Types of Tablets in Pharmaceutics: Classification, Examples, and Uses

Pharmaceutical tablets may be defined as the solid unit dosage form of one or more medicaments with or without suitable excipients and prepared either by molding or by compression.

A tablet comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from the powder into a solid dose. The compressed tablet is the most popular dosage form in use today. About two-thirds of all drugs currently prescribed are in solid form in half and of these are as compressed tablets.

Type of Tablet

1. Uncoated tablet

A single layer or more than one layer of formulation that consists of active ingredients and excipients compressed together without any additional coat or cover

2. Coated tablet

Tablets that have additional coating layer added. Examples of coatings include gums, sugar, plasticizers and waxes.

3. Dispersible tablet

Tablets that have film coats or uncoated tablets that form a uniform dispersion when it is suspended in water.

4. Effervescent tablet

Tablets that are uncoated and are intended to dissolve and disperse when mixed with organic acid or bicarbonate to produce gaseous carbon dioxide (CO₂). The CO₂ disintegrates the tablet to produces a suspension of powdered material that is readily absorbed.

Ingredients:  active medicament+ sodium carbonate / citric acid / tartaric acid

5. Modified release tablet

Coated or uncoated tablets that are designed to release the active ingredient when the desired activity or condition is reached. Examples: enteric-coated, delay-release and prolonged release

6. Enteric coated tablet

Also called as gastro-resistant, these tablets are resistant to acidic gastric juices. They are coated with a polymer material such as Cellulose acetate phthalate, Cellulose acetate trimellitate, or acrylate polymers.

7. Prolonged release tablet

Also called as extended-release or sustained-release tablets. These tablets are formulated in such a way that the release of active ingredients is controlled over a prolonged period. Special excipients are needed to be able to produce prolonged-release tablets.

8. Soluble tablet

Tablets that are dissolved in water before being administered. These may be coated or uncoated.

9. Tablets that are for mouth use

These tablets are formulated to release active ingredients when placed in the buccal cavity or mouth area. They are used when a patient has difficulty swallowing or when fast release into the bloodstream is required. Examples are buccal and sublingual tablets, lozenges and troches.

• Buccal tablets
  • tablets placed in between the gingival (gums) and cheek area
• Sublingual tablets
  • placed underneath the tongue
• Troches & Lozenges
  • place in the side of a cheek for slow release of medicament absorbed directly into the buccal cavity- Bypass first-pass metabolism.
  • Example: Local anesthetic, Antiseptic, antibacterial agent.
• Dental Cone
  • compressed tablet placement in the cavity of the empty socket after teeth extraction.

10. Implantable tablets

Tablets that are placed in other areas of the body instead of the mouth (example, rectal or vaginal tablets).

11. Chewable tablet

These are placed into mouth & chewed & Finally swallowed. Chewable tablet has no requirement of Disintegration agents.

12. Hypodermic tablet

 Tablet is dissolved with sterile water and administered by parenteral route/injection.

Advantages of tablets

1. Ease and convenience of use
2. Bitter tasting drugs can be masked with coated tablets
3. Unstable API can be administered through coated tablets
4. Modified release of active ingredients ensures patient’s compliance and increases the therapeutic effect
5. Inexpensive form of dosage
6. Stability of API
7. Most stable with respect to physical, chemical and microbiological attributes.
8. Cheapest oral dosage form, easy to handle, use and carry out with attractive and elegant appearance.
9. Cheap, easy to swallow and production does not require and additional processing steps.
10. Low manufacturing cost as compared to other solid dosage forms and large-scale production is possible.
11. An unpleasant taste can be masked by sugar coating.
12. Packing and production is cheap and does not require more space for storage.

Disadvantages of Tablets

1. The onset of action of drugs is less compared with the direct routes such as IV.
2. Smaller and geriatric patients may find it harder to swallow tablets.
3. Drugs which are amorphous and low-density character are difficult to compress into a tablet.
4. Hygroscopic drugs are not suitable for compressed tablets.
5. Drugs with low or poor water solubility, sloe dissolution, high absorbance in GI tract may be difficult to formulate.
6. Sensitive to oxygen drugs may require special coating.

