The Incredible World of Tablet

Abstract

Pharmaceutical oral drug delivery is the most commonly used route of administration compared to other route of administration. Solid dosage forms are administered orally like tablets, capsules, pills, powders, etc. Tablet is the most widely used safest oral route of administration. Tablets are solid dosage form can be made directly from powders or from granules or from film coated multiple units. Tablets are also containing drug substances with or without diluents and prepared by compression or moulding methods. Tablets can be classified as compressed tablets and moulded tablets.

Introduction

I. INTRODUCTION

Tablet is a solid unit dosage form of medicaments with suitable excipients or pharmaceutical oral solid dosage form. Tablets are occured in different size, shape, thickness, its hardness, weight , disintegration, and dissolution characteristics and depending on their intended use and method of manufacture.

A. Properties

1. Suitable for large scale production. i.e Industrial area.
2. Easy to swallow  & can be self  administered.
3. Tablet  have physical & Chemical stability to maintain its physical attributes.
4. Should be an elegant product, free from defects.
5. Size and shape of tablets influence passing of product through GIT.
6. Odour and bitter taste can be masked by coating techniques.

B. Advantages

1. They are cheapest and easiest to package and strip.
2. Lower in cost.
3. Easy to handling.
4. Lighter and compact.
5. Having greatest chemical stability over all oral dosage forms.
6. Tablet can be easily administered.
7. Easy to dispense.
8. Easy to transport in bulk.
9. Organoleptic  properties are best improved by coating of tablets.

C. Disadvantages

1. Slow onset of action  as compared to parenterals, liquid orals and capsules.
2. Poor  bioavailability of poorly soluble drugs.
3. Difficulty in swallowing in some patients like pediatrics & Unconscious patients.
4. In emergency cases, intravenous or intramuscular injections are more effective.
5. Cost of production may be increase due to coating &  encapsulation.
6. Irritant effects are occurred on GI mucosa by some solid. e.g. Aspirin

D. Ingredients

A substance  or compound that is intended to be used in the manufacture of a pharmaceutical  product as a therapeutically  active compound.  In active ingredients, tablets contains a number of inert materials also known as excipients or addditives.

Table.1 Role of ingredients

II.  MANUFACTURING METHODS

Tablets can be manufactured by three methods as follows:

A. Wet Granulation Method

It is most widely used tablet manufacturing method. This method consists some steps like weighing of ingredients, mixing , granulation, screening of damp mass, drying, lubrication and compression of tablets.This granulation method is used to improve the formulation properties like compressibility, powder flowability and for pharmaceutical manufacturing.

B. Dry Granulation Method

Dry granulation  can be conducted on a tablet press using slugging tooling or on a roller compactor. Slugging may be used to forms granules. Dry powders can be compressed using tablet machine or rotary press. Compressed slug is passed through the mesh or through the mill & remaining lubricant added to granulation and compressed to form the tablets. Ex: Paracetamol

C. Direct Compression

It involves direct compressing of powdered mixture  into the tablets. Direct compression process consists of three steps like raw material blending, tableting and coating. This method is useful for  developing particle size uniformly. Ex: Aspirin

III. TABLET COATING

Tablet coating is the process in which coating material is applied on the surface of tablet for achieving desired properties of dosage form.

A. Objectives

1. Mask the colour, odour and taste of the drug .
2. Protects the drug from gastric environment of stomach in case of acid.
3. Avoids chemical incompatibility.
4. To increase the stability.
5. For product identity.
6. Provide an elegant finish to the tablet.

B. Types of Coating

1. Sugar Coating
2. Film Coating
3. Enteric Coating
4. Press Coating
5. Specialized Coating

a. Compressed Coating

b. Electrostatic Coating

c. Dip Coating

d. Vacuum Film Coating

C. Coating Processes

1. Pan Coating
2. Fluid Bed Coating
3. Compression coating

IV. TYPES OF TABLETS

A. Oral Tablet for Ingestion

1. Standard Compressed Tablets, e.g. Paracetamol Tablets
2. Multiple Compressed Tablets, e.g. Aspirin Tablets

a. Compression Coated Tablets

b. Sugar Coated Tablets, e.g. Multivitamin Tablets

• Film Coated Tablets, e.g. Metronidazole Tablets
• Gelatin Coated Tablets, e.g. Famolate Tablet
• Enteric Coated Tablets, e.g. Besacodyl Tablets

c. Layered Tablets

d. Inlay Tablets

3. Targeted Tablets

a. Floating Tablet, e.g. Ranitidine

b. Colon Targeting Tablet, e.g. Prednisolone

4. Chewable Tablets, e.g. Antacid Tablets

5. Dispersible Tablets, e.g. Analgesic (Ibuprofen)

B. Tablets Used In Oral cavity

1. Buccal Tablets, e.g. Vit C tablets
2. Dental cones e.g. Parasorb Cone
3. Lozenges & Troches, e.g. Strepsils.
4. Sublingual Tablets, e.g. Vicks Menthol Tablets
5. Mouth Dissolved / Rapidlly Dissolving Tablets, e.g. Stemetil MD

