tablet (pharmacy) tablet (pharmacy) a tablet (also known as a pill) is a pharmaceutical oral dosage form (oral solid dosage, or osd) or solid unit dosage form. tablets may be defined as the solid unit dosage form of medication with suitable excipients. it comprises a mixture of active substances and excipients, usually in powder form, that are pressed or compacted into a solid dose. the main advantages of tablets are to ensure a consistent dose of medicine that is easy to consume. common disk-shaped tablets tablets are prepared either by moulding or by compression. the excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tabletting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive or aid in visual identification of an unknown tablet. a polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment (extending its shelf life), or to enhance the tablet's appearance. medicinal tablets were originally made in the shape of a disk of whatever colour their components determined, but are now made in many shapes and colours to help distinguish different medicines. tablets are often imprinted with symbols, letters, and numbers, which allow them to be identified, or a groove to allow splitting by hand. sizes of tablets to be swallowed range from a few millimetres to about a centimetre. the compressed tablet is the most commonly seen 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 in the body; it is usually taken orally, but can be administered sublingually, buccally, rectally or intravaginally. the tablet is just one of the many forms that an oral drug can take such as syrups, elixirs, suspensions, and emulsions. history pills are thought to date back to around 1500 bc. earlier medical recipes, such as those from 4000 bc, were for liquid preparations rather than solids. the first references to pills were found on papyruses in ancient egypt, and contained bread dough, honey or grease. medicinal ingredients, such as plant powders or spices, were mixed in and formed by hand to make little balls, or pills. in ancient greece, such medicines were known as katapotia ("something to be swallowed"), and the roman scholar pliny, who lived from 23 to 79 ad, first gave a name to what we now call pills, calling them pilula. pills have always been difficult to swallow and efforts long have been made to make them go down easier. in medieval times, people coated pills with slippery plant substances. another approach, used as recently as the 19th century, was to gild them in gold and silver, although this often meant that they would pass through the digestive tract with no effect. in the 1800s sugar-coating and gelatin-coating was invented, as were gelatin capsules. in 1843, the british painter and inventor william brockedon was granted a patent for a machine capable of "shaping pills, lozenges and black lead by pressure in dies". the device was capable of compressing powder into a tablet without use of an adhesive. types pills combined oral contraceptive pills were nicknamed "the pill" in the 1960s a pill was originally defined as a small, round, solid pharmaceutical oral dosage form of medication. the word's etymology reflects the historical concepts of grinding the ingredients with a mortar and pestle and rolling the resultant paste or dough into lumps to be dried. today, in its strict sense, the word pill still refers specifically to tablets (including caplets) rather than capsules (which were invented much later), but because a simple hypernym is needed to intuitively cover all such oral dosage forms, the broad sense of the word pill is also widely used and includes both tablets and capsules — colloquially, any solid oral form of medication falls into the "pill" category (see pill § usage notes). an early example of pills came from ancient rome. they were made of the zinc carbonates hydrozincite and smithsonite. the pills were used for sore eyes, and were found aboard a roman ship that wrecked in 140 bc. however, these tablets were meant to be pressed on the eyes, not swallowed. caplets variations on a common tablet design, which can be distinguished by both colour and shape a caplet is a smooth, coated, oval-shaped medicinal tablet in the general shape of a capsule. many caplets have an indentation running down the middle so they may be split in half more easily. since their inception, capsules have been viewed by consumers as the most efficient method of taking medication. for this reason, producers of drugs such as otc analgesics wanting to emphasize the strength of their product developed the "caplet", a portmanteau of capsule-shaped tablet, in order to tie this positive association to more efficiently produced tablet pills, as well as being an easier-to-swallow shape than the usual disk-shaped tablet. olanzapine tablets orally disintegrating tablets (odt) an orally disintegrating tablet or orodispersible tablet (odt), is a drug dosage form available for a limited range of over-the-counter (otc) and prescription medications. film coated tablets (fct) a film coated tablet is a drug dosage form available for a limited range of over-the-counter (otc) and prescription medications. the used films protect the drug substance against denaturation by stomach acid and/or support a delayed (modified) release of the drug substance ("retard effect"). such tablets should not be crushed or chewed before swallowing. tabletting formulations bottles in the tablet-pressing process, it is important that all ingredients be fairly dry, powdered or granular, somewhat uniform in particle size, and freely flowing. mixed particle sized powders segregate during manufacturing operations due to different densities, which can result in tablets with poor drug or active pharmaceutical ingredient (api) content uniformity, but granulation should prevent this. content uniformity ensures that the same api dose is delivered with each tablet. some apis may be tableted as pure substances, but this is rarely the case; most formulations include excipients. normally, a pharmacologically inactive ingredient (excipient) termed a binder is added to help hold the tablet together and give it strength. a wide variety of binders may be used, some common ones including lactose, dibasic calcium phosphate, sucrose, corn (maize) starch, microcrystalline cellulose, povidone polyvinylpyrrolidone and modified cellulose (for example hydroxypropyl methylcellulose and hydroxyethylcellulose). often, an ingredient is also needed to act as a disintegrant to aid tablet dispersion once swallowed, releasing the api for absorption. some binders, such as starch and cellulose, are also excellent disintegrants. tablet properties tablets can be made in virtually any shape, although requirements of patients and tableting machines mean that most are round, oval or capsule shaped. more unusual shapes have been manufactured but patients find these harder to swallow, and they are more vulnerable to chipping or manufacturing problems. tablet diameter and shape are determined by the machine tooling used to produce them - a die plus an upper and a lower punch are required. this is called a station of tooling. the thickness is determined by the amount of tablet material and the position of the punches in relation to each other during compression. once this is done, we can measure the corresponding pressure applied during compression. the shorter the distance between the punches, thickness, the greater the pressure applied during compression, and sometimes the harder the tablet. tablets need to be hard enough that they do not break up in the bottle, yet friable enough that they disintegrate in the gastric tract. tablets need to be strong enough to resist the stresses of packaging, shipping and handling by the pharmacist and patient. the mechanical strength of tablets is assessed using a combination of simple failure and erosion tests, and more sophisticated engineering tests. the simpler tests are often used for quality control purposes, whereas the more complex tests are used during the design of the formulation and manufacturing process in the research and development phase. standards for tablet properties are published in the various international pharmacopeias (usp/nf, ep, jp, etc.). the hardness of tablets is the principal measure of mechanical strength. hardness is tested using a tablet hardness tester. the units for hardness have evolved since the 1930s, but are commonly measured in kilograms per square centimetre. models of tester include the monsanto (or stokes) hardness tester from 1930, the pfizer hardness tester from 1950, the strong cob hardness tester and the heberlain (or schleeniger) hardness tester. lubricants prevent ingredients from clumping together and from sticking to the tablet punches or capsule filling machine. lubricants also ensure that tablet formation and ejection can occur with low friction between the solid and die wall, as well as between granules, which helps in uniform filling of the die. common minerals like talc or silica, and fats, e.g. vegetable stearin, magnesium stearate or stearic acid are the most frequently used lubricants in tablets or hard gelatin capsules. manufacturing