Tablets Notes | Pharmaceutical Tablets Notes Of Tablets

Tablets - Pharmaceutical Tablets  Notes Of Tablets

Content - 

Definition of tablet
What is Pharmaceutical Tablet
Advantage of Tablets
Disadvantage of Tablet

Types of Tablets
Manufacturing of Compressed Tablets
Excipients  used in Formulation of Tablets
Manufacturing defect in Tablets
Coating of Tablets
Evaluation of Tablets

Tablet - 

Definition of tablet 
Question 1: what is tablet?

Tablets are solid and unit dosage form, in which many drug substance, many active drug substance are compression into Tablets form.

what is pharmaceutical tablets?
A tablet is a pharmaceutical oral dosage form or solid unit dosage form. Tablets may be defined as the solid unit dosage form of medicament or medicaments with suitable excipients. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose

Advantage of Tablets -

1. Easy to be administered
2. easy to be dispensed
3. more stable dosage form 
4. maintain accuracy of dosage
5. lightest and the more compact
6. cheapest in packing and export
7. longer expiry date

Disadvantage of Tablets -

1. Difficult to swallow in case of children and unconscious patient.
2. Poor wetting drug have slow dissolution properties.
3. can not use in emergency cases.

जानियें कितने types की होतीं हैं Dosage Form (full notes of dosage Form) 

Types of Tablets -( tablets notes)

(A) Tablet ingested orally -

they are designed to be swallowed as they are except the chewable tablets.
they are categories in - types of tablet
a. Compressed Tablets
  • ex: Paracetamol
b. Multiple compressed tablets

  • Repeat action tablet They are one type of extended or modified release tablet. Usually contain two single doses of medication one for immediate and one for delayed release
c. multilayered tablets

  • Multilayer tablet consists of layers of drug with different release rate, having ability to prevent drug-excipient incompatibility. It provides multiple release kinetics profile in single delivery system of one or more drugs.
d. Sustained action tablets
  • A tablet that releases its active ingredient in specified doses at timed intervals.
e. Enteric coated tablets

  • Prevent the drug from early dissolution or disintegration by gastric acid, help the drug  to pass the gastric. 
f. Sugar coated tablets

  • sugar-coated tablet is coated with sugar to disguise the taste.
g. Film coated tablets

  • is a process in which a tablet, capsule, or pellet is covered by a thin layer of film to protect it or make it easier to swallow.
h. Chewable tablets

  • Chewable tablets are an oral dosage form intended to be chewed and then swallowed by the patient rather than swallowed whole. They should be designed to be palatable and be easily chewed and swallowed.

(B) Tablet used in oral cavity -

these are categories in - types of tablet 
a. Buccal tablets

  • buccal tablet one which dissolves when it is held between the cheek and gum, permitting direct absorption of the active ingredient through the oral mucosa
b. Sublingual tablets

  • Sublingual administration involves placing a drug under your tongue to dissolve and absorb into your blood through the tissue there
c. Lozenge tablet and troches

  • A throat lozenge (also known as a cough drop, troche, cachou, pastille or cough sweet) is a small, typically medicated tablet intended to be dissolved slowly in the mouth to temporarily stop coughs
d. Dental cones

  • These are relatively minor compressed tablets meant for placing them in the empty sockets after tooth extraction. 
  • They prevent the multiplication of bacteria in the socket following such extraction by using slow-releasing antibacterial compounds or to reduce bleeding by containing the astringent.

(C) Tablets administered by other routes

these are categories in- types of tablet 
a. Implantation tablets

  • These tablets are placed under the skin or inserted subcutaneously by means of minor surgical operation and are slowly absorbed.
  • These may be made by heavy compression but are normally made by fusion.
  • The implants must be sterile and should be packed individually in sterile condition
b. Vaginal tablets
  • Tablet contains clotrimazole, an antifungal medicine. It is used in the treatment of fungal infection of the vagina and helps in relieving symptoms of fungal infection of the vagina.

