Tablets

Modified-released tablet is either uncoated or coated. This contains special additives or prepared by special procedure which, separately or together, is intended to modify the rate of release of the drug into the gastrointestinal tract. It prolongs the effect of drug and also reduces the frequency of administration of drug. Several drugs are available in modified release tablet such as indomethacin.

The tablet that contains active ingredient(s) of unpleasant taste may be covered with sugar to make it more palatable. This type of tablet should be administered in whole form, otherwise the patient will experience the unpleasant taste of the active ingredient.

A small tablet that is prepared for insertion under the skin by giving a small surgical cut into the skin which is stitched after the insertion of the tablet. This tablet must be sterile one. The drug used in this preparation is usually water insoluble and the tablet provides a slow and continuous release of drug over prolonged period of time ranging from 3 to 6 months or even more Contraceptive tablet is formulated as implant.

The tablet that is covered with a thin layer or film of polymeric substance which protects the drug from atmospheric conditions and mask the objectionable taste and the odor of drug.

Some drugs are destroyed by gastric juice or causes irritation to the stomach. These two factors can be overcome by coating the tablet with cellulose acetate phthalate. This polymer is insoluble in gastric contents but readily dissolves in intestinal contents. So there is delay in the disintegration of dosage form until it reaches the small intestine. Like coated tablet, enteric coated tablet should be administered in whole form Broken or crushed form of the enteric coated tablet causes destruction of the drug by gastric juice or irritation to the stomach. Enteric coated tablet is comparatively expensive.

The drug which is destroyed or inactivated within the gastrointestinal tract but can be absorbed through the mucosal tissue of the oral cavity is usually given in this formulation. The tablet is required to be placed below the tongue for the slow release of drug. But for immediate effect some medicaments are formulated in such a way to dissolve within 1 to 2 minutes. Nitroglycerin is prepared in this formulation

The tablet that dissolves completely in liquid to produce solution of definite concentration. Mouth wash, gargle, skin lotion, douche; antibiotic, certain vitamins, and aspirin are given in this formulation.

The tablet that is intended to produce continuous effect on the mucous membrane of the throat. There is no disintegrating agent. The quality of the binding agent is increased so as to produce slow dissolution. Suitable sweetening (sugar), coloring and flavoring agents must be include in this formulation. Gum is used to give strength and cohesiveness to the lozenge and facilitating slow release of the active ingredient.

The tablet that contains acid substances and carbonate or hydrogen carbonate that react rapidly in the presence of water to release carbon dioxide. Sodium bicarbonate, citric acid and tartaric acid are added to the active ingredients to make the tablet effervescent. This preparation makes the tablet palatable.

The tablet which is intended to be broken and chewed in between the teeth before ingestion. Antacid and vitamin tablets are usually prepared as chewable tablets. It is given to the children who have difficulty in swallowing and to the adults who dislike swallowing.