Podcast
Questions and Answers
What is the primary distinction between a powder and a granule in pharmaceutical dosage forms?
What is the primary distinction between a powder and a granule in pharmaceutical dosage forms?
- A powder consists of finely divided particles, while a granule consists of aggregated powder particles. (correct)
- A powder is intended for internal use, while a granule is for external use.
- A powder is smaller in particle size than a granule, typically less than 1 mm.
- A powder is always medicated, while a granule is always non-medicated.
Which of the following is a reason why powders might be favored over standardized capsules or tablets?
Which of the following is a reason why powders might be favored over standardized capsules or tablets?
- Powders have a longer shelf life than tablets or capsules.
- Powders are easier to administer to all patient populations.
- Powders allow for easier adjustment of medication quantity for each dose. (correct)
- Powders are always less expensive to produce.
Why do powders generally exhibit a more rapid onset of action compared to tablets and capsules?
Why do powders generally exhibit a more rapid onset of action compared to tablets and capsules?
- Powders contain more potent active ingredients.
- Powders are directly absorbed into the bloodstream.
- Powders bypass the need for dissolution.
- Powders have a larger surface area and only require dissolution, not disintegration, before absorption. (correct)
According to the USP, which sieve number designates a 'coarse' powder?
According to the USP, which sieve number designates a 'coarse' powder?
What is the primary purpose of micronizing a drug powder?
What is the primary purpose of micronizing a drug powder?
Which particle size range is generally considered suitable for inhalation, allowing deposition deep within the respiratory tract?
Which particle size range is generally considered suitable for inhalation, allowing deposition deep within the respiratory tract?
What does a high angle of repose generally indicate about a powder?
What does a high angle of repose generally indicate about a powder?
In what size range do particles generally flow freely, assuming they have an amenable shape?
In what size range do particles generally flow freely, assuming they have an amenable shape?
What is the term for reducing the particle size of a solid substance to a finer state?
What is the term for reducing the particle size of a solid substance to a finer state?
Which method of particle size reduction involves creating a paste with a liquid in which the powder is insoluble?
Which method of particle size reduction involves creating a paste with a liquid in which the powder is insoluble?
What is the purpose of pulverization by intervention?
What is the purpose of pulverization by intervention?
Why is freeze-drying (lyophilization) used in the preparation of some pharmaceutical powders?
Why is freeze-drying (lyophilization) used in the preparation of some pharmaceutical powders?
Which powder blending method is best suited for mixing eutectic mixtures?
Which powder blending method is best suited for mixing eutectic mixtures?
What is geometric dilution primarily used for in powder blending?
What is geometric dilution primarily used for in powder blending?
Which of the following blending methods is least suitable for incorporating potent drugs into a diluent powder?
Which of the following blending methods is least suitable for incorporating potent drugs into a diluent powder?
What is 'segregation' in the context of powder mixtures, and why is it undesirable?
What is 'segregation' in the context of powder mixtures, and why is it undesirable?
Which of the following is NOT a general guideline to minimize or prevent powder segregation?
Which of the following is NOT a general guideline to minimize or prevent powder segregation?
What is a primary disadvantage of using oral powders for systemic effects?
What is a primary disadvantage of using oral powders for systemic effects?
What particle size range is generally required for medicated powders administered via dry powder inhalers (DPIs) to reach deep into the lungs?
What particle size range is generally required for medicated powders administered via dry powder inhalers (DPIs) to reach deep into the lungs?
What should medicated powders for external use always indicate on their label?
What should medicated powders for external use always indicate on their label?
When dispensing powder medication in bulk quantities, what type of substances should it be limited to?
When dispensing powder medication in bulk quantities, what type of substances should it be limited to?
What type of powder paper should be used if the powder contains hygroscopic or deliquescent materials?
What type of powder paper should be used if the powder contains hygroscopic or deliquescent materials?
What issue is addressed by granulating mixed powders?