(D) Tablets used to prepare solutions

these are categories in- types of tablet 
a. Effervescent tablets

  • tablets are also a common intervention for gastric problems like heartburn, upset stomach, and acid indigestion.
b. Dispensing tablets

  • A tablet prepared by molding or by compression; used by the dispensing pharmacist to obtain certain potent substances in a convenient form for accurate compounding.
  • "a tablet that contains a clinically effective large amount of an effective drug".
c. Hypodermic tablets

  • Hypodermic tablets are soft, readily soluble tablets that were originally used by physicians in extemporaneous preparation of parenteral solutions. These tablets are dissolved in a suitable vehicle (water for injections) and administered by parenteral route.
d. Triturates

  • A tablet made by moistening the medication mixed with a powdered lactose or sucrose and then molding it into shape and allowing the liquid to evaporate. It usually disintegrates readily

जानिये कैसे करते हैं drug material का size छोटा
click on the given link 

Manufacturing of compressed tablets - 

Tableting methods • Wet methods – Wet granulation • Dry methods – Dry granulation – Direct compression

Raw materials → Weighing → Screening → Wet massing → Wet Sieving/Milling → Drying → Dry Screening → Mixing → Compression

  • The powder mass is wetted with the binding solution until the mass has the consistency of damp snow. 
  •  If the granulation is over wetted the granules will be hard, 
  • if not wetted sufficiently, the resulting granules will be too soft, breaking down during lubrication. 
  • The wet mass is forced through a suitable sieve.
  • Moist materials from wet milling steps is placed on large trays and placed in drying chambers.
  • After drying granulation, the lubricant or glidants are added as fine powder to promote flow of granules. 
  • These granules then compressed to get tablet.

Raw material → weighing → Screen → Mixing → Slugging → Milling → Screening → Mixing → Compression 
  • Compression granulation involves the compaction of the components of a tablet formulation by means of flat punch. 
  • These compact masses are called slug and the process is called slugging.  Slugs are then milled and screened to produce a granular form.

Raw material → Weighing → Screening → Mixing →Compression. 
  • This method is applicable for crystalline chemicals having good compressible characteristics and flow properties such as: Potassium salt (chlorate, chloride, bromide), Sodium chloride, Ammonium chloride, Methenamine etc.
  • Tablets are compressed directly from powder blends of the active ingredient and suitable excipients 
  • No Pre treatment of the powder blends by wet or dry granulation procedures is necessary.

Excipients used in formulation of tablets


These are the substances added in the manufacturing of tablet and perform following functions:


Diluents are fillers used to make up required bulk of the tablet when the drug dosage itself is inadequate to produce the bulk. 
Provide better tablet properties such as improved cohesion or to promote flow.

1. They must be non toxic 
2. They must be commercially available in acceptable grade. 
3. Their cost must be low 
4. They must be physiologically inert 
5. They must be physically & chemically stable by themselves & in combination with the drugs

EXAMPLES : Lactose starch  Microcrystalline cellulose Dibasic calcium phosphate dehydrate Calcium sulphate dihydrate, Mannitol,  Sorbitol, Sucrose, Dextrose


These materials are added either dry or in liquid form to form granules or to promote cohesive compacts for directly compressed tablet.

EXAMPLES: Natural gums: Acacia, tragacanth - 10-25% Conc solution, Cellulose derivatives: Methyl cellulose, Hydroxy propyl methyl cellulose, Hydroxy propyl cellulose 
adhesive properties. Natural protein: Gelatin- 10-20% solution
Glucose: 50% soln in water 
Synthetic polymer: Polyvinylpyrrolidone (PVP)- 2% conc. 


