Powder dosage forms
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Pharmaceutical powders are finely divided mixtures of drugs or chemicals used for internal or external applications. They have advantages like better chemical stability and faster dissolution rates, but can present challenges such as accurate dosing and the physical properties of hygroscopic materials. The document also covers various preparation methods, types of powders, and formulations used for specific applications, including internal use and specialized powders.
Powder dosage forms
- 1. POWDERS Parag Jain Assistant Professor Chhattrapati Shivaji Institute of Pharmacy Durg, Chhattisgarh Presented by
- 2. DEFINITION • A Pharmaceutical powder is a mixture of finely divided drugs or chemicals in a dry form meant for internal or external use. • Powder as a dosage form permits drugs to be reduced to a very fine state of division, which often enhances their therapeutic activity or efficacy by an increase of dissolution rate and/or absorption. • A good powder formulation has a uniform particle size distribution. If the particle size distribution is not uniform, the powder can segregate as per to particle size which may result in inaccurate dosing or inconsistent performance.
- 3. Advantages of Powders • Good chemical stability compared with fluids • Useful for bulky drugs with large dose, e.g. indigestion powder. • Easy to swallow even in large bulk, especially if mixed with drink food (useful for stomach- tube feeding) • The smaller particle size of powders causes more rapid dissolution in body fluids, increases drug bioavailability, and decreases gastric irritation compared with tablets
- 4. Disadvantages of Powders • It is undesirable to take bitter or unpleasant tasting drugs by oral administration. • It is difficult to protect powders containing hygroscopic, deliquescent (tending to melt or dissolve in humid environment), or aromatic materials from decomposition. • Chances of error in measurement of dose of powder. • The particle size of a drug influences the rate of solubility in water.
- 5. Reduction of Particle Size The manually operated procedures are trituration, pulverization and levigation. 1- Trituration: It is used to comminute (reduce particle size) & to mix powders. • A porcelin preferred than glass morter. • A glass morter is preferrable for chemicals that stain a porcelin. When granular or crystalline materials are to be incorporated in to powdered product ,these materials are comminuted individually and then blended together in the morter.
- 6. 2-Pulverization • Substance are reduced & subdivided with an additional material ( i.e solvent) that can be removed easily after pulverization is complete. It is used for hard crystalline powders that do not crush or triturate easily, or gummy-type substances. • * This technique is applied to • Substances which are gummy and tend to reagglomerate or which resist grinding. As camphor which is gummy, so addition of alcohol or other volatile solvent can be reduced readily to a fine powder. • Similarly, iodine crystals may be comminuted with the aid of ether. • In both instances the solvent is permitted to evaporate and the powdered material is recovered
- 7. 3- Levigation Levigation is the process of grinding an insoluble substance to a fine powder, while wet. In this process A- paste is first formed by the addition of a suitable non solvent to the solid material. B-Particle-size reduction then accomplished by rubbing the paste in a mortar with a pestle or on an ointment’ slab using a spatula.
- 8. TYPES OF POWDERS 1.Powders for internal use (a) Divided powders (i) Simple powders (ii) Compound powders (iii) Powders enclosed in cachet (iv) Tablet triturates (b) Bulk powders (i) Antacid (ii) Laxative ➢ 2. Powders for external use (a) Dusting powders (i) Medicated dusting powders (ii) Surgical dusting powders (b) insufflations (c) Douche powder (d) Dentifrices 3. Special powders (a) Eutectic mixtures (b) Effervescent powders
- 9. 1.Powders for Internal use/Oral powders • According to Indian Pharmacopoeia 2007, oral powders are finely divided powders that contain one or more medicaments with or without auxiliary substances including, where specified, flavouring and coloring agents. However, addition of saccharin or its salts it not permitted in the preparations meant for pediatric use. • They are intended to be take‘ internally with or without the aid of water or any other suitable liquid. • (a) Divided powders: • Divided powders (or charta) are single doses of powdered drugs individually wrapped in cellophane, metallic foil, or paper.