What issue is addressed by granulating mixed powders?
What is the typical mesh size range for granules intended for pharmaceutical use?
What is the typical mesh size range for granules intended for pharmaceutical use?
Which of the following is an advantage of granules over powders?
Which of the following is an advantage of granules over powders?
Why are granules often preferred over powders for the preparation of solutions?
Why are granules often preferred over powders for the preparation of solutions?
What is a common method used in dry granulation?
What is a common method used in dry granulation?
In the context of effervescent granules, why is a combination of citric and tartaric acids preferred over using either acid alone?
In the context of effervescent granules, why is a combination of citric and tartaric acids preferred over using either acid alone?
What is the typical ratio of citric acid to tartaric acid in a good effervescent blend?
What is the typical ratio of citric acid to tartaric acid in a good effervescent blend?
In the fusion method of preparing effervescent granules, what acts as the binding agent for the powder mixture?
In the fusion method of preparing effervescent granules, what acts as the binding agent for the powder mixture?
During the preparation of effervescent granules using the fusion method, at what temperature range is the powder typically heated?
During the preparation of effervescent granules using the fusion method, at what temperature range is the powder typically heated?
What is the primary difference between the wet method and the fusion method of preparing effervescent granules?
What is the primary difference between the wet method and the fusion method of preparing effervescent granules?
A pharmacist receives a prescription for a divided powder containing a potent drug. Which method should the pharmacist use to ensure accurate dosing?
A pharmacist receives a prescription for a divided powder containing a potent drug. Which method should the pharmacist use to ensure accurate dosing?
A pharmaceutical company is developing an inhalation powder for a new drug. During formulation, they notice significant variability in the emitted dose from their dry powder inhaler (DPI). Which formulation change is MOST likely to improve the dose uniformity?
A pharmaceutical company is developing an inhalation powder for a new drug. During formulation, they notice significant variability in the emitted dose from their dry powder inhaler (DPI). Which formulation change is MOST likely to improve the dose uniformity?
During the scale-up of an effervescent tablet manufacturing process, engineers observe that the tablets are exhibiting 'capping' (separation of the top layer) after compression. Given the effervescent nature of the formulation, which adjustment to the process is LEAST likely to resolve this issue?
During the scale-up of an effervescent tablet manufacturing process, engineers observe that the tablets are exhibiting 'capping' (separation of the top layer) after compression. Given the effervescent nature of the formulation, which adjustment to the process is LEAST likely to resolve this issue?
A pharmacist is compounding a topical powder containing a potent corticosteroid. The formula includes starch as a diluent. After mixing, the pharmacist notices that the powder has a slightly 'musty' odor and suspecting microbial contamination, sends a sample for analysis. The results confirm the presence of Bacillus cereus. Knowing that Bacillus cereus can hydrolyze starch, what is the MOST concerning potential consequence for the patient if this contaminated powder is dispensed?
A pharmacist is compounding a topical powder containing a potent corticosteroid. The formula includes starch as a diluent. After mixing, the pharmacist notices that the powder has a slightly 'musty' odor and suspecting microbial contamination, sends a sample for analysis. The results confirm the presence of Bacillus cereus. Knowing that Bacillus cereus can hydrolyze starch, what is the MOST concerning potential consequence for the patient if this contaminated powder is dispensed?
A pharmaceutical scientist is designing a novel dry powder inhaler (DPI) formulation for pulmonary delivery of a peptide drug. The peptide is known to be susceptible to enzymatic degradation in the lungs. Which strategy would be the MOST effective in maximizing drug bioavailability and minimizing enzymatic degradation in the lung environment immediately after inhalation?
A pharmaceutical scientist is designing a novel dry powder inhaler (DPI) formulation for pulmonary delivery of a peptide drug. The peptide is known to be susceptible to enzymatic degradation in the lungs. Which strategy would be the MOST effective in maximizing drug bioavailability and minimizing enzymatic degradation in the lung environment immediately after inhalation?
