Powder- Solid dosage form ppt


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Mr.P.B.Awate Lecturer College of Pharmacy,(poly.), Pandharpur POWDERS


Content Definition of powders Advantages &disadvantages of powders Types of powder Bulk powder for internal use Bulk powder for external use Cachets Tablet triturates Problems encountered during dispensing of powders


Definition Definition:- Powders are the solid dosage form of drug in fine state of division in dry form, intended for internal or external use.

Advantages :

Advantages Internal &external use. More stable than liquid. Convenient for the physician. Chances of less incompatibility. Onset of action is rapid. Easy to carry. Large quantity can be administered. Convenient for small child & elderly patient. More economical .


Disadvantages Can’t dispense bitter, nauseous & unpleasant taste drug. Can’t dispense hygroscopic & deliquescent drugs. Dispensing is time consuming process. Quantity less than 100mg can’t weigh on dispensing balance. Can’t dispense volatile drugs.

Types of Powders:

Types of Powders 1) Divided powders packets cachets capsules 2) Undivided (Bulk) powders dusting powder effervescent powder OR Bulk powders for internal use. Bulk powders for external use. Simple & compound powder for internal use. Powder enclosed in cachets & capsule. Compressed powders(tablets)

Bulk Powder For External Use :

Bulk Powder For External Use Bulk powder for external use:  Bulk powder for external use Supply non potent drug. Supply in cardboard, glass or plastic container. Also in sifter top container. Types:-. dusting powder Insufflations Snuffs Dentifrices  

Bulk Powder For External Use :

Bulk Powder For External Use Dusting Powder:  These are meant for external application on to the skin and are generally applied in a very fine state of subdivision to avoid local irritation. Types: Medical Surgical 1) Medical dusting powders:  They are used for superficial skin conditions, they should not be used for application to open wounds or application or broken skin. The label should clearly specify this point. We need not sterilize the ingredients of these powders but we must be sure that they are not containing pathogens. 2) Surgical dusting powders:  Uses: - in body cavities, on major wounds as a result of burns and umbilical cords of infants. Surgical dusting powders must be sterilized before their use.

Bulk Powder For External Use :

Bulk Powder For External Use Dusting powder Requirements:   Homogenous and very fine Free from irritation. Flow easily. Have good covering capacity. Have good adsorptive and absorptive capacity. Spread uniformly over body surface. Cling to skin surface after application. Protect the skin from irritation caused by friction, moisture and chemical irritants.

Bulk Powder For External Use :

Bulk Powder For External Use Dentirifices (Tooth Powders ):- Dentirifices are preparations which are generally used with the help of tooth brush for cleansing the surfaces of the teeth. They are available in the form of fine powders and pastes . They contain Abrasive like calcium sulfate, magnesium carbonate, sodium carbonate in fine powder Detergent or soap Binder Humectant Sweetening agent e.g. saccharin sodium Flavour e.g. peppermint oil, clove oil . Opacifiers Colouring agent

Bulk Powder For External Use:

Bulk Powder For External Use Insufflation:- These are fine powders which are used to produce either a local effect, such as in the treatment of ear or nose or throat infections or a systemic effect, such as when they are inhaled into the lungs and get absorbed from the lungs. If a drug is destroyed in the GIT, when it is taken orally, then making it into an insufflation is a good option. Making a drug into a fine powder, packing it into containers called inhalers, seeing that the powder goes and lodges in the lungs and then releases the drug there involves a lot of technology. But if that can be managed, it is a good dosage form, because absorption of drug from the lungs is very fast, the lungs are highly perfused and the area offered for absorption is equal to the area of a tennis court!

Bulk powder for external use :

Bulk powder for external use Snuffs:  These are finely divided solid dosage forms of medicament are inhaled into nostrils for its antiseptics, bronchodilator and decongestion action .

Simple powder & compound powder for internal use  :

Simple powder & compound powder for internal use  Simple powder: - contain only one ingredient Compound powder: - contain two or more than two substances mix together

Cachets :

Cachets Enclosure in cachets provides a means of administering nauseous or disagreeable powders in a tasteless form. Cachets are moulded from rice paper, a material made by pouring a mixture of rice flour and water between two, hot. Polished, revolving cylinders; water evaporates and sheet of wafer is formed . Types of cachets:- :  Types: - Wet seal Dry seal 1 ) 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 .


Cachets 2) 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.

Preparation of powders:

Preparation of powders Reduction of particle size of all ingredients Sieving. Weighing of each ingredient. Mixing. Packaging.

Methods of Powder Mixing:

Methods of Powder Mixing Mechanical Mixing 2) Hand Mixing: Spatulation (spatula + tile) Trituration (mortar + pestle) Tumbling (wide mouth closed container) 3) Geometric dilution: Entire quantity of potent drug (x volume) + (x volume) of the diluents + (2x volume) of the diluents + (4x volume) of the diluents………repeated until all the diluents are used .