- 10. • The divided powder is a more accurate dosage form than bulk powder because the patient is not involved in measurement of the dose. • Cellophane and foil-enclosed powders are better protected from the external environment until the time of administration than paper-enclosed powders. • Divided powders are commercially available in foil, cellophane or paper packs. (i) Simple powder: • it consists of only one active ingredient. If powder is in crystalline form, then it is reduced to fine. • Example;- • Aspirin Powder, Calcium Gluconate Powder etc. • Aspirin powder -300 mg • Procedure: Triturate aspirin so as to get fine powder. • Weigh the calculated amount of aspirin powder. Wrap each dose in individual powder paper and pack it.
- 11. (ii) Compound powder: • It consists of mixture of more than one active ingredient and other constituents. • Example: • 1. Aspirin, Paracetamol and Caffeine Powder • Aspirin-300 mg • Paracetamol-150 mg • Caffeine-50 mg • Procedure: • Triturate all the ingredients separately so as to get fine powder. • Weigh the calculated amount of aspirin powder; paracetamol powder and caffeine powder and mix them in ascending order of their weight. • Wrap each dose in individual powder paper.
- 12. (iii) Powders enclosed in cachet: • Cachets consist of a dry powder enclosed in a shell, usually prepared from a mixture of rice flour and water by molding into a suitable shape and drying. • They are quite useful for administering the drugs with nauseating and unpleasant taste and a large dose can be enclosed in a cachet than in a tablet or capsule. • A cachet offers little protection against light -and moisture. • Now-a-days cachets are replaced by capsule. There are two types of catches: Wet 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.
- 13. Dry cachets: • Drug powder is filled in the lower half and the upper half is pressed over it just like a capsule. • 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. • Example:- • Sodium Amino salicylate Cachets, • Sodium Amino salicylate with lsoniazid Cachets.
- 14. (iv) Tablet triturates: • Tablet triturates are powders molded into tablets. • Tablet triturates are generally prepared by mixing the active drug with lactose, dextrose, sucrose, mannitol, or some other appropriate diluents that can serve as the base. • This base must be readily water soluble and should not degrade during the tablet's preparation. • Lactose is the preferred base but mannitol adds a pleasant, cooling sensation and additional sweetness in the mouth
- 15. • Tablet triturates are used for oral administration or sublingual use • (For example, nitroglycerin tablets) • They may also be used in compounding procedures by pharmacists in the preparation of other solid or liquid dosage forms. • They can be inserted into capsules, and this eliminates the problems of measuring the accurate amount of potent drugs in the powder form. • Example: • Propranolol Scopolamine Tablet Triturate; Propranolol hydrochloride 40 mg, Scopolamine hydrobromide 0.5 mg
- 16. (b) Bulk powder • Bulk powders are non-potent and can be closed with acceptable accuracy and safety using measuring devices such as the teaspoon, cup, or insufflators. • The mixed ingredients are packed into a suitable bulk container, such as a wide- mouthed glass jar. Because of the disadvantages of this type of preparation the constituents are usually relatively non-toxic medicaments with a large dose. • This practically limits the use of orally administered bulk Powders to antacids, dietary supplements, laxatives, and a few analgesics.
- 17. (I) Antacid • Example: • Magnesium Trisilicate Oral Powder BP • Magnesium trisilicate-250 mg • Chalk-250 mg • Heavy magnesium carbonate-250 mg • Sodium bicarbonate-250 mg • All powders are sieved using 250 um sieve and mixed well by triturating them in mortar. The final product is packed in amber colored glass jar or plastic container with screw cap. • Use:- For relief of the symptoms of indigestion, heartburn and dyspepsia.
- 18. (ii) Laxative Example: • Polyethylene Glycol 3350 NF Powder for Oral Solution • Polyethylene glycol 3350-13.125 9 • Sodium chloride-350.7 mg • Sodium hydrogen carbonate-178.5 mg • Potassium chloride-46.6 mg • Polyethylene glycol 3350 NF powder for oral solution is an osmotic agent which causes water to be retained with the stool and used for the treatment of constipation. it is supplied in powdered form, for oral administration after dissolution in water, juice, soda, coffee, or tea.