A pharmacist is preparing divided powders using the block-and-divide method. After creating a uniform block of powder, it is noted that the individual doses appear to have some variation in weight. What is the MOST likely reason for this?
A pharmacist is preparing divided powders using the block-and-divide method. After creating a uniform block of powder, it is noted that the individual doses appear to have some variation in weight. What is the MOST likely reason for this?
What is the typical size range for granules used as a dosage form?
What is the typical size range for granules used as a dosage form?
Which patient population often benefits most from powder dosage forms due to ease of administration?
Which patient population often benefits most from powder dosage forms due to ease of administration?
What is a key reason powders might be chosen when developing drugs for clinical studies?
What is a key reason powders might be chosen when developing drugs for clinical studies?
Which of the following solid dosage forms is manufactured using powdered drugs blended with other powdered pharmaceutical ingredients?
Which of the following solid dosage forms is manufactured using powdered drugs blended with other powdered pharmaceutical ingredients?
According to the USP, what particle size designation is assigned to a powder if all particles pass through a No. 40 sieve and not more than 40% pass through a No. 80 sieve?
According to the USP, what particle size designation is assigned to a powder if all particles pass through a No. 40 sieve and not more than 40% pass through a No. 80 sieve?
What particle size range is generally optimal for powders intended for inhalation and deposition deep within the respiratory tract?
What particle size range is generally optimal for powders intended for inhalation and deposition deep within the respiratory tract?
What property does the angle of repose primarily indicate about a powder?
What property does the angle of repose primarily indicate about a powder?
What is the primary purpose of comminution in pharmaceutical compounding?
What is the primary purpose of comminution in pharmaceutical compounding?
What is the MOST important reason for controlling particle size in pharmaceutical powders?
What is the MOST important reason for controlling particle size in pharmaceutical powders?
A powder has a cone height of 4.0 cm and a cone diameter of 10 cm after flowing through a funnel. What is its approximate angle of repose?
A powder has a cone height of 4.0 cm and a cone diameter of 10 cm after flowing through a funnel. What is its approximate angle of repose?
Which of these methods for particle size reduction involves creating a paste with a liquid in which the powder is insoluble?
Which of these methods for particle size reduction involves creating a paste with a liquid in which the powder is insoluble?
Why is geometric dilution used when blending powders?
Why is geometric dilution used when blending powders?
Which powder blending method is LEAST suitable for incorporating potent drugs into a large quantity of diluent powder?
Which powder blending method is LEAST suitable for incorporating potent drugs into a large quantity of diluent powder?
What is a common problem in powder mixtures caused by differences in the size and density of the particles?
What is a common problem in powder mixtures caused by differences in the size and density of the particles?
What is a key recommendation to PREVENT powder segregation during handling and processing?
What is a key recommendation to PREVENT powder segregation during handling and processing?
Why are some oral medications prepared as dry powders or granules for reconstitution?
Why are some oral medications prepared as dry powders or granules for reconstitution?
What is the recommended storage condition for all powders and granules to prevent deterioration?
What is the recommended storage condition for all powders and granules to prevent deterioration?
What particle size is generally targeted for medicated powders administered via dry powder inhalers (DPIs)?
What particle size is generally targeted for medicated powders administered via dry powder inhalers (DPIs)?
What specific instruction should always be included on the label of medicated powders intended for external use?
What specific instruction should always be included on the label of medicated powders intended for external use?
Dispensing powder medication in bulk quantities is generally limited to which type of substances?
Dispensing powder medication in bulk quantities is generally limited to which type of substances?
Which type of powder paper is MOST suitable for containing hygroscopic materials?
Which type of powder paper is MOST suitable for containing hygroscopic materials?
What is a PRIMARY motivation for granulating powders in pharmaceutical manufacturing?
What is a PRIMARY motivation for granulating powders in pharmaceutical manufacturing?
