Classification of powders

Classification of Powders

1. CLASSIFICATION OF POWDERS RESHMA FATHIMA K ASSISTANT PROFESSOR GRACE COLLEGE OF PHARMACY

2. Bulk Powders for external use Bulk powder meant for external use are non potent substances. These powders are supplied in cardboard, glass or plastic containers, which are often designed for the specific method of application. The dusting powders are preferably supplied in perforated or sifter top containers. The container should bear a label indicating that the powder is meant for external application.

3. The bulk powders which are commonly used for external applications are as follows: Dusting Powders Insufflations Snuffs Dentifrices

4. Dusting powders These are meant for external application to the skin and are generally applied in very fine state of subdivision to avoid local irritation. Hence dusting powders should be passes through sieve no: 80 to enhance their effectiveness. Dusting powders are of two types: Medical Surgical

5. Medical dusting powders are used mainly for superfacial skin conditions, whereas surgical dusting powders are used in body cavities and also on major wounds as a result of burns and umbilical cord of infants. Surgical dusting powders must be sterilized before their use, whereas medical dusting powders must be free from pathogenic microorganisms.

6. Dusting powders are generally prepared by mixing two or more ingredients one of which must be either starch, talc or kaolin as one of the ingredients of the formulation. Talc and Kaolin are more commonly used because these are chemically inert Dusting powders are dispensed in sifter top container or aerosol containers. Dusting powders are generally considered to be non toxic but the inhalation of its fine powdered ingredients by infants may lead to pulmonary inflammation. So proper care must be taken while handling these preparations.

7. It is mainly used for their antiseptic, astringent, absorbent, and antipruritic action. Dispense 50g of dusting powders Rx Purified talc, sterilized 50.0g Starch in powder 25.0g Zinc oxide in powder 20.0g Salicylic acid in powder 5.0g Make a powder

8. Direction: Applied on the affected part two or three times a day Method: Powder all the ingredients. Weigh the required quantity of purified talc, starch, zinc oxide and salicylic acid. Mix them in ascending order of their weight. Pass the mixed powder through a sieve no 85. after sifting again mix lightly. Transfer the powder in sifter top containers to protect it from atmospheric contaminations.

9. Insufflations These are medicated dusting powders meant for introduction into the body cavities such as ear, nose, vagina and throat with the help of an apparatus known as “ insufflator” It sprays the powder into a stream of finely divided particles all over the site of application. The following difficulties are however generally faced while using the insufflators. It is difficult to obtain a measured quantity of the drug as a uniform dose. It gets blocked when it is slightly wet or the powder used is wet

10. Insufflations are used to produce a local effect, as in the treatment of ear, nose and throat infection with antibiotics or to produce a systemic effect from a drug that is destroyed in the gut. Snuffs These are finely divided solid dosage forms of medicament which are inhaled into nostrils for its antiseptic, bronchodilator and decongestion action. Snuffs are dispensed in flat metal boxes.

11. Dentifrices These are applied with the help of a tooth brush for cleaning the surface of the teeth. They contain a suitable detergent or soap, some abrasive substance and a suitable flavor. The abrasive agents such as calcium sulphate , magnesium carbonate, sodium carbonate and sodium chloride are used in fine powder. A strong abrasive substance should however not to be used as it may damage the tooth structure.

12. Dispense 50.0g of dentifrices Rx Hard soap, in fine powder 50.0g Precipitated calcium carbonate 935.0g Saccharin sodium 2.0g Peppermint oil 4.0g Cinnamon oil 2.0ml Methyl salicylate 8.0ml Make a tooth powder

13. Direction: To be applied on the surface of the teeth with the help of tooth brush. Method: Triturate the saccharin sodium, the oil and methyl salicylate with about one half of the precipitated calcium carbonate and mix the soap with the remaining portion of the precipitated calcium carbonate. Mix the two powders thoroughly and then pass it through a fine sieve.

14. Simple and Compound Powders for Internal use In this form of powder, each individual dose is enclosed in paper. The number of ingredients may be one (simple powder) or more than one powder (compound powder). The minimum quantity of each powder should not be less than 100mg so that it can be handled conveniently by patient and can be weighed accurately. The following rules should be observed: Weigh the ingredients after calculating for one extra powder. If the quantity of an ingredient is not directly weighable, calculate for sufficient extra powders to produce directly weighable quantity. In case of potent ingredient, calculate the amount of lactose to be mixed to make each powder directly weighable.

15. Simple powder A simple powder contains only one ingredient either in crystalline or amorphous form. When the powder is in crystalline form, it is reduced to fine powder, weighed the powder and divided into number of doses and wrapped as individual doses. Dispense six powders of aspirin each powder contains 300mg of aspirin. Rx Aspirin 300mg Make a powder Direction: One powder to be taken after every eight hours

16. Method: Powder the aspirin and weigh the required quantity of aspirin. Weigh 300mg of aspirin for each powder. Wrap each dose in individual powder paper. Prepare six such powder. Pack it flap to flap and restrained with elastic band. Compound Powders Compound powders contain more than two substances which are mixed together and then divided into desired number of individual doses which are dispensed into each powder paper. Dispense eight powders of A.P.C Rx Aspirin 300mg Paracetamol 150mg Caffeine 50mg Make a powder

17. Direction: One powder to be taken when need arises Method: Powder all the ingredients and weigh the calculated quantity of each ingredient. Mix them in ascending order of their weight. Weigh 500mg of the mixed powder for each powder. Wrap each dose in individual powder paper. Pack in pairs flap to flap and restrained with elastic band.

18. Cachets consists of a dry powder enclosed in a shell. The shell is prepared from a mixture of rice flour and water by moulding into suitable shape and then dried. Two types of cachets are there: (i) Wet seal cachets: lower half of the cachet is filled with powdered drug. Then the flange of the empty upper half of the cachet is moistened with water, and pressed over the lower half. The cachet is dried for 15 minutes .

19. ii)Dry seal cachets: Drug powder is filled in the lower half and the upper half is pressed over it just like a capsule. Use: They are used for administering the drug with unpleasant taste and a large dose. Before administration, a cachet should be immersed in water for few seconds and then placed on the tongue and swallowed with water. e.g. Sodium aminosalicylate cachets Sodium aminosalicylate and isoniazid cachtets

20. Packing and storage of cachets: The cachets are packed in boxes or tins in which they are placed on their edges or lying flat. The container containing cachets should be labelled with a direction for its use; immerse in water for a few seconds and then swallow with a draught of water.

21. Tablet Triturates These are powders molded into tablets. Molded tablets are flat, circular disc and usually contains a potent substances which is mixed with lactose, dextrose or some other suitable diluent. The apparatus used for the preparation of tablet triturates is made of stainless steel or plastic.

22. It consists of an upper perforated plate which is having an exactly the same no of holes as that of number of pegs in a lower plate. The lower plates also have two large pegs which ensure correct fitting of the plates. The molds arev