The Ultimate Guide to Tablet Dosage Form Types: Exploring the Advantages and Disadvantages

Tablets are compressed solid unit dosage forms containing medicament with or without excipients, according to USP definitions. The Indian Pharmacopoeia defines pharmaceutical tablets as solid, flat, or biconvex dishes prepared by compressing a drug or combination of drugs, with or without diluents. Tablets are in different shapes and sizes, such as circular, flat, biconvex, etc.

Advantage:

• Simplest oral dosage form
• Easy to administered
• Cheap (not expensive)
• Greatest dose precision
• Patients appreciate their portability, ease of swallowing, and attractive design. 
• Sugar coating can mask unpleasant tastes, and there is no need to measure the dose. 
• During manufacturing, some tablets are divided into halves and quarters with lines to facilitate breakage when a fractional dose is required. 
• Light in weight (easy to transport)
• Tablets have the best-combined properties of chemical, mechanical, and microbiological stability among all oral dosage forms. 
• Sustained release product is possible by enteric coating

Disadvantage:

• Infants, children, and elderly people can not easily administered
• Not applicable for unconscious patients
• Not used in an emergency (slow action)
• Problem with compression to crystalline drugs.
• Drugs with poor wetting, slow dissolution properties, and optimal absorption in the GIT may be difficult to formulate or manufacture as a tablet while still providing adequate or complete drug bioavailability. 
• Encapsulation or coating may be required for drugs that are subjected to bitter testing, have an unpleasant odor, or are oxygen-sensitive. In such cases, capsules may be the most cost-effective option. 
• Some drugs resist compression into dense compacts, owing to their amorphous nature and low-density character.

Ideal properties of tablets:

• Pharmaceutical tablets should be elegant products that have the proper shape and size (appearance).
• Tablets should be free from defects like chips, cracks, discoloration, and contamination.
• Tablets should have sufficient strength to withstand mechanical shock during production, packaging, shipping, and dispensing.
• Tablets must be uniform in weight and drug content.
• Tablets must be able to release the medicament in a predictable and reproducible manner and get absorbed into the systemic circulation.
• Tablets and their medicament or excipients should be chemically and physically stable.

Classification of tablets:

A. Tablet ingested orally:

• Compressed Tablet
• Multiple compressed Tablet
• Sustained release tablet
• Enteric-coated Tablet
• Sugar coated tablet
• Film-coated Tablet
• Chewable Tablet

B. Tablet used in oral cavity

• Buccal Tablet
• Sublingual Tablet
• Troches and lozengese
• Dental care

C. Tablet administered by another route:

• Implantation tablet
• Vaginal Tablet

D. Tablet used to prepare the solution:

• Effervescent Tablet
• Dispensing tablet
• Hypodermic Tablet

A. Tablet ingested orally: 

These tablets are introduced into our body orally.

i. Compressed tablets: 

These tablets are generally prepared by compression of powdered granulation material with the help of a punching machine. No special coating. Mostly after soluble. Rapid disintegration and release of product.  e.g. Aspirin (Dispirin) paracetamol tablets (Crocin)

ii. Multiple compressed tablets: 

These are compressed into two or more layers. This process is used for those tablets that have two or more substances that are incompatible with each other. These tablets can be prepared by more than a single compression.

a. Multiple or Layered Tablet: It contains two or more layered (component)

b. Compressed coated Tablet: It contains two parts internal core (smallest Tablet) and a surrounding coat that acts as a shell.

iii. Sustained Tablet: These tablets are prepared for a long duration of action. So, these tablets release their active ingredient over a prolonged period. It is prepared by hard compression. e.g. Diclofenac SR tablets. 

iv. Enteric-coated Tablet: 

These tablets are designed to pass unchanged through the stomach and absorb into the intestine. These tables are prepared because drug substances get deactivated by gastric acid or may cause irritation in the stomach. It has delayed release properties. 

v. Sugar-coated Tablet: 

Those tablets have a sugar coating, a concentrated sugar solution. This coating is used to mask the taste and smell of drugs. It also protects the drug and enhances its appearance. 

vi. Film-coated tablets: 

They are compressed tablets coated with a thin layer of polymer, forming a skin-like film over the Tablet.

vii. Chewable Tablet: 

Those tablets are intended to be chewed by patients and easily administered to children and elderly persons who may have difficulty swallowing a tablet. Layered in size. Ex- Antacid tablets (Digiene). 

B. Tablet used in the oral cavity: 

Those tablets administered into the mouth but not swallowed are used in the oral cavity.

i. Buccal tablets: 

These tablets are placed in a buccal pouch (between gums and lips), where they dissolve or disintegrate slowly and are absorbed into the blood without passing GIT. e.g., Progesterone tablets.

ii. Sublingual Tablet: 

Those tablets are placed under the tongue, dissolving or disintegrating slowly and absorbing into the blood without passing GIT. e.g., tablets of nitroglycerin, isoproterenol hydrochloride, or erythritol tetranitrate. 

iii. Lozenges and troches: 

Those tablets are commonly used to treat sores or control coughing in the common cold. These tablets are intended to dissolve slowly in the oral cavity and are usually prepared by compression or candy molding.  e.g. Vicks lozenges, Strepsils. 

iv. Dental Cone: 

Small tablets are inserted into empty teeth sockets after extraction, preventing bacteria. These tablets contain excipients like lactose, sodium bicarbonate, and sodium chloride. It generally gets dissolved in 20-40 minutes.

C. Tablets administered by other routes:

i. Implantation tablet:

Those tablets are placed under the skin or inserted by minor surgery. These tablets have slow absorption and provide continuous release of drugs for months or years. These tablets must be sterile implants. These are made by heavy compression or fusion. These tablets are used for the administration of hormones, such as testosterone steroids, for contraction.

ii. Vaginal tablets: 

Those tablets which are inserted in the vaginal cavity and dissolve slowly. These tablets are used to release administered agents, antiseptics, etc, to prevent vaginal infection. These tablets are uncoated, bullet-shaped, or ovoid tablets for easy insertion.

D. Tablet used to prepare the solution:

Those tablets are first used to prepare the solution, and then these solutions are used for action.

i. Effervescent tablets:

Those tablets dissolve in water and release CO2 gas. These tablets are prepared by compressing granular effervescent salts such as sodium bicarbonate and citric or tartaric acid. The release of CO2 in water produces disintegration of tablets and has palatability. It also gives rapid action.

ii. Dispensing Tablet: 

These tablets were prepared to be mixed with a predefined volume of water to make a solution with a specific drug concentration. This is because tablets contain many highly potent APIs required to make solutions. e.g., naproxen sodium

iii. Hypodermic Tablet: 

The Tablet is composed of drugs and water-soluble ingredients. These tablets are dissolved in sterile water for injection and administered by parenteral routes. e.g., morphine sulphate