What is an advantage of formulating a drug as granules compared to a powder?
What is an advantage of formulating a drug as granules compared to a powder?
In the wet method of preparing granules, after moistening the powder or powder mixture, what is the next step?
In the wet method of preparing granules, after moistening the powder or powder mixture, what is the next step?
In the context of effervescent granules, what is the primary purpose of using a combination of citric and tartaric acids?
In the context of effervescent granules, what is the primary purpose of using a combination of citric and tartaric acids?
What is the typical ratio of citric acid to tartaric acid in a well-formulated effervescent granule blend?
What is the typical ratio of citric acid to tartaric acid in a well-formulated effervescent granule blend?
In the fusion method of preparing effervescent granules, what component acts as the binding agent for the powder mixture?
In the fusion method of preparing effervescent granules, what component acts as the binding agent for the powder mixture?
During the fusion method of effervescent granule preparation, what is the typical temperature range used for heating the powder mixture?
During the fusion method of effervescent granule preparation, what is the typical temperature range used for heating the powder mixture?
What distinguishes the wet method from the fusion method in effervescent granule preparation?
What distinguishes the wet method from the fusion method in effervescent granule preparation?
A pharmaceutical company is reformulating an existing immediate-release tablet into a powder form to improve drug absorption. After pre-formulation studies, they discover the drug is highly hydrophobic and poorly wetted by gastric fluids. Which excipient would MOST likely enhance the drug's dissolution rate in this new powder formulation?
A pharmaceutical company is reformulating an existing immediate-release tablet into a powder form to improve drug absorption. After pre-formulation studies, they discover the drug is highly hydrophobic and poorly wetted by gastric fluids. Which excipient would MOST likely enhance the drug's dissolution rate in this new powder formulation?
A pharmacist is preparing divided powders containing a hygroscopic drug in a high-humidity environment. Despite using waxed paper, the powders are still clumping. What additional measure would BEST protect the powders from moisture?
A pharmacist is preparing divided powders containing a hygroscopic drug in a high-humidity environment. Despite using waxed paper, the powders are still clumping. What additional measure would BEST protect the powders from moisture?
During the development of an effervescent granule formulation, the scientists observe that the granules are producing excessive fizzing action upon contact with water resulting in, significant product loss due to overflow. Which modification to the formulation or manufacturing process would MOST effectively reduce the fizzing intensity without compromising effervescence?
During the development of an effervescent granule formulation, the scientists observe that the granules are producing excessive fizzing action upon contact with water resulting in, significant product loss due to overflow. Which modification to the formulation or manufacturing process would MOST effectively reduce the fizzing intensity without compromising effervescence?
A research pharmacist is developing a novel powder formulation for pulmonary delivery of a protein drug using a dry powder inhaler (DPI). The protein has poor flow properties, causing inconsistent dosing. Which excipient strategy would MOST likely improve the powder's flowability and dose uniformity without compromising the protein's integrity?
A research pharmacist is developing a novel powder formulation for pulmonary delivery of a protein drug using a dry powder inhaler (DPI). The protein has poor flow properties, causing inconsistent dosing. Which excipient strategy would MOST likely improve the powder's flowability and dose uniformity without compromising the protein's integrity?
A compounding pharmacist receives a prescription for a divided powder containing an extremely potent and light-sensitive drug. The pharmacist wants to ensure maximum accuracy and stability. Which of the following techniques would be MOST appropriate?
A compounding pharmacist receives a prescription for a divided powder containing an extremely potent and light-sensitive drug. The pharmacist wants to ensure maximum accuracy and stability. Which of the following techniques would be MOST appropriate?
A formulation scientist is working with a novel drug that is extremely sensitive to heat and moisture. They need to create a stable powder formulation for oral administration. Which particle size reduction and drying method would be MOST appropriate to maintain the drug's integrity?