  C. Tablets Administered By Other Routes

1. Vaginal Tablets, e.g. Clotrimazole Tablets
2. Rectal Tablets, e.g. Dulcolax.
3. Implants

D. Tablets Used To prepared Solution

1. Effervescent Tablets, e.g. Dispirin Tablets (Aspirin)
2. Molded Tablets

a. Hypodermic Tablets

b. Dispensing / Soluble Tablets, e.g.Enzyme Tablets (Digiplex)

3. Tablet Triturate, e.g. Enzyme Tablets (Digilex)

E. Structure Wise

1. Core Tablets
2. Concave Convex Tablets
3. Divisible Tablets
4. Aperture Tablets

F. Action Wise

1. Modified Release Tablet

V. EVALUATION  TESTS  FOR  TABLETS

A. Non – Official Tests

1. General Appearance: The identity of tablets and elegance  is essential for acceptance  from consumer. Control of general appearance involves measurements of tablets like size, shape, colour, odour, Taste, Surface texture.

a. Size & Shape: It can be dimensionally controlled & described. Thickness of tablet can be measured by micrometre or by other device. Standard sized of tablets are about > 5 mm in diameter. 

b. Organoleptic Properties: It involves identification of colour, odour, taste and appearance. Colour distribution should be uniform with no mottling. The colour, odour, tastes comparison compared with standard samples.

2. Hardness: Tablet crushing strength is also known as hardness of tablet. Hardness testing of tablets are useful with stand mechanical shakes  during handling, manufacturing, packing ans shipping. Tablet  hardnes defined as the force requird for breaking tablet in dimetric compression. Hardness for compressed  tablet is 5 to 8 kg.

Generally used  hardness  testers are:

a. Monsanto Tester                                

b. Strong - Cobb Tester

c. Pfizer Tester

d. Erwika Tester

e. Schleuniger Tester

3. Friability: Friability  can be defined as % of weight loss by tablets due to mechanical action (like manufacturing, packing and  transportation process) during the test. Friability tester is also known as the Roche Friabilator. It is performed for compressed  and uncoated tablets. Roche Friabilator consists a plastic chamber  which revolves 25 rpm.& dropping tablets from  height of 6 inches in friabilator chamber . This instrument is operate for 100 revolutions. For the passing this test weight of tablet needed less than 0.1 to 0.5%

B. Official Tests

1. Weight Variation: Weight variation is the quality control test which is used to confirm uniformity of dosage unit and it also support to identity, safety and quality of the product. This test is used  weighing 20 tablets individually  calculating average weight and compare individual tablet weight to the average.

       Weight variation = (IW- AW)/ AW× 100%

      Where, IW= Individual weight

                   AW= Average weight

2. Content Uniformity: It is based on assay. It is useful for determine the  amount of active ingredients by assay metods. Out of 30 tablets 10 tablets are assayed for content uniformity.

                IP: active less than 10 mg / 10%.

                BP: active less than 2 mg / 2%

               USP:active less than 25 mg / 25%

3. Dissolution: Dissolution is a process in which solid substance solubilises in a given solvent. Dissolution kinetics is important in determining the bioavailability of drug. Ex. Griseofulvin

4. Disintegration: Disintegration is the time required for the tablet to break into small particles. This test is carried out by disintegration test apparatus U.S.P device. It includes 6 glass tubes  that are 3 open at top and 10 mesh screen at bottom end. Use  6 tablets (each tablet in each tube) and the basket rack is positioned in 1-L beaker of water ,simulated gastric fluid or intestinal fluid at 37 © .Tablets remain 2.5 cm below the surface of liquid on their upword movement and not closer  than 2.5cm from the bottom of the beaker in their downword movement .Move the basket containing the tablets up and down through distance of 5-6 cm at a frequency of 28 to 32 cycles per minute.Floating of tablets can be prevented by placing perforated plastic discs on each tablet.      

References

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Copyright

Copyright © 2023 Kanchan N. Shejawal, Anuja V. Chate, Yamini A. Sonar, Prof. Akanksha A. Suryawanshi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.