Problems encountered in powder formulation:

Problems encountered in powder formulation 1- Hygroscopic and Deliquescent Powder Problem: Absorption of moisture from air leading to partial or complete liquefaction. Solution: Applied in a granular form to decrease the exposed surface to air. Packed in aluminum foil or in plastic film packets Addition of light magnesium oxide to reduce the tendency to damp Addition of adsorbent materials such as starch

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2- Efflorescent powders Problem: Crystalline substances which during storage loose their water of crystallization and change to powder (to be efflorescent). The liberated water convert the powder to a paste or to a liquid. Examples: Alum, atropine sulfate, citric acid, codeine phosphate Solution: Using the anhydrous form, I n a manner similar to hygroscopic powders

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3- Eutectic Mixtures Problem: mixture of substances that liquefy when mixed, rubbed or triturated together. The melting points of many eutectic mixtures are below room temperature. Examples: menthol, thymol, phenol, salol, camphor Solution: Using inert adsorbent such as starch, talc, lactose to prevent dampness of the powder 2. Dispensing the components of the eutectic mixture separately.

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4- Incorporation of Liquids Solution: The liquid is triturated with an equal weight of the powder and the remaining powder is added in several portions with trituration. Adsorbent is incorporated, usually light kaolin.

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5- Incorporation of Extracts Problem: Some plant extracts are available as powders or as semisolid (e.g., liquid extract of liquorice) . Solution: The powdered extracts have no problems and treated generally as powders Semisolid extract should be mixed with an equal quantity of lactose and reduced to a dry powder by evaporation before incorporation with other ingredients. Careful heating, if present, to save potency of the extract.

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6- Potent Drug Problem: Limited precision and accuracy of the used balances to weight small amounts of potent drugs. Solution: Drug triturates: Suitable diluents like lactose are mixed with the potent drug to form 10 - 20%w/w drug triturates. Very fine powders should be used in the triturates Geometric dilution to prepare drug triturates

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7- Incompatible salts Problem: Chemically incompatible salts when triturated together produce discoloration, chemical deterioration or loss of potency. Solution: Compounding such substances with minimum pressure Use a convenient method for mixing the powder like tumbling in a jar or spatulation on a sheet of paper. Each substance should be powdered separately in a clean mortar and then combined with other ingredients gently. Powder and dispense separately.

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8- Explosive mixtures Problem: Oxidizing agents(ex. Pot. Salts of chlorate, dichromate, permanganate and nitrate Sod. Peroxide, silver nitrate and silver oxide) explore violently when triturated in a mortar with a reducing agent ( ex. Sulfides, sulfur, tannic acid, charcoal). Solution: Comminute each salt separately. Subject to a minimum pressure.

Effervescent Powders:

Effervescent Powders Definition: Mixture of organic acid and alkali effervesces when subjected to water due to reaction between the acid and the base with evolution of co 2 Examples: Citric or tartaric acids with sodium carbonate or bicarbonate Uses: The liberated carbon dioxide has the following advantages: It masks the bitter and nauseous taste. It promotes gastric secretions. It acts as a carminative. psychological impression at the patient. .

Effervescent Powders:

Effervescent Powders Formulation: Bulk powders or divided powders Packed in separate packages of contrasting colors. The contents are mixed in a quantity of water at the time of dosing. The liquid is consumed just after the reaction begin to subside.

Effervescent Granules:

Effervescent Granules Definition: Sweetened effervescent powders formulated as granules. Granulation: 1- Wet method: By the addition of a binding liquid (Alcohol is frequently used). 2- Dry method: Heating effloresced powder to liberate the water of crystallization which then acts as the binding agent

Effervescent Granules:

Effervescent Granules Wet Granulation Procedure: The powders are mixed without pressure in a suitable container. Alcohol is added in portions with stirring until a dough like mass is formed. The materials are then passed through sieve # 6. The resulted granules are dried at a temperature not exceeding 50ºC. The granules are packed in air tight containers

Effervescent Granules :

Effervescent Granules Dry granulation Procedure: All ingredients, except citric acid monohydrate, are dried and passed through sieve # 60. The powders are thoroughly mixed and citric acid crystals are added at last (un-effloresced citric acid contains one molecule of water of crystallization). The mixture is spread in a shallow dish and placed in an oven previously heated (99- 105ºC). Upon heating citric acid crystals, the water of crystallization effloresces and citric acid transforms to the powder form. The use of a water bath surrounding the beaker (or any container) in which the powders are stirred is a more convenient method to prevent local over heating. No stirring until the powders become moist and form doughy mass. The mass is then granulated by passage through sieve # 6 and dried.

Effervescent Granules:

Effervescent Granules Packaging: * Effervescent granules or powders suffer from the short shelf life, especially if they are filled into wide-mouthed screw capped containers. * Recently, the stability of effervescent granules and powders is greatly improved by their packing in aluminum bags tightly closed.

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Weighing technique for the dispensing balance:  The balances should always be sited on a convenient level surface . Clean the balance and pans as necessary. A clean sheet of white demy paper should be placed under the pans helps to contain spillage and protect the balance. Select a suitable weighing vessel or paper. Balance pans are usually made of glass or stainless steel and are resistant to direct contact with most medicaments with a few exceptions. Weighing papers are convenient for bulky powders and may facilitate transfer from the balance. For greasy or waxy constituents, greaseproof paper should be used since white demy partly absorbs greasy substances and transfer from the paper is difficult. Check that the pointer is on the null point but is able to move freely. Place the required weights on the left-hand pan – use forceps to avoid contamination of the weights Close the balance drawer. This prevents spills from contaminating Collect the medicament from the shelf. Check the label. Hold the bottle in the left hand. Keep the label uppermost so that it is visible during weighing. Use a spatula to transfer the medicament to the right hand pan until the pointer returns to the null point. Powders should not be shaken onto the pan from the container. Close the stock container Recheck the weights and the medicament against the formula.

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