A formulation scientist is working with a novel drug that is extremely sensitive to heat and moisture. They need to create a stable powder formulation for oral administration. Which particle size reduction and drying method would be MOST appropriate to maintain the drug's integrity?
A novel excipient is added to a powder formulation, and it is observed that the angle of repose decreases significantly. Which of the following is the LEAST likely explanation considering the altered behavior?
A novel excipient is added to a powder formulation, and it is observed that the angle of repose decreases significantly. Which of the following is the LEAST likely explanation considering the altered behavior?
A very potent drug is being formulated into a powder for reconstitution, specifically for pediatric patients, and requires an exact dose. Which approach would achieve this MOST safely and accurately?
A very potent drug is being formulated into a powder for reconstitution, specifically for pediatric patients, and requires an exact dose. Which approach would achieve this MOST safely and accurately?
An investigator is using spray drying to create microparticles from a protein solution for lung delivery. The protein has a tendency to denature during the process. What strategy may BEST prevent the denaturation?
An investigator is using spray drying to create microparticles from a protein solution for lung delivery. The protein has a tendency to denature during the process. What strategy may BEST prevent the denaturation?
Which particle size range is generally targeted for medicated powders administered via dry powder inhalers (DPIs) to ensure effective deposition deep within the lungs?
Which particle size range is generally targeted for medicated powders administered via dry powder inhalers (DPIs) to ensure effective deposition deep within the lungs?
A pharmacist is compounding a powder formulation containing multiple active pharmaceutical ingredients (APIs) with varying densities. What is the MOST effective method to ensure uniform distribution of the APIs and prevent segregation?
A pharmacist is compounding a powder formulation containing multiple active pharmaceutical ingredients (APIs) with varying densities. What is the MOST effective method to ensure uniform distribution of the APIs and prevent segregation?
In the context of powder blending, what phenomenon describes the separation of powder mixture components due to differences in size and density, often resulting in a non-uniform product?
In the context of powder blending, what phenomenon describes the separation of powder mixture components due to differences in size and density, often resulting in a non-uniform product?
During the preparation of effervescent granules using the fusion method, the powder mixture is heated to facilitate the release of water from citric acid monohydrate. Which consequence would MOST likely arise if the heating temperature drastically exceeds the recommended range of 34°C to 40°C?
During the preparation of effervescent granules using the fusion method, the powder mixture is heated to facilitate the release of water from citric acid monohydrate. Which consequence would MOST likely arise if the heating temperature drastically exceeds the recommended range of 34°C to 40°C?
An advanced drug delivery system is being designed which involves encapsulating nanoparticles containing an unstable protein drug within a micronized powder intended for pulmonary inhalation. It is observed that during the spray drying process, the protein undergoes significant denaturation, compromising its therapeutic activity. Which modification to the spray drying process is LEAST likely to mitigate this issue?
An advanced drug delivery system is being designed which involves encapsulating nanoparticles containing an unstable protein drug within a micronized powder intended for pulmonary inhalation. It is observed that during the spray drying process, the protein undergoes significant denaturation, compromising its therapeutic activity. Which modification to the spray drying process is LEAST likely to mitigate this issue?
Flashcards
Powder
Powder
A dry substance composed of finely divided particles. Also, a medicated preparation for internal or external use.
Granules
Granules
Aggregates of powder particles, typically 2-4 mm in diameter.
Advantages of powders
Advantages of powders
Enables altering medication quantity per dose, aids clinical studies, suitable for those who can't swallow pills, Used for bulky drugs, provides rapid action.
Geometric dilution
Geometric dilution
Method to ensure uniform distribution of a potent drug by diluting it with an inert substance in stepwise fashion
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Micromeritics
Micromeritics
The science of small particles.
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Angle of repose
Angle of repose
Estimates powder flow properties by measuring the angle formed when powder flows through a funnel onto a surface.
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Comminution
Comminution
The reduction of particle size of a solid substance to a finer state.
