1. Compressed tablets- Compressed tablets are prepared

by single compression using tablet machines. It contains a number of pharmaceutical adjuncts, including diluent, binders, disintegrants, antiadherents, glidants, lubricants, or lubricating agents, and miscellaneous adjuncts. Compressed tablet is the most popular dosage form in use today. About two-thirds of all prescriptions are dispensed as solid dosage forms, and half of these are compressed tablets. A tablet can be formulated to deliver an accurate dosage to a specific site; it is usually taken orally, but can be administered sublingually, buccally, rectally or intravaginally.

2. Multiply compressed tablets

- are compressed tablets made by more than one compression cycle.

o Layered tablets are tablets prepared by compressing additional tablet granulation on a previously compressed tablet. This operation may be repeated a number of times to produce a multi-layered tablet.

o Compression-coated tablets are tablets prepared by feeding a previously compressed tablet into a special tablet machine and compressing another layer around this performed tablet. With this method a compressed tablet in which compatible ingredients may be kept in separate layers. It has all the advantages of the compressed tablet, such as: - sletting, monogramming, speed of disintegration, etc.

while retaining the attributes of the sugar-coated tablets in masking the taste of medication in the internal layers.

3. Sugar coated tablets- Sugar coated tablets are tablets

with a coating that cover up medicinal possessing objectionable tastes and odors, and protect sensitive medicinals subject to deterioration. Sugar-coated may be coated with a colored or an uncolored sugar. The process includes seal coating (waterproofing), subcoating, syrup coating (for smoothing and coloring), and polishing. Sugar-coated tablets may be 50% larger and heavier than the usual tablet.

4. Film coated- Film coated tablets has thin

layer or film of a water-soluble imparts the same general characteristics as sugar-coated tablets with the added advantage of greatly reduced time required for the coating operation. A number of polymeric substances with film-coating properties are used for this purpose.

5. Gelatin coated- Gelatin coated tablets is a

recent innovation is the gelatin-coated tablet. The innovator product, the gelcap, is a capsule-shaped compressed tablet that allows the coated product to be about one-third smaller than a capsule filled with an equivalent amount of

powder. The gelatin coating facilitates swallowing, and gelatin-coated tablets are more tamper evident than unsealed capsules.

6. Enteric coated- Enteric-coated tablets have

delayed-release features. They are designed to pass unchanged through the stomach to the intestines, where the tablets disintegrate and allow drug dissolution and absorption and/or effect. Enteric coatings are employed when the drug substance is destroyed by gastric acid or is particularly irritating to the gastric mucosa or when bypass of the stomach substantially enhances drug absorption.

7. Buccal and sublingual tablet- Buccal and sublingual tablets

are flat, oval tablets intended to be dissolved in the buccal pouch (buccal tablets) or beneath the tongue (sublingual tablets) for absorption through the oral mucosa. They enable oral absorption of drugs that are destroyed by the gastric juice and/or are poorly absorbed from the gastrointestinal tract. Buccal tablets are designed to erode slowly, whereas those for sublingual use (such as nitroglycerin) dissolve promptly and provide rapid drug effects. Lozenges or troches are disc-shaped solid dosage forms containing a medicinal agent and generally a flavoring substance in a hard candy or

sugar base. They are intended to be slowly dissolved in the oral cavity, usually for local effects, although some are formulated for systemic absorption.

8. Chewable tablets- Chewable tablets, which have a

smooth, rapid disintegration when chewed or allowed to dissolve in the mouth, have a creamy base, usually of specially flavored and colored mannitol. Chewable tablets are especially useful for administration of large tablets to children and adults who have difficulty swallowing solid dosage forms.

9. Effervescent tablet- Effervescent tablets are

prepared by compressing granular effervescent salts that release gas when in contact with water. These tablets generally contain medicinal substances that dissolve rapidly when added to water. The “bubble action” can assist in breaking up the tablets and enhancing the dissolution of the active drug.

10. Molded tablets- Molded tablets are prepared by

tablet machinery or manually by forcing dampened tablet material into a mold of any shape. The formed tablet is then ejected from the mold and allowed to dry.

11. Tablet triturates

- Tablet triturates are small, usually cylindrical, ,molded or compressed tablets containing small amounts of usually potent drugs. Today, only a few tablet triturate products are available commercially, with most of these produced by tablet compression.

12. Hypodermic tablets- Hypodermic tablets are soft,

readily soluble tablets and were originally used for the preparation of solutions to he injected. Since stable parenteral solutions are now available for most drug substances, there is no justification for the use of hypodermic tablets for injection. Their use in this manner should be discouraged since the resulting solutions are not sterile.

13. Immediate release tablet- Immediate release tablets are

formulated to release the active drug immediately after oral administration. In the formulation of conventional drug products, no deliberate effort is made to modify the drug release rate. Immediate-release products generally result in relatively rapid drug absorption and onset of accompanying pharmacodynamic effects.

14. Instantly disintegrating or dissolving tablet- Instant-release tablets (rapidly

dissolving tablets or RDTs) are characterized by disintegrating or dissolving in the mouth within 1 minute, some within 10 seconds. Tablets of this type are designed for children and the elderly or for any patient who

has difficulty in swallowing tablets. They liquefy on the tongue, and the patient swallows the liquid.

15. Extended release tablet- Extended-release tablets

(sometimes called controlled-release tablets) are designed to release their medication in a predetermined manner over an extended period of time.

16. Vaginal tablet- Vaginal tablets, also called

vaginal inserts, are uncoated, bullet-shaped or ovoid tablets inserted into the vagina for local effects. They are prepared by compression and shaped to fi t snugly on plastic inserter devices that accompany the product. They contain antibacterials for thetreatment of nonspecific vaginitis caused by Haemophilus vaginalis or antifungals for the treatment of vulvovaginitis candidiasis caused by Candida albicans and related species.