1. facilitate the breaking or disintegration of tablet when it contacts water in the GIT. 
2. draw water into the tablet resulting in swelling and cause the tablet to burst apart. 
3. help in dissolution of the drug and attainment of high drug bioavailability. 
4. They can increase in volume in the presence of water by 200 to 500%.
EXAMPLES: Starch, Starch derivatives – carboxymethyl starches, Pre-gelatinized starches (5%) bentonite, Microcrystalline, 
Cellulose derivatives- arboxymethylcellulose, polyvinylpyrrolidone


Antiadherents and Glidants: 
  • Lubricants are intended to reduce the friction during tablet ejection between the walls of the tablet and the walls of the die cavity in which the tablet was formed. 
  • Antiadherents are intended to reduce sticking or adhersion of tablet granulation or powder to the faces of the punches or to the die walls. 
  • Glidants are intended to promote flow of granules or powder material by reducing the friction between the particles.
Antiadherents: Starch, talc , magnesium stearate 
Glidants: Corn Starch, conc. Talc.
Lubricants: -Stearic acid salts – Calcium and Magnesium stearate - Stearic acid


(1) Masking of color drugs 
(2) Product Identification 
(3) Production of more elegant product Two forms of colors are used in tablet preparation


1. Used in chewable tablets or tablets intended to dissolve in mouth. 
2. Flavor oils are used and are added to tablet granulations in solvents, are dispersed on clays and other absorbents or emulsified in aqueous granulating agent. 
3.The maximum amount of oil that can be added is 0.5 -0.75%.


Used only in chewable tablets to exclude or limit the use of sugar in the tablets.
EXAMPLES: Saccharine

कैसे करते हैं किसी भी drug material का size sepration
click on in this link

Manufacturing defects in tablets

1. Capping : The upper or lower segment of the tablet separates horizontally, either partially or completely from the main body and comes off as a cap, during ejection from the tablet press, or during subsequent handling. 

Causes and Remedies of Capping 
1. Large amount of fines in the granulation 
2. Too dry or very low moisture content , Moisten the granules suitably
3. Not thoroughly dried granules. Dry the granules properly. 
4. Insufficient amount of binder or improper binder, use proper binding agent to overcome this problem

2. Picking and Sticking

a. Picking: the material picked up by the upper punch of machine from the upper surface of the tablet.

b. Sticking: the material is stick in the bottom or walls of the die.


1. Presence of moisture in granules.

2. Defect in formulation.

1. use dry granules
2. Anew set of dies.

3. Mottling: unequal distribution of color on the surface of the colored tablet.

1. Migration of dye in the granulation
2. uses of different type of coloration, excipients & Medicament.

1. Drying the granules on law temperature.

4. Weight variation: Its means during the compression of tablets they don't have uniform weight.

1, Granules are not in uniform size
2. no proper mixing of lubricants
3. variation in the speed of tablet machine 
The defect can be avoided by correcting and checking the above point

5. Hardness variation: Tablet do mot have a uniform weight. hardness depend on the weight of the material and the space between upper and lower punching.

factor affecting hardness of tablets
this problem may overcome by the settings of dies.

Coating of Tablets

types of tablet coating
Tablets are coated for the following purpose;
  1. To mask the unpleasant taste
  2. To improve the appearance
  3. To prevent the medicament from atmospheric efet
  4. To produce the sustained release product

types of tablet coating
1. Pan coating
2. Press Coating

1. Pan coating:

  • it is used for sugar coating, film coating, or enteric coating
  • the coating is done in a pan
  • made of metal
  • pan rotated by a motor
  • tablets to be coated fill in the pan
  • provide hot air
  • maintain the speed in such a way that the tablet remain separate from each other in pan
  • after coating polishing is done in polishing pan
2. Press coating:
  • The granules of coating material are prepared
  • a layer of coating material is placed on the performed tablet
  • it is done in Drycota Rotary Tablet Machine

Evaluation of Tablets-

  • Shape of tablets : Size & Shape  can be dimensionally described & controlled. The thickness of a tablet is only variables.Tablet thickness can be measured by micrometer or by other device. Tablet thickness should be controlled within a ± 5% variation of standard value

  • Appearance : The general appearance of a tablet, its visual identity and overall “elegance” is essential for consumer acceptance, for control of lot-to-lot uniformity Appearance of a tablet involved the measurements of a tablet’s:- Size, Shape, Colour, Odour, Taste, Surface texture

  • Content of active ingredients : the weight of the tablet being made is routinely measured to help ensure that a tablet contains the proper amount of drug. As per indian pharmacopoeia (IP) weight 20 tablets selected at random and determine the average weight 12

  • Uniformity of weight : 20 tablets are weighed. The average weight was determined. Then, tablets was weighed individually and for each tablet, the percentage of deviation of its weight from the average weight was determined.