- 19. 2. Powders for external use (a) Dusting powders • Dusting Powders are externally used bulk powders. They are free flowing very fine powders containing antiseptics, antipruritics, astringents, antiperspirants, absorbents, lubricants etc. (i) Medicated dusting powders: • Medicated dusting powders are sterile ones and meant for application on superficial skin. • Body dusting powders have a wide appeal because of smooth feel and cooling effect, which they impart while they temporarily absorb moisture. • The cooling effect is due to extra heat loss due to large surface area of talc particles.
- 20. • Talc-51 g • Kaolin-15g • Precipitated chalk-21g • Zinc stearate-3g • Boric acid-5g • Salicylic acid-5g • Perfume Quantity sufficient • Talc in a major ingredient in medicated dusting powder formulation, which should have good slip characteristics, covering power and body adhesion.
- 21. • In order to improve adhesion properties, metallic stearates such as zinc stearate or magnesium stearate and kaolin are incorporated. • To improve absorbency, magnesium carbonate, starch, kaolin and precipitated chalk are used in combination. • Zinc oxide and titanium dioxide, at low levels along with earth colors can be incorporated and should be sufficiently powerful to cover the base odour. • Other ingredients sometimes included are boric acid to act as skin buffering agent and fused silica to give powder a lower density; salicylic acid for antibacterial action. Aluminum chloride is also incorporated as an antiperspirant
- 22. (ii) Surgical dusting powders: • Surgical dusting powders are intended to be used into deep layer of skin and also on major wounds as a result on burns and umbilical cords of infants. Surgical dusting powders must be free from pathogenic microorganism and hence it must be sterilized before their use. • The dusting powders are mainly used for their antiseptic, astringent, absorbent, antiperspirant, and antipruritic action. • It mainly contains antimicrobial agents like chlorhexidine and hexachlorophene. • They are generally prepared by mixing two or more ingredients one of which must be starch, talc or kaolin as one of the ingredients of the formulation.
- 23. • Talc is more commonly used because of its chemical inertness. • However, since such ingredients are readily contaminated with pathogenic bacteria, these must be sterilized by dry heat method before use. • Dusting powders are dispensed in Sifter-top container or aerosol containers. • It may also be applied with powder puff or sterilized gauze pad.
- 24. Example: • Neosporin Dusting Powder • Bacitracin (5000 IU) • Neomycin (3400 IU) • Polymyxin B (400 IU) • Bacitracin is an antibiotics that acts by inhibiting the growth of bacteria in the wounds. It is used alone or in combination with neomycin and polymyxin to treat and prevent superficial and minor skin infections due to wounds, cuts burns.
- 25. • Neomycin belongs to the class of medications called it antibiotics. it prevents the bacterial growth by stopping the production of essential protein in the bacterial cells, thereby relieving the associated symptoms. • Polymyxin B belongs to a group of medications called as polypeptide antibiotic. It works by killing the bacteria that causes the infection.
- 26. (b) lnsufflations • lnsufflations are medicated dusting powders meant for introduction into the body cavities such as nose, throat, ears, etc. with the help of an apparatus known as insufflators (powder blower). • lt sprays the powder into a stream of finely divided particles all over the site of application. • The 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 gastrointestinal tract. • As like aerosols, uniform dose may not be obtained by insufflations. Examples: • Cromolyn Sodium Powder, • Compound Clioquin Powder USP
- 27. (c) Douche powder • Douche powders are intended to be used as antiseptics or cleansing agents for a body cavity; most commonly for vaginal use, although they may be formulated for nasal, otic or ophthalmic use also. • As douche powder formulation often include aromatic oils. it becomes necessary to pass them through a sieve 40 or 60 to eliminate agglomeration and to ensure complete mixing. • They can be dispensed either in wide mouth glass bottles or in powder boxes but the former are preferred because of protection afforded against air and moisture. • Example: Douche powder • Zinc sulphate Magnesium sulphate • Boric acid • Lemon oil • Purified water
- 28. (d) Dentifrices • Dentifrices are preparations meant to clean the teeth and other parts of oral cavity (gums) using a finger or a toothbrush. • They are available as tooth powder, toothpastes, gels, dental creams and even as dental foams. • They are meant to enhance the personal appearance of the teeth (daily removal of pellicles) by maintaining cleaner teeth.
