Introduction of Tablets

TABLETS

DEFINITION:

Tablets are solid dosage forms each containing a unit dose of one or more medicament.

INTRODUCTION:

They are intended for oral administration. Some tablets are swallowed whole or after being chewed, some are dissolved or dispersion in water before administration and some are retained in mouth where the active ingredient is liberated. Preparation intended for administration by other routes, for example, in the form of implants and passerines may also be presented in the form of tablets but because they may required special formulations, methods of manufacture or from of presentation appropriate to the particular use they may not comply with all the requirement of this monograph.

Tables are obtained by compression of uniform volumes of powders or granules by applying high pressure and using punches and dies. The particles to be compressed consist of one or more medicaments, with or without auxiliary substance such as diluents, binders, and disintegration agents, lubricant, glide ants and substances capable of modifying the behavior of the medicaments inn the digestive tracts. Such substances must be innocuous and therapeutically inert in the quantities present.
   
Because of their composition, method of manufacture or intended use, tablets present variety of characteristics and consequently there are several categories of tablets.
   
Useless otherwise stated in the individual monograph, tablets are uncoated. Where coating is permitted the monograph directs coating the statement reads “The tablets are coated “
Unless otherwise directed, tablets may be coated in one of different ways.

GENERAL CHARACTERSTICS:

Tablets are usually solid, right circulars cylinders, the end surfaces of which are flat or convex and the edges of which may be beveled, they may exist in others shapes like triangular, rectangular, etc also. They may have lines or break-marks and may bear a symbol or other markings. They are sufficiently hard to withstand handling without crumbling or breaking.

INDIAN PHARMACIA REQUIREMENTS:

UNCOATED TABLETS:

Uncoated tablets may be signal-layer tablets resulting from a signal compression of particles or multi-layer tablets costing of parallel layers obtained by successive compression of particles of different compositions ., no treatment is applied to such tablets after compression Any added substances are not ingredients in the digestive fluids

The addition of coloring or flavorings agents to uncoated tablets other than multi-layer tablets is not official unless permitted in the individual monograph. Uncoated tablets have the general characteristics of tablets. When a bracken section of uncoated tablet if the tablets fail to comply the discs the tablets comply the if all six have disintegrated.

 
INDIAN PHARMACOPEIAL REQUIEMS

COATED TABLETS:
 
Coated tablets are covers with one or more layers mixture of various substances such as resins, gums, inactive, and insoluble fillers, sugars, plasticizes polyhydric alcohols, waxes, etc. the coating may also contain medicaments in compression-coated tablets the coated is applied by compressing around the tablets granules prepared from tablets the coating is applied as a   coating are usually applied as a solution or suspension in condition in which evaporation of the vehicle occurs. When the coating is thin, the tablets are described as a film coated. Coated tablets may contain flavoring and or one or more coloring agents permitted under the drug and cosmetic rules 1945
   
Coated tablets have a smooth. Usually polished and after colored. Surface: a broken sections examined under a lens shows a core surrounded by one or one more continuous layers of a different texture.

BRITISH PHARMACOPEIAL REQUIREMENTS:
              
DISINTEGRATION TESTS:

Coated tablets other than film-coated tablets comply the test for disintegration of tablets and capsules use water R a liquids medium add a disc to each tube operate the apparatus for 60 minuets unless otherwise justified and authorized and examine the state of the tablets if any has not disintegrated repeats the test on a further six tablets replacing water R which 0.1 M hydrochloric acid the tablets comply with the test if all six tablets have disintegrated in the acid medium.

Film–coated tablets comply with the disintegration test pre cribbed over expect that the apparatus is operated for 30 minute unless otherwise justified and authorized.
If coated tablets or film-coated tablets fail to comply because of adherence to the discs repeat the test on a further six tablets omitting the discs the tablets comply with the test if all six have disintegrated.

INDIAN PHARMACOPEIAL REQUIREMENTS:

ENTERIC-COATED TABLETS

Enteric –coated tablets (gastric –resistant tablets) are tablets with one or more layers of coatings intended to resist the gastric fluid but to release their active ingredients in the intestinal fluid. For this purpose substance such as acetate phthalate and anionic copolymer of met acrylic acid and its ethers are used for providing tablets with a gastric\-resistant coating to for covering either granules or particles with gastric –resistant coating Enteric–coated tablets have the characteristics of coated tablets.

BRITISH PHARMACOPEIAL REQUIREMENTS:

PRODUCTION:

For tablets prepared form granules or particles already covered with a gastro-resistant coating a Suitable test is carried out to demonstrate of the active substances

DISINTEGRATION TESTS:

For tablets wit a gastro-resistance coating carry out the test for disintegration with the following modifications use 0.1 M hydrochloric acid. As the liquid medium operate the apparatus for 2 hr or other such time as may be joisted and authorized without the discs and ermine the tablets the time of resistance to the acid medium various according to the formulation of the tablets to be examined it is typically 2 hr to 3 hr but even with authorized deviations is not less than 1 hr No tablets show signs of either disintegrations (apart from the fragment of coating ) or creaks  that would that allow the escape of the contents Replace the acid by phosphate buffer solution pH 6.8 R and a disc  to each  tube. Operate the apparatus for the 60 minutes and examine and the state of each tablets if the tablets fail to comply of adherence to the discs, repeat the test on a further six tablets omitting the discs the tablets comply with the test if all have disintegrated .

