part 2: POWDERS

Powders

Mixture of finely divided drugs or chemicals in dry form which can be used internally or externally

Oral powders

Powders that are used internally are called what?

Topical powders

Powders that are used externally are called what?

1. Flexibility of compounding

2. Good chemical stability

3. Rapid dispersion

Advantages of Powders

1. Time consuming preparation

2. Inaccuracy of dose

3. Unsuitability for unpleasant tasting, hygroscopic, and deliquescent drugs

Disadvantages of Powders

1. Very Coarse

2. Coarse

3. Moderately Coarse

4. Fine

5. Very Fine

The USP describes powder in terms such ____________, ____________, ___________, __________, and __________

#8

Sieve number of Very Course Animal and Vegetable Drugs

#20

Sieve number of Course Animal and Vegetable Drugs

#40

Sieve number of Moderately Course Animal and Vegetable Drugs

#60

Sieve number of Fine Animal and Vegetable Drugs

#80

Sieve number of Very Fine Animal and Vegetable Drugs

#20

Sieve number of Course Chemical

#40

Sieve number of Moderately Course Chemical

#80

Sieve number of Fine Chemical

#120

Sieve number of Very Fine Chemical

1. Comminution

2. Mixing or Blending

Compounding of Powders are done by what processes?

Comminution

• Reduction of the particle size of a solid substance to a finer state

• On small scale, the pharmacist usually uses one of the following comminution techniques

  • Trituration

  • Levigation

  • Pulverization by Intervention

Trituration

Reduction of particle size with use of Mortar and Pestle

Mortar and Pestle

Most frequently used utensils in small scale comminution

1. Glass

2. Wedgewood

3. Porcelain

Different types of Mortar

Glass

Type of Mortar that has a smooth surface and non-porous appearance

Wedgewood

Type of Mortar that has a rough surface and porous appearance

Porcelain

Type of Mortar that has a rough surface and less porous appearance

Glass

Type of Mortar that is used for Highly colored materials and dyes

Wedgewood

Type of Mortar that is used for Crystalline solids

Porcelain

Type of Mortar that is used for Soft aggregates or Crystals

Levigation

• Formation of Paste by adding Levigating agents

• Often used to prevent grittiness of solids incorporated in dermatologic or ophthalmic ointment and suspension

1. Mineral Oil

2. Glycerin

Examples of Levigating agents

8 track

Commonly used to incorporate materials (Levigating agents)

Pulverization by Intervention

Addition of volatile substances to a gummy substance that deagglomerate or resist grinding, the solvent is then permitted to evaporate

Alcohol

Solvent used in pulverizing Camphor

Ether

Solvent used in pulverizing Iodine crystals

Mixing or Blending

• Process of mixing powders to produce a uniform mixture

• Powders are mixed, or blended, by the following five methods

  • Spatulation

  • Trituration

  • Geometric Dilution

  • Sifting

  • Tumbling

Spatulation

This method is adequate for mixing:

• Small amounts of powders

• Same densities of powders

• Solid substances that liquefy or form Eutectic Mixture

Spatula

Is used to blend small amounts of powders on a sheet of paper or a pill tile

Trituration

Involves direct rubbing or grinding of hard powder in a Mortar and Pestle

Glass

Type of Mortar used for Simple admixture and colored substances

Wedgewood

Type of Mortar used in Pulverization and Grinding

Geometric Dilution

• Addition of equal volume of diluent to potent substances

• (+) inert colored powder to the diluent before mixing

Sifting

• Powders are mixed by passing them through sifters similar to those used to sift flour

• This process results in a light, fluffy product

• This method is:

  • Helpful for powders that resist mixing by Trituration

  • Allows removal of Agglomerates from the powder mix

  • Not used for Potent substances

• Best for Light powders

1. Magnesium oxide

2. Charcoal

Examples of Powders that undergo Sifting process

Tumbing

• A process of mixing powders by shaking or rotating them in a closed container

• The method is used when two or more powders have considerable density differences

1. Bulk Powders

2. Divided Powders

Classification of Powders

Bulk Powders

Dispensed in large quantities and in bulk containers

1. Perforated

2. Sifter can

3. Aerosol container

4. Wide mouth glass jar

Types of Container used for Bulk Powders

1. Oral Powder

2. Dentifrices

3. Douche Powder

4. Dusting Powder

5. Insufflations

6. Triturations

Types of Bulk Powders

Oral Powder

Supplied as finely divided powders or effervescent granules

Finely Divided Powders

Intended to be suspended or dissolved in water or mixed with soft foods

Effervescent granules

Contains active ingredient, NaHCO3, Citric acid and Tartaric acid

Stickyness

Using Citric acid alone causes what?

Crumbling or Drying

Using Tartaric acid alone causes what?

1:2 ratio

____ ratio – Citric acid to Tartaric acid

Dentifrices

• Used for Oral hygiene

• Exist in liquid, powder, or paste form

Fluoride compounds (Stannous fluoride)

Protect the teeth against dental carries

Douche powder

• Intended to be dissolved in Tepid water prior to use

• Antiseptic or cleansing agent for a body cavity

• Most common for vaginal use

• Pass through #40 or #60 sieve eliminate agglomeration and ensure complete mixing

Wide mouth, Glass jars

Storage used for Douche powder

Dusting Powder

• Also known as Conspergents

• Locally applied non-toxic preparations intended to have no systemic action

• They may be micronized or passed through a #80 or #100 sieve

Insufflations

Finely divided powders, introduced into body cavities using Insufflator or Powder blower

Triturations

• Aka 1:10 dilutions

• Dilutions of potent powdered drugs

Divided Powders

• Also known as Chartulae or Chartula

• Powders dispensed in the form of individual doses and generally are dispensed in folded papers

• Prepared by either weighing individually or via Block and Divide method (non-potent)

1. Glassine

2. Vegetable parchment

3. Waxed paper

4. White bond paper

Types of Powder Papers

Glassine

Type of Powder paper that has glazed and transparent appearance; Moisture resistant

Vegetable parchment

Type of Powder paper that has thin and semi-opaque appearance; Moisture resistant

Waxed paper

Type of Powder paper that has transparent appearance; Waterproof

White bond paper

Type of Powder paper that has opaque appearance and has no moisture resistant property