- 29. • Reduction of bad odour (removal of putrifying food particles from spaces between teeth) and also make the gum healthy. • They contain a suitable detergent or soap, some abrasive substance and a suitable flavour. • The abrasive agents such as calcium sulphate, magnesium carbonate, sodium carbonate and sodium chloride are used in fine powder form. • The main components of tooth powders are solid particles of very fine size and the end product is also a very dry powder.
- 30. • Since the main components like abrasives, surface active agent are solid powders, it is required that they all are in very fine particle size, comminuted, if desired, passed through a sieve and mixed in a mortar in the lab scale and in blenders on an industrial scale. • Hard soap (in fine powder) -50g • Precipitated calcium carbonate -935g • Saccharine sodium -2g • Peppermint oil -4ml • Cinnamon oil -2ml • Methyl salicylate- 8ml • To make-about -1000g
- 31. 3. Special powders (a) Eutectic mixtures: • Eutectic mixtures are defined as mixtures of low melting point ingredients which on mixing together turn to liquid form due to depression in melting point of the mixture below room temperature. • They are mixtures of substances, that liquefy when mixed, rubbed or triturated together. • Examples of the substances which tend to liquefy on mixing are camphor, thymol, menthol, salol. • Any two of these drugs turn to liquid when mixed. • This problem during formulation of powders of such material can be solved by using inert adsorbent such as starch, talc, lactose to prevent dampness of the powder and dispensing the components of the eutectic mixture separately.
- 32. (b) Effervescent powders: • Effervescent powders contain materials which react in presence of water evolving carbon dioxide. • This class of preparations can be supplied either by compounding the ingredients as granules or dispensed in the form of salts. • For evolution of the gas two constituents are essential, a soluble carbonate such as sodium bicarbonate and an organic acid such as citric or tartaric acid. • The preparation can be supplied either as a bulk powder or distributed in individual powders.
- 33. PREPARATION OF POWDERS • Reduction of size • Mixing homogeneously • Geometric dilution • Packaging
- 34. Particle size reduction: • For preparation of powder, each ingredient should be needed in finely ground form; hence manufacturer must use a number of procedures and equipment to reduce the particle size of powder ingredients, this process is called as comminution. • The most common method used for particle size reduction in powder formulation is trituration which involves placing the solid in a mortar and continually grinding the chemical between the mortar and the pestle using a firm, downward pressure. • A small mesh sieve can be used to determine the prevalent particle size of a powder after it has been triturated.
