sustained release product. •

50. Tablet Coating
Methods of tablet coating :
1. Sugar coating:
2. Film coating

51. SUGAR COATING
Steps of sugar coating of tablet:
1. Sieving :- The tablets to be coated are shaken in a suitable sieve to
remove the fine powder or broken pieces of tablets.
2. Sealing :- Sealing is done to ensure that a thin layer of water proof
material, such as, shellac or cellulose acid phthalate is deposited on the
surface of the tablets. The shellac or cellulose acid phthalate is
dissolved in alcohol or acetone & its several coats are given in coating
pan. A coating pan is made up of copper or stainless steel. The pan is
rotated with the help of an electric motor.

52. SUGAR COATING
3. Sub coating :- In sub coating several coats of sugar & other material
such as Gelatin, Acacia etc. are given to round of tablet and to help in
building up to tablet size. Several coats of concentrated syrup containing
acacia or gelatin are given. After each addition of the syrup, dusting
powder is sprinkled. The dusting powder is a mixture of starch, talc &
powdered acacia.
4. Syrup coating :- This is done to give sugar coats, opacity & colour to
tablets. Several coats of the syrup are applied. Colouring materials &
opacity agent are also added to the syrup The process of coating is
repeated until uniform coloured tablets are obtained.

53. SUGAR COATING
5. Finishing :- Three to four coats of sugar are applied in rapid
succession without dusting powder and cold air is circulated to dry each
coat. Thus forms a hard smooth coat.
6. Polishing :- Beeswax is dissolved in organic solvent and few coats of it
are given. The finished tablets are transferred to a polishing pan is
rotated at a suitable speed so the wax coated tablets are rubbed on
the canvas cloth. This gives a proper shining to the tablets. Sugar
coating is an art.

54. FILM COATING
In this tablets are coated by a single or mixture of film forming
polymers, such as Hydroxypropyl methyl cellulose, Hydroxy ethyl
methyl cellulose, methyl cellulose, carbowax, PEG 400 etc.
the polymer is dissolved in some volatile organic solvent and is
sprayed over the tablets in a rotating pan.
It is also used to make tablets waterproof before sugar coating.
Film coating may be enteric or non enteric. •

55. FILM COATING
Advantages:
 It is a less time consuming technique.
 Not much labour is required.
 It has no adverse affect on
 disintegration of tablets.
 Product cost is less.
 It protects the drug from the atmospheric changes such as light,
air and moisture.
 Coating is resistant to cracking and chipping.
 It does not increase the weight of the tablet.
 No waterproofing is required before actual film coating.

57. IPQC Test

58. Why we need IPQC?
 To detect the errors
 To minimize the human errors.
 Provides accurate, specific, and definite description of the procedure to
be employed.
 Rigidly followed.
 Should detect any abnormality immediately and at the same time indicate
the kind of action needed to correct the problem.
 To enforce the flow of manufacturing and packing operations according to
established routes and practice.

59. Official tests:
1. Size and shape and appearance of tablet.
2. Content of active ingredient.
3. Uniformity of weight/weight variation test
4. Uniformity of content
5. Disintegration.
6. Dissolution.
Unofficial tests:
1. Hardness test.
2. Friability