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Trituration
Trituration
Grinding a drug in a mortar to reduce its particle size.
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Levigation
Levigation
Reduces particle size by combining a powder with a levigating agent to form a paste, then triturating.
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Pulverization by intervention
Pulverization by intervention
Reduces particle size with the aid of a second agent, which can readily remove from the pulverized product.
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Spatulation
Spatulation
Blending small amounts of powders using a spatula on paper or an ointment tile.
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Segregation
Segregation
Undesirable separation of powder mixture components due to differences in density and size.
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Dry Powder Inhalers (DPIs)
Dry Powder Inhalers (DPIs)
Delivers micronized medication in metered quantities for inhalation.
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Bulk powders
Bulk powders
Powders mixed with water or beverages before swallowing.
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Divided powders
Divided powders
Individual dosing units of powder, each enclosed in a folded paper or packet.
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Weighing method
Weighing method
Weighing each portion of powder separately before enfolding it in a paper.
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Block-and-divide method
Block-and-divide method
Approximate each portion by dividing the entire amount of the prepared powder on a flat surface
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Granules
Granules
Aggregates of powder particles to form larger, more robust particles.
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Advantages of granulation
Advantages of granulation
Increase flow, increase compressibility, smaller surface area, and are more easily wetted by a solvent.
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Effervescent dosage form
Effervescent dosage form
Ingredients release carbon dioxide upon contact with water, creating effervescence.
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Wet method for granules
Wet method for granules
Powder is moistened; paste is passed through a screen; granules are dried.
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Dry method for granules
Dry method for granules
Dry powder is compacted or compressed; slugs are granulated.
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Fusion method
Fusion method
Water present in citric acid acts as a binding agent for the powder mixture.
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Wet method: Effervescent granules
Wet method: Effervescent granules
All of the powders may be anhydrous as long as water is added to the moistening liquid
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Powders
- Powders are solid, dry substances composed of finely divided particles.
- Powders can be medicated for internal (oral) or external (topical) use.
- Granules are powder particles aggregated into larger particles, usually 2-4 mm in diameter.
Advantages of Powders
- Allows for easy alteration of medication quantity per dose.
- Facilitates dose adjustments in clinical studies.
- Enables individual weighing and packaging of doses.
- Suitable for infants and young children who cannot swallow solid dosage forms, by mixing with food/formula.
- Effective for drugs too bulky for capsules or tablets.
- Provides rapid onset of action due to easy dispersion, large surface area, and only requiring dissolution before absorption.
Use of Powders
- Powders are used in the preparation of other dosage forms (tablets, capsules, liquid dosage forms, ointments, and creams).
Physicochemical Considerations
- Solid materials must be characterized for their morphology, purity, solubility, flowability, stability, particle size, uniformity, and compatibility before use in pharmaceutical products.
Particle Size
- Particle size adjustment ensures efficient production and optimum therapeutic efficacy.
- Particle sizes range from extremely coarse (10 mm) to extremely fine (1 μm or less).
- The USP uses descriptive terms for particle size: very coarse, coarse, moderately coarse, fine, and very fine
Sieve Sizes
- Very coarse (No. 8): All particles pass through a No. 8 sieve, and not more than 20% pass through a No. 60 sieve.
- Coarse (No. 20): All particles pass through a No. 20 sieve, and not more than 40% pass through a No. 60 sieve.
- Moderately coarse (No. 40): All particles pass through a No. 40 sieve, and not more than 40% pass through a No. 80 sieve.
- Fine (No. 60): All particles pass through a No. 60 sieve, and not more than 40% pass through a No. 100 sieve.
- Very fine (No. 80): All particles pass through a No. 80 sieve, with no limit to greater fineness.
Factors Influenced by Particle Size
- Dissolution rate: Drug micronization increases dissolution and bioavailability.
- Suspendability: Fine dispersions (~0.5 to 10 μm) ensure uniform distribution in liquid vehicles.