  • Disintegration test for tablets :

  • factor affecting disintegration of tablets
  1. Disintegration Test (U.S.P.): • The U.S.P. device to test disintegration uses 6 glass tubes that are 3inch long; open at the top and 10 mesh screen at the bottom end.
  2. To test for disintegration time, one tablet is placed in each tube and the basket rack is positioned in a 1- L beaker of water, simulated gastric fluid or simulated intestinal fluid at 37 ± 2
  3. Move the basket containing the tablets up and down through a distance of 5-6 cm at a frequency of 28 to 32 cycles per minute.
  4. Floating of the tablets can be prevented by placing perforated plastic discs on each tablet. 
  5. According to the test the tablet must disintegrate and all particles must pass through the 10 mesh screen in the time specified.
  6. If any residue remains, it must have a soft mass. 
  7. Disintegration time: uncoated tablet: 5-30 minutes Coated tablet: 1-2 hours

  • Dissolution test for tablets :

  1. Dissolution is the process by which a solid solute enters a solution. 
  2. In the pharmaceutical industry, it may be defined as the amount of drug substance that goes into solution per unit time under standardized conditions of liquid/solid interface, temperature and solvent composition. 
  3. Dissolution is considered one of the most important quality control tests performed on pharmaceutical dosage forms. 
  4. Now it developing into a tool for predicting bioavailability, and in some cases, replacing clinical studies to determine bioequivalent. 
  5. Dissolution behavior of drugs has a significant effect on their pharmacological activity. 
  6.  In fact, a direct relationship between in vitro dissolution rate of many drugs and their bioavailability has been demonstrated. 
  7. It is generally referred to as in vitro-in vivo correlation(IVIVC) Apparatus-1 (Basket Type) 
  8. A single tablet is placed in a small wire mesh basket attached to the bottom of the shaft connected to a variable speed motor. 
  9. The basket is immersed in a dissolution medium contained in a 1000 ml flask. The flask is cylindrical with a hemispherical bottom. 
  10. The flask is maintained at 37±0.5˚ C by a constant temperature bath. 
  11.  The motor is adjusted to turn at the specified speed and sample of the fluid are withdrawn at intervals to determine the amount of drug in solutions. 

  • Friability test for tablets:  Friability  testing is a method, which is employed to determine physical strength of uncoated tablets upon exposure to mechanical shock and attrition. In simple words, friability test tells how much mechanical stress tablets are able to withstand during their manufacturing, distribution and handling by the customer. Throughout pharmaceutical industry, friability testing has become an accepted technology and the instrument used in to perform this process is called Friabilator or Friability Tester.
  • In friability test, samples are counted and weighted then tumbled in rotating drums with baffles, when the process is stopped; samples are moved out from the instrument, wiped-off dust and weighted again. The difference between the weight before and after the process is determined as Friability and should not exceed 1%, which is considered an ideal percentage. In some cases, where diameter of tablets is greater than 13mm, such tablets are tested on drums 10° tilted.

  • Friability Test Apparatus for tablets

  • Friability Tester : brings to you friability testers often called friabilators for accurate friability determination of compressed and uncoated tablets. These instruments are available with 1 or 2 drums as required. Confirming to specifications of USP, BP and EP, our friability testers offer reliable results, while providing you ease of operation through advanced designing and configuration of the machine.
  •  friability Tester offers many user-friendly features essential for fast working and accurate testing all the time; automatic pre-set count stop, audible alarms for user alert, a provision to connect dot matrix printer and digital weighing balance, in-built self validation program. The instrument is easy to use and maintain.
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