MCQs- Types of Tablets

1. What is a basic characteristic of an uncoated tablet?
   a) Has an additional film or sugar coating
   b) Contains active ingredients and excipients compressed together without a coating
   c) Dissolves only in the intestine
   d) Designed for slow release
   Answer: b) Contains active ingredients and excipients compressed together without a coating
2. Which type of tablet has an additional coating layer such as gums, sugar, or waxes?
   a) Uncoated tablet
   b) Coated tablet
   c) Chewable tablet
   d) Effervescent tablet
   Answer: b) Coated tablet
3. What is the primary feature of dispersible tablets?
   a) Dissolve in water to form a uniform dispersion
   b) Dissolve only in the stomach
   c) Require biting before swallowing
   d) Are resistant to gastric juices
   Answer: a) Dissolve in water to form a uniform dispersion
4. Which ingredients are typically used in effervescent tablets?
   a) Sugar and gelatin
   b) Active medicament + sodium carbonate/citric acid/tartaric acid
   c) Gums and waxes
   d) Cellulose acetate and acrylates
   Answer: b) Active medicament + sodium carbonate/citric acid/tartaric acid
5. What distinguishes a modified release tablet?
   a) Dissolves immediately upon ingestion
   b) Releases the active ingredient over a prolonged period or at a specific target site
   c) Only used for buccal administration
   d) Contains no coating options
   Answer: b) Releases the active ingredient over a prolonged period or at a specific target site
6. Which coating makes a tablet resistant to stomach acid?
   a) Sugar coating
   b) Film coating
   c) Enteric coating
   d) Gelatin coating
   Answer: c) Enteric coating
7. Which type of tablet provides slow and controlled release of the drug?
   a) Immediate-release tablet
   b) Effervescent tablet
   c) Prolonged-release or extended-release tablet
   d) Chewable tablet
   Answer: c) Prolonged-release or extended-release tablet
8. Which type of tablet is intended to dissolve in water before administration?
   a) Coated tablet
   b) Soluble tablet
   c) Chewable tablet
   d) Buccal tablet
   Answer: b) Soluble tablet
9. What is the primary purpose of buccal and sublingual tablets?
   a) To be chewed and swallowed
   b) To release active ingredients in the mouth for quick absorption
   c) To resist stomach acid and dissolve in the intestine
   d) To be used in rectal administration
   Answer: b) To release active ingredients in the mouth for quick absorption
10. Which tablet is compressed and placed in the cavity of the socket after teeth extraction?
    a) Buccal tablet
    b) Dental cone
    c) Implantable tablet
    d) Lozenges
    Answer: b) Dental cone
11. What characterizes chewable tablets?
    a) Must be dissolved in water before swallowing
    b) Are placed in the mouth, chewed, and then swallowed without needing disintegration agents
    c) Are only used for adult medication
    d) Need to be split into smaller parts for use
    Answer: b) Are placed in the mouth, chewed, and then swallowed without needing disintegration agents
12. Which advantage is associated with tablet dosage form?
    a) Difficult to mask unpleasant tastes
    b) Unstable API can be easily administered
    c) Low manufacturing cost and high stability of API
    d) Onset of action is faster than intravenous (IV) routes
    Answer: c) Low manufacturing cost and high stability of API
13. What is a major disadvantage of tablets?
    a) They have a very rapid onset of action
    b) Smaller and geriatric patients may find swallowing difficult
    c) They are always more expensive than liquids
    d) They are ineffective for all drugs
    Answer: b) Smaller and geriatric patients may find swallowing difficult
14. Which type of tablet is designed for use in the buccal cavity or mouth area for rapid absorption?
    a) Sublingual tablet
    b) Effervescent tablet
    c) Implantable tablet
    d) Dental cone
    Answer: a) Sublingual tablet
15. Which statement about hypodermic tablets is true?
    a) They are swallowed whole and absorbed in the GI tract
    b) They are dissolved in sterile water and administered by injection
    c) They are used only in veterinary medicine
    d) They are chewable for quick action
    Answer: b) They are dissolved in sterile water and administered by injection

/30

Frequently Asked Questions (FAQs) on Types of Tablets

1. What is a pharmaceutical tablet?
   A pharmaceutical tablet is a solid unit dosage form containing one or more medicaments with or without suitable excipients, prepared by molding or compression.
2. What distinguishes an uncoated tablet from a coated tablet?
   An uncoated tablet consists of compressed active ingredients and excipients without any coating, while a coated tablet has an additional layer such as sugar, gum, or polymers.
3. What is the function of an enteric-coated tablet?
   Enteric-coated tablets resist acidic gastric juices and dissolve in the intestine, protecting the drug and preventing stomach irritation.
4. Define effervescent tablets and state their composition.
   Effervescent tablets are uncoated tablets that dissolve with organic acid or bicarbonate to release CO₂ and produce a suspension; they contain active medicament plus sodium carbonate and citric or tartaric acid.
5. What are modified release tablets?
   Modified release tablets are designed to release active ingredients at a specific site or time, including delayed-release, prolonged-release, or enteric-coated tablets.
6. Why are buccal and sublingual tablets used?
   They are formulated to release drugs in the mouth for rapid absorption, bypassing first-pass metabolism, useful in patients who have difficulty swallowing.
7. What is the difference between chewable tablets and soluble tablets?
   Chewable tablets are meant to be chewed and swallowed without disintegration agents, while soluble tablets dissolve in water before administration.
8. What are implantable tablets?
   IDDSs are bioengineering devices surgically placed inside the patient’s tissues to avoid first-pass metabolism and reduce the systemic toxicity of the drug by eluting the therapeutic payload in the vicinity of the target tissues
9. List some advantages of tablets as a dosage form.
   Easy to use, mask unpleasant tastes by coating, stable, cost-effective, and suitable for controlled drug release.
10. What are common disadvantages of tablets?
    Slower onset than IV administration, swallowing difficulty for some patients, and challenges in compressing hygroscopic or poorly soluble drugs.
11. What role do excipients play in tablet formulation?
    Excipients aid in processing, stability, bioavailability, and mask taste or assist in modified release.
12. What is a dental cone?
    A compressed tablet placed in the socket after tooth extraction to aid healing.
13. What is a hypodermic tablet?
    A tablet dissolved in sterile water for parenteral (injection) administration.
14. Why are sugar-coated tablets preferred for bitter drugs?
    They mask the unpleasant taste and improve patient compliance.
15. What is the importance of the polymer coating in enteric tablets?
    It protects the drug from stomach acid and ensures release in the intestine.

Also Read….

Sugar Coating of tablets: Pharmaceutics

Defect of Sugar-coating tablet

Processing of Pharmaceutical Tablets