Granules

1. GRANULES

2. DEFINITION Granules are prepared agglomerates of smaller particles of powders. they are irregular shaped but May be prepared to be spherical. Granules size ranges between 0.2 to 4.0 mm depending upon use of granules

3. granulation The process in which the primary powders particles are Made adhere to form larger Multi particle entities called granulation.

4. REASON FOR GRANULATION To prevent segregation of the constituents of powder Mix To improve the flow properties of the powder mix To improve the compaction characteristics of powder mix

5. ADVANTAGES OF GRANULES Granules are usually made as a step to prepare tablets. Granules flow into the dies more evenly and more freely than particles from the hopper. A few advantages of granules over powders are listed below: Granules flow better than powders. The easy flow characteristics are important in supplying drug materials from the hopper or feeding container into the tableting presses. For this reason powder mixtures are usually granulated if they are intended to be compressed into tablets. Granules also eliminate or control dust.

6. Granules have smaller surface area than a comparable volume of powders. This makes granules more stable physically and chemically than the corresponding powders. Granules are less likely to cake or harden upon standing than are powders.

7. Granules are more easily wetted by a solvent than are certain powders, so that granules are also preferred in making solutions. Example: Principen ® ( ampicillin ) for Oral Suspension (Squibb). Ampicillin is unstable in aqueous solution, so it is usually prepared as granules and reconstituted by a pharmacist with purified water just prior to dispensing. The granules also contain colorants, flavorants , and other pharmaceutical ingredients, so the resulting solution or suspension has all the de-sired medicinal and pharmaceutical features of a liquid pharmaceutical.

8. Granules produce particle-size uniformity, thus content uniformity. Granules increase compressibility.

9. METODS OF GRANULATION Granules are prepared by two methods Wet granulation Dry granulation

10. WET GRANULATION Usually wet granulation is done in two manners One method is to moistened the powder or powder mixture and then pass through a screen of the mash size to produce the desire size of granules. these granules are dried by using dry heat. Another types is bed processing in which particles are placed in a conical piece of equipment and are vigorously dispersed and suspended wile liquid excipient is sprayed on particles and dried.

11. dry granulation Dry granulation is also done in couple of ways The dry powder is passed trough a roll compactor and than through a granulating machine. Roll compactor processes a fine powder into dense sheet. The compacted powder is granulated to uniform particle size. then used in formation of different textures.

12. continuation Compression of a powder mixture into a large tablets on a compressing machine under 8000 to 12000lb of pressure.

13. examples Biaxin granules for oral suspension(abbot) Omnicef for oral suspension(abbot) Augmenton ES-600(GLAXOSMITH KLINE0) Effervescent granules

14. Effervescent granulated salts Effervescent salts are granules or coarse to very coarse powder containing a medicinal agent in a dry mixture usually composed of sodium bicarbonate, citric acid and tartaric acid . When added to water the acid and base react to liberate carbon dioxide resulting in effervescence. The resulting carbonated solution mask the undesirable taste of medicinal agent. effervescent tablets and granules are dissolve in water before use

15. preparation Effervescent granules are prepared by two general methods. The dry or fusion method The wet method

16. Dry or fusion method In fusion method the one molecule of water present in each molecule of citric acid acts as the binding agent for the powder mixture. Before mixing the powder the citric acid crystals are powdered and then mixed with other powders of the same size to ensure uniformity of the mixture. After mixing te powder is placed in an oven at 34- 40 degree centigrade .

17. continuation Heating cause te release of water of crystallization from te citric acid so dissolve some portion of powder this cause the softening of powder when it reached the proper consistency it is removed from the oven and rubbed through a sieve produced large granules. Sieve 4 produce large granules sieve 8 produce medium size granules and sieve 10 produce small granules dry at 54 degree centigrade and placed in tight container.

18. Wet method The source of binding agent is not water of crystallization from the citric acid but the water added to alcohol as moistening agent forming the pliable mass of granulation. In this method all of powder may be anhydrous as long as water is added to the moistening agent.

19. Continue…………… Just enough liquid is added to prepare a mass of proper consistency then the granules are prepared and dried.

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