INDIAN PHARMACOPEIAL REQUIREMENTS:

DISINTEGRATION TESTS:

Dispersible tablets are uncoated tablets that procedure a uniform dispersion in water and May contains permitted colorings and flavorings agents.

FINENESS OF DISPERSION:

Place two tablets in 100 ml of water R and stir completely dispersed a smooth dispersion is produce which oases though a serve screen with a nominal mesh aperture is procure of 710 micro meters.

INDIAN PHARMACOPEIAL REQUIREMENTS:

MODIFIED – RELEASE TABLETS:
   
Modified – release tablets (Sustained– releases tablets) are coated ort uncoated containing auxiliary substances or prepared by procedures that separately or together, are designed to modify the rate or the place at which the ingredients is released.

BRITISH PHARMACOPEIAL REQUIREMENTS:

PRODUCTION:

A suitable test is carried out to demonstrate the appropriate release of the active ingredients.

INDIAN PHARMACOPEIAL REQUIREMENTS:
   
SOLUBLE TABLETS:

Soluble tablets are uncoated that dissolve in water. The solution may be slightly opalescent due to added substances used in the manufacture of the tablets.

BRITISH PHARMACOPEIAL REQUIREMENTS:

DISITEGREATIUON TEASTS:
   
Soluble tablets disintegrate within 3 minutes when examined by the test for disintegration of tablets and capsules, but water R at 15 to 25 degree C.
   
INDIAN PHARMACOPEIAL REQUIREMENTS:

EFFERVENCENT TABLETS:

Effervescent tablets are uncoated tablets generally containing acidic substances and either carbonates or bicarbonates , which react rapidly in the presence of water to release carbon dioxide they are intended to be dissolved or dispersed in water before administration,

BRITISH PHARMACOPEIAL REQUIREMENTS:

DISITEGREATIUON TEASTS:

Place tablets in a breaker containing 200 ml of water R at 15 degree to 25 degree: numerous bubbles of gas are evolved when the evolution of gas around the tablets or its fragments creases the tablets has disintegrated, being either dissolved or dispersed in the water sp that no agglomerates of particles remain. Repeat the oration on five other tablets the comply with the if each of the six tablets used disintegrates in the manner prescribed within 5 minutes, unless otherwise justified and authorized.


TABLETS FOR USE IN THE MOUTH:

Tablets for use in the mouth are usually uncoated tablets to be chewed or to affect a slow release and local action of the active ingredients (lozenges) or the release and absorption of the active ingredients under the tongue (sublingual tablets).     


STANDARDS:

Uniformity of container contents:
Tablets comply with the test for contents of packaged dosage forms, Appendix 11.2

CONTAENTS OF PACKGED DOSAGE FROMS:
   
The following tests and specification apply to oral dosage forms and preparations intended for topical use that use that are packaged in containers in which the labeled net quantity is not more than 100g or 300ml or 1000 units, as the case many be. For higher labeled quantities the test and limit given in the stammered of weighing and measure (Packaged commodities).

CONTENT OF THE ACTIVE INGREDIENT:

Determine the Amount of active ingredients by the method described in the assay and calculate the amount of active ingredients started in the monograph this range is based on the requirements that 20 tablets or such other numbers as may be indicated in there monograph are used in the assay where 20 tablets cannot be obtained , a small  number  which must not be less than 5 may be used  but to allow for sampling errors the tolerances are winded in accordance with table 1 the requirements of table 1 apply when the stated limits are between 91 and 110% for the limits than 90 to 110% proportionately smaller or larger allowances should be made


UNIFORMITY OF WEIGHT:

This is not applicable to coated tablets other than film-coated to tablets that are required to comply with the test for uniformity of content for all active ingredients.
   
Weight 20 tablets selected at random and cal cute the average weight not more than two individual weight deviate by more than the percentage shown in table-2 and none deviates by more than twice that percentage.


AVERAGE WEIGHT OF TABLET    PERCENTAGE DEVIATION
80 mg more less                                            10
More than 80mg but less than 250mg              7.5
250 mg or more                                               5


UNIFORMITY OF CONTENT:

This test is applicable to tablets that contain less 10mg or less than 10% w/w of active ingredient for  tablets containing more than active ingredient carry out the test for each active ingredient that corresponds to the aforementioned conditions.

This trust for uniformity of content should be cared out after only the content the active ingredients in a pooled sample of the started content. The test for uniformity of contently is not applicable to tablets containing multivitamins and trace elements.

Determine the content of the active ingredient in each of 10 tablet at random using method given in the monograph or by any other suitable analytical method the tablets comply with there test if not more of the individual values are outside the limits 75 to 125% repeat the determination using another 20 tablet the tablet comply with the test if in individual values are outside the limit 85 to 115% and outside the limits 75 to 125 % of the average value.