- Uniform Distribution: Ensures dose-to-dose content uniformity.
- Penetrability: Particles intended for inhalation (1 to 5 μm) reach deep into the respiratory tract.
- Lack of Grittiness: Fine powders (50 to 100 μm) prevent grittiness in dermal and ophthalmic preparations.
Micromeritics
- Micromeritics is the science of small particles.
- Micromeritics studies particle size, size distribution, shape, angle of repose, porosity, true volume, bulk volume, apparent density, and bulkiness.
Angle of Repose
- Angle of repose estimates the flow properties of a powder.
- Calculated using the formula: tan θ = h/r, where h is the height and r is the radius of the powder cone.
- Powders with a low angle of repose flow freely; high angles indicate poor flow.
Flowability Factors
- Shape: Spherical particles flow better than needles.
- Size: Very fine particles flow less freely than large particles.
- Particles in the 250 to 2,000 μm range flow freely if the shape is amenable.
- Particles in the 75 to 250 μm range may flow freely or cause problems.
- Particles smaller than 100 μm usually have flow issues.
Particle Size Reduction
- Comminution reduces particle size to facilitate crude drug extraction, increase dissolution rates, aid in dosage form formulation, and enhance drug absorption.
- Reduces particle size increases the substance's specific surface area.
Manual Methods of Comminution
- Trituration: Grinding a drug in a mortar to reduce its particle size.
- Levigation: Reducing particle size by forming a paste with a liquid (levigating agent) in which the powder is insoluble.
- Pulverization by intervention: Reducing particle size with the aid of a second agent that can be removed from the pulverized product.
Special Particle Size Reduction Processes
- Freeze Drying (Lyophilization): Removing water by sublimation from frozen products at low temperatures (-10 to -40°C), used for heat-labile biological products.
- Spray Drying: Converting solutions or suspensions into dry, free-flowing powders by atomizing the liquid into a chamber with heated air.
Blending Powders
- Reduce particle size of each powder individually before blending to ensure a uniform mixture.
- Powders can be blended by spatulation, trituration, sifting, and tumbling.
Spatulation
- Blending small amounts of powders using a spatula on paper or an ointment tile.
- Not suitable for large quantities or potent substances.
- Useful for mixing eutectic mixtures with an inert diluent to minimize contact.
Trituration
- Used to both triturate and mix powders, using a glass mortar for simple mixing.
- Geometric dilution ensures uniform distribution of a potent substance with a large amount of diluent.
Sifting (Sieving)
- Mixing powders by passing them through sifters.
- Results in a light, fluffy product.
- Not suitable for incorporating potent drugs into a diluent powder.
Tumbling
- Mixing powders in a rotating chamber.
- Thorough but time-consuming.
Problems with Particle Size Reduction
- Segregation: Undesirable separation of powder mixture components due to differences in density and size.
Types of Segregation
- Sifting or Percolation: Fine particles sift through coarse particles and end up at the bottom.
- Air Entrapment (Fluidization): Fine, aerated powders create striation patterns during transfer.
- Particle Entrapment (Dusting): Finer, lighter particles remain suspended in air longer.
Guidelines to Minimize Segregation
- Minimize transfer steps and drop heights.
- Control dust generation and fluidization of powder.
- Use a slow fill/transfer rate.
- Ensure appropriate venting.
- Use a deflector, vane, or distributor.
- Proper hopper design and operating valves.
Medicated Powders
- Medicated powders can be for internal or external use.
Internal Powders
- Usually taken orally after mixing with water.
- Some are inhaled, others reconstituted with a liquid solvent for oral administration, injection, or vaginal douche.
Medicated Powders for Oral Use
- May have local (e.g., laxatives) or systemic effects (e.g., analgesics).
- Suitable for patients who have difficulty swallowing solid dosage forms.
- May result in faster dissolution and absorption than solid dosage forms.
Aerosol Powders
- Administered by inhalation using dry powder inhalers (DPIs).
