Repeat action tablet: Sugar coated or multiple compressed tablets are used for this purpose.The core tablet is usually coated with shellac or an enteric polymer so that it will not release its drug in stomach but intestine.
Delayed action and enteric-coated tablet: This dosage form is intended to release the drug after some time delay or after the tablet has passed one part of the GIT into another. All enteric coated tablets are type of delayed action tablet but all delayed action tablets are not enteric or not intended to produce enteric action.
Sugar coated tablet: Primary role is to produce an elegant, glossy, easy to swallow, widely utilized in preparing multivitamin and multivitamin mineral combination. Sugar coating doubled the tablet weight. Now polymers are used with sugar solution.
Film coated tablet: One type of coated tablet in which drug is not required in coating. This is an attractive method within one or two hours. Polymers such as hydroxypropylcellulose, hydroxypropylmethyl cellulose, and colloidal dispersion of ethylcellulose are commonly used. A 30% dispersion of ethyl cellulose is known as aquacoat. Advantage of film coated over sugar coated tablets is better mechanical strength and flexibility of the coating, little increase in tablet weight.
Chewable tablet: These are intended to be chewed in the mouth before swallowing. Used for large tablet of antacid, bitter or foul testing drugs are not suitable for this type tablet.
Buccal and sublingual tablet: These tablets are small, flat and are intended to be held between the cheek and teeth or in cheek pouch (buccal tablet) or below the tongue (sublingual tablet). Drugs used by this route are for quick systematic action. The tablets are designed not to be disintegrate but slowly dissolve.
Troches and lozenges: Used in the oral cavity to exert local effect in mouth and throat. They are commonly used to treat sore throat or to control coughing in common cold. They may contain local anesthetics, antiseptic, antibacterial agents, demulcents, astringent and antitussive. The tablets are dissolving slowly over a period of 30 minutes.
Dental cone: These tablets are designed to be placed in the empty socket remaining after tooth extraction. Main purpose is to prevent microbial growth in the socket or to reduce bleeding.
Implantation tablets: Designed for substances implantation to provide prolonged drug effect from one month to a year, tablets are usually small, cylindrical not more than 8mm length. These methods require special surgical technique for implantation and discontinuation of therapy. Generally used for administration of growth hormone to food producing animal.
Vaginal tablets: These are designed to undergo slow dissolution and drug release in vaginal cavity. Tablets are wide or pear shaped, used to antibacterial, antiseptic and astringent to treat vaginal infection.
Effervescent tablets: Tablets are designed to produce a solution rapidly with the release of carbon dioxide. The tablets are prepared by compressing the active ingredient with mixture of organic acid such as citric acid or tartaric acid and sodium bicarbonate.
Dispersing tablets: Tablets are intended to be added to a given volume of water to produce a solution of a given drug concentration.
Hypodermic tablets: These tablets are composed of one or more drugs with watersoluble ingredients. Drug is added to sterile water to prepare sterile solution, which is injectable.
Tablet triturates: Usually are made from moist materials using a triturate mold, which gives them the shape of cylinder. Such tablet must be completely and rapidly soluble.
Compressed tablets: Standard uncoated tablets are manufactured by compression. The general methods are by wet granulation, dry granulation or direct compression, used for rapid disintegration and drug release. Both type of action – systemic effect and local effect.
Multiple compressed tablets: For incompatible components these are:
A) Layered tablet- either two layered (for two components) or three layered (for three components) tablet.
B) Compressed coated type- either tablet within a tablet or tablet within a tablet within a tablet.
Tablet in this category are usually prepared for two reasons
1. To separate physically or chemically incompatible ingredients.
2. To produce repeat action or prolong action product.
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