- 35. Preparing a homogenous mixture: • Particle size reduction is followed by homogeneous mixing of all powder ingredients. Many times processes similar to those used for particle size reduction are used for obtaining homogenous mixture. • It is especially effective for mixing small quantities of potent drugs with larger amounts of diluents. Hazardous substances can be effectively mixed by a process called tumbling. • The powders are sealed in zipper-sealed bags or clear bottles with a • lid and tumbled until they are well mixed. • The addition of a coloring agent can assist in determining homogeneity in the mixture. If powders being combined are unequal in quantity, then geometric dilution method is used
- 36. Geometric dilution: • Geometric dilution is the process by which a homogenous mixture or even distribution of two or more substances is achieved. This method is used when potent substances must be mixed with a large amount of diluent. • The potent drug and an approximately equal volume of diluent are placed in a mortar and thoroughly mixed by trituration. • A second portion of diluent, equal in volume to the powder mixture in the mortar is added, and trituration is repeated. • The process is continued; equal volumes of diluent are added to the powder mixture in the mortar until all of the diluent is incorporated. • For example, if dose of potent drug is 120 mg, while mixing entire quantity (120 mg) of potent drug is taken and to it 120 mg of the diluents are added and mix thoroughly. • The resulting 240 mg mixture of potent drug and diluents is again mixed with further 240 mg of diluents and the process is repeated until all the diluents are incorporated
- 37. Packaging of powders: • Bulk powders for external use (sometimes called dusting powders) are often dispensed in a shaker-top container to facilitate topical application. • They may also be dispensed in a wide-mouth jar or a plastic container with a flip-top lid. • The jar or plastic container can be closed tightly to provide increased stability and protection from light and moisture, especially for compounds that contain volatile ingredients. Package should contain label as "For external use only”. • Bulk powders intended for internal use should be dispensed in an amber colored, wide-mouth powder jar with a tight-fitting lid. • They should be accompanied by an appropriately sized dosing spoon or cup and adequate directions for removing and administering a correct dose. • Bulk powders for internal use should be labeled with the strength of the active ingredient per dose (e.g., Potassium chloride 600 mg per tablespoonful).
- 39. Introduction • Weighing is a well-established approach to measuring the weight of an object and involves using a weighing device (e.g., a set of scales) to quantify amounts of ingredients.
- 40. Weighing techniques • Analytical Balance • Double-pan balance • Single-pan balance • Electronic balance
- 41. Analytical balances • Very accurate balances, called analytical balances, are used in scientific fields such as chemistry. • An analytical balance is a class of balance designed to measure small mass in the sub-milligram range.
- 42. Analytical Balance (principal of operation): (i) sample on balance pushes the pan down with a force equal to m x g ➢ M is mass of object ➢ g is acceleration of gravity (ii) balance pan with equal and opposing mass ➢ Mechanical – standard masses ➢ Electronic – opposing electromagnetic force (iii) tare –mass of empty vessel (pan) m1l1 = m2l2 m1 m2 l1 l2 m m
- 43. Single-pan balance • balance beam suspended on a sharp knife edge • Sample pan is balanced by counterweights on right • Knob adjusted to remove weights from a bar above the pan • Pan is moved back to its original position and the removed • weights equals the mass of the sample.
- 44. Double-pan balance • balance beam suspended on a sharp knife edge • Standard weights are added to the second pan to balance sample weight • Weight of sample is equal to the total weight of standards
- 45. Electronic balance • Uses electromagnetic force to return the pan to original position • Electric current required to generate the force is proportional to sample mass. • Very accurate balances, called analytical balances, are used in scientific fields such as chemistry. • An analytical balance is a class of balance designed to measure small mass in the sub-milligram range.
- 46. • Electronic balances are found throughout most laboratories. • They are mostly used to weigh substances and samples between 0.01 to 500 milligrams. • These units’ measuring pans are usually encased in a glass box so as to prevent any dust particles settling in the pan. • An analytical balance measures masses to within 0.0001 g. • Use these balances when you need this high degree of precision.
- 47. Weight Measurements Methods of Weighing: (i) Basic operational rules ➢ Chemicals should never be placed directly on the weighing pan - corrode and damage the pan may affect accuracy - not able to recover all of the sample ➢ Balance should be in arrested position when load/unload pan (ii) Weight by difference: ➢ Useful for samples that change weight upon exposure to the atmosphere - hygroscopic samples (readily absorb water from the air) Weight of sample = ( weight of sample + weight of container) – weight of container (iii) Taring: ➢ Done on many modern electronic balances ➢ Container is set on balance before sample is added ➢ Container’s weight is set automatically to read “0”
- 48. Weight Measurements Errors in Weighing: Sources (i) Any factor that will change the apparent mass of the sample ➢ Dirty or moist sample container - also may contaminate sample ➢ Sample not at room temperature - avoid convection air currents (push/lift pan) ➢ Adsorption of water, etc. from air by sample ➢ Vibrations or wind currents around balance ➢ Non-level balance
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