- Used for asthma and bronchial disorders.
- Micronized medication particle size is 1 to 6 μm.
Nasal Powders
- Intended for inhalation into the nasal cavity.
- Rapidly absorbed when administered as a fine powder.
External Powders
- Dusted on the affected area from a sifter-type container or powder aerosol.
- Labeled “EXTERNAL USE ONLY.”
- Should be free from grittiness.
- Sterile powders are required for large open wounds or severely injured skin.
- Intended for therapeutic, prophylactic or lubricant purposes
Dispensing of Powders
- Medicated powders can be provided in bulk or divided into unit-of-use packages.
- Some powders are pre-packaged, others are prepared and packaged by the pharmacist.
Bulk Powders
- Include antacids, laxatives, douche powders, medicated powders for the skin, and nutritional supplements.
- Dispensing is limited to non-potent substances.
- Requires patient education on handling, storage, measurement, and preparation.
- Should be stored at room temperature in a clean, dry place, out of reach of children.
Divided Powders
- Powders are divided into individual dosing units after proper blending.
- Each portion is placed on a paper (chartula).
- The smallest amount of powders in a packet is 130mg
Methods for preparing divided powders
- Weighing method: weigh each portion of powder separately before enfolding in a paper (for potent drugs).
- Block-and-divide method: approximate each portion by using the block-and- divide method, used only for non-potent drugs.
Powder Papers
- The powder papers may be of any size convenient to hold the amount of powder required
- Papers include simple bond paper, vegetable parchment, glassine, and waxed paper.
- Paper type is selected based on the powder's nature.
- Waterproof or waxed paper should be used for hygroscopic or deliquescent materials.
Granules Dosage Forms
- Granulation prevents segregation of ingredients due to particle size differences.
- Granules are aggregates of powder particles, typically in the 4-12 mesh size range.
Advantages of Granulation
- Granules flow better than powders, improving drug material supply to tableting presses.
- Granules increase compressibility.
- Granules have a smaller surface area, making them more stable physically and chemically.
- Granules are less likely to cake or harden upon standing.
- Granules are more easily wetted by a solvent than powders.
- Granules produce particle-size uniformity, thus content uniformity.
Examples of Granules
- Antibiotic drugs unstable in aqueous solution are prepared as granules for reconstitution with purified water.
- Granules contain medicinal agents, colorants, flavorants, and other pharmaceutical ingredients.
Preparation of Granules
- Granules are prepared by wet methods and dry methods.
Wet Methods
- Moisten the powder with a fluid, pass the paste through a screen, and dry the granules.
- An alternative wet method is fluid bed processing, in which particles are placed in a conical piece of equipment and are vigorously dispersed and suspended while a liquid excipient is sprayed to the particles and dried.
Dry Methods
- Pass the dry powder through a roll compactor and then through a granulating machine.
- Slugging: Compress a powder into large tablets or slugs and then granulate into the desired particle size.
Effervescent Granulated Salts
- Contain ingredients that release carbon dioxide when in contact with water.
- Masks the undesirable taste of medicinal agents.
- Consist of sodium bicarbonate, citric acid, and tartaric acid.
Combination of Acids
- Using a combination of citric and tartaric acids avoids issues of firmness loss and stickiness.
- A good effervescent blend consists of both citric acid and tartaric acid (1:2 ratio).
- The ratio of the effervescent ingredients is 1:2:3.4 for the citric acid: tartaric acid: sodium bicarbonate.
Methods for Preparing Effervescent Granules
- Fusion (dry) method and wet method.
Fusion Method
- The water in citric acid acts as the binding agent.
- Mix powders rapidly in a low humidity environment.
- Heat the powder to release water of crystallization, then rub through a sieve to produce granules.
Wet Method
- Water is added to alcohol as the moistening agent to form a pliable mass for granulation.
- Prepare granules and dry them in the same manner as the fusion method.
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