Pharmaceutical Preparation: Powders and Granules

Powders

• Dry substances made of finely divided particles.
• Serve as medicated powders for both internal and external use.
• Formulated by blending powders with fillers, creating tablets and capsules.
• Can be dissolved or suspended in liquids to make various formulations.
• Incorporated into semisolid bases for ointments and creams.

Particle Size and Analysis

• Key characteristics of particle size: very coarse, coarse, moderately coarse, fine, and very fine.
• Sieves made from durable wire materials are used for sizing.
• Particle size affects bioavailability, suspendability, dose uniformity, penetrability, and tactile properties in formulations.

Methods for Determining Particle Size

• Sieving: Particles are sorted through a series of sieves.
• Microscopy: Utilizes a calibrated grid to assess size.
• Sedimentation Rate: Measures particle settling velocity (Stoke’s Law).
• Light Energy Diffraction: Evaluates light reduction as particles pass through a sensing zone.
• Laser Holography: Involves pulsing a laser through aerosolized particles.
• Cascade Impaction: Sorts particles through varying airstream velocities.

Comminution of Drugs

• Small Scale:
  • Trituration: Grinding substances in a mortar.
  • Levigation: Reducing particle size in ointments and suspensions.
• Large Scale:
  • Mills and Pulverizers: Devices like FitzMill grind particles quickly using rapidly moving blades.

Blending Powders

• Spatulation: Mixing small powder amounts with a spatula.
• Geometric Dilution: Ensures even distribution of potent drugs with diluents.
• Sifting: Produces a light, fluffy blend by passing powders through sifters.
• Tumbling: Involves rotating chambers for mixing.
• Segregation: Separation of powder components due to size and density differences.

Guidelines to Minimize Segregation

• Reduce transfer steps and drop heights.
• Control dust generation and fluidization.
• Use slow fill/transfer rates and appropriate venting.
• Employ deflectors or distributors and optimize hopper design.

Administration Routes

• Internally:
  • Administered orally mixed with water or milk for infants.
  • Can be inhaled for local or systemic effects.
• Externally:
  • Dusted over affected areas using sift-type containers or aerosol.
  • Must be labeled "EXTERNAL USE ONLY."

Advantages of Powders

• Suitable for patients struggling to swallow tablets or capsules.
• Useful when drugs are too bulky for tablet formation.
• Facilitate faster absorption due to larger surface area compared to solid forms.

Powders

• Dry substances made of finely divided particles.
• Serve as medicated powders for both internal and external use.
• Formulated by blending powders with fillers, creating tablets and capsules.
• Can be dissolved or suspended in liquids to make various formulations.
• Incorporated into semisolid bases for ointments and creams.

Particle Size and Analysis

• Key characteristics of particle size: very coarse, coarse, moderately coarse, fine, and very fine.
• Sieves made from durable wire materials are used for sizing.
• Particle size affects bioavailability, suspendability, dose uniformity, penetrability, and tactile properties in formulations.

Methods for Determining Particle Size

• Sieving: Particles are sorted through a series of sieves.
• Microscopy: Utilizes a calibrated grid to assess size.
• Sedimentation Rate: Measures particle settling velocity (Stoke’s Law).
• Light Energy Diffraction: Evaluates light reduction as particles pass through a sensing zone.
• Laser Holography: Involves pulsing a laser through aerosolized particles.
• Cascade Impaction: Sorts particles through varying airstream velocities.

Comminution of Drugs

• Small Scale:
  • Trituration: Grinding substances in a mortar.
  • Levigation: Reducing particle size in ointments and suspensions.
• Large Scale:
  • Mills and Pulverizers: Devices like FitzMill grind particles quickly using rapidly moving blades.

Blending Powders

• Spatulation: Mixing small powder amounts with a spatula.
• Geometric Dilution: Ensures even distribution of potent drugs with diluents.
• Sifting: Produces a light, fluffy blend by passing powders through sifters.
• Tumbling: Involves rotating chambers for mixing.
• Segregation: Separation of powder components due to size and density differences.

Guidelines to Minimize Segregation

• Reduce transfer steps and drop heights.
• Control dust generation and fluidization.
• Use slow fill/transfer rates and appropriate venting.
• Employ deflectors or distributors and optimize hopper design.

Administration Routes

• Internally:
  • Administered orally mixed with water or milk for infants.
  • Can be inhaled for local or systemic effects.
• Externally:
  • Dusted over affected areas using sift-type containers or aerosol.
  • Must be labeled "EXTERNAL USE ONLY."

Advantages of Powders

• Suitable for patients struggling to swallow tablets or capsules.
• Useful when drugs are too bulky for tablet formation.
• Facilitate faster absorption due to larger surface area compared to solid forms.

Explore the essential characteristics of powders and granules in pharmaceutical preparations. This quiz covers the physical properties, types, and usage of medicated powders, highlighting their role in both internal and external applications. Test your knowledge on this vital topic in pharmacy.