Tablets in this group are release the active ingredient in oral cavity or to provide local action in oral cavity region. The tablets under this category avoids first-pass metabolism, decomposition in gastric environment, nauseatic sensations and gives rapid onset of action.

Lozenges and Troches
The tablet that is intended to produce continuous effect on the mucous membrane of the throat. They are tablets that dissolve slowly in the mouth and so release the drug dissolved in the saliva.
The tablet is a flat faced at least about 18mm in diameter and meant to suck and dissolves in the mouth. The compressed tablet is called troches and the tablets produced by fusion or candy molding process are called lozenges.

 Lozenges

Flavours and sweeteners are added to make tablets palatable. The tablet generally contains sucrose or lactose and gelatin solution to impart smooth taste. There is no disintegrating agent. The quality of the binding agent is increased so as to produce slow dissolution. Gum is used to give strength and cohesiveness to the lozenge and facilitating slow release of the active ingredient.

Lozenges for local action in mouth/ throat are: antiseptics, antibiotics, local anesthetics demulcents, antitussive agents or astringents. To produce systemic action: multivitamin tablet.


Sublingual tablets

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.

 Sub Lingual Tablet

After the tablet is placed in the mouth below the tongue, the patient should avoid eating, drinking, smoking and possibly talking in order to keep the tablet in place. Swallowing of saliva should also be avoided since the saliva may contain dissolved drug.

Bland excipients are used to avoid salivary stimulation. Due to inconvenience in administration, this dosage form is prepared only for those API(s) for which the only satisfactory nonparenteral method is this route. For example, Glyceryl trinitrate (vasodilator) and Isoprinosine sulphate (bronchodilator).

Buccal tablets

Completeness of drug absorption is desired but fast drug absorption is not intended. The tablets are designed not to disintegrate. They are flat elliptical or capsule shaped tablets as it can be easily held between gum and cheek. It’s placed near the opening of parotid duct to provide the medium to dissolve the tablet.


Buccal Tablet

Since this tablet is to be kept for 30-60 minutes in oral cavity, care should be taken to see that all the ingredients are finely divided to avoid gritty or irritating sensation. This tablet is most often used when replacement hormonal therapy is to be administered. Antifungal drugs are preferred to be administered by this route. e.g., Miconazole – under preclinical trial – still not in market.

Dental cones

These tables are designed to be loosely packed in the empty socket remaining following a tooth extraction.

Dental Cones

Main purpose behind the use of this tablet is either to prevent multiplication of bacteria in the socket by employing a slow releasing antibacterial compound or to reduce bleeding by an astringent or coagulant containing tablet. It’s formulated to dissolve or erode slowly in presence of a small volume of serum or fluid over 20-40 minutes period.


Mouth Dissolved Tablets/ Rapidly Dissolving Tablets/Orally Disintegrating Tablet (ODT)

This tablet also called mouth-dissolving, fast-dissolving, rapid-melt, porous, orodispersible, quick dissolving. ODT designed to be dissolved on the tongue rather than swallowed whole.

These kinds of tablets are preferred when fast action or relief is desired. The ODT serves as an alternative dosage form for patients who experience dysphagia (difficulty in swallowing) or for where compliance is a known issue and therefore an easier dosage form to take ensures that medication is taken. Most commonly used drugs under this formulation are the agents active against Migraine. The tablets are designed to disintegrate as well as dissolve within one minute or some within 10 seconds of oral administration in limited quantity of saliva. They liquefy on tongue and patient swallows the liquid, without the need of water.


A number of techniques are used to prepare these tablets, including lyophilization, soft direct compression. Matrices having an API and high porosity are also being prepared using sublimation process. Urea, urethane, ammonium carbonate, ammonium bicarbonate, hexamethylene, benzoic acid, naphthalene and camphor are commonly used for sublimation processing as they they volatize rapidly. After removal by sublimation, these inert volatile substances leave the matrices with a high porosity.

Disintegrants and sugar based excipients, such as sodium starch glycolate, crosscarmellose sodium, mannitol, xylitol, dextrose, fructose, maltose and polydextrose have been incorporated in almost all the orally disintegrating dosage forms (ODDFs). Taste masking poses numerous challenges since the drug product dissolves in mouth, any taste of drug must be covered, either by flavoring technique or by micro encapsulation or nanoencapsulation.

The packaging for this tablets need a higher degree of protection due to the lower hardness and more friability of the porous nature of tablets. Keep the orally disintegrating tablet in the blister pack inside the outer foil pouch until the patient is ready to take the medicine. Make sure that operator’s hands are dry and peel open the blister to remove the tablet. Place the tablet on tongue and let it dissolve.

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