Powders

powder

intimate mixtures of dry, finely divided drugs and/or chemicals that may be intended for internal (oral) or external (topical) use

0.1 to 10

powders consist of particles ranging in size from about 0.1 mcm to about 10,000 mcm, but the most useful pharmaceutical range is approximately 0.1 to 10 mcm

topical

____________ bulk powders are applied to the skin for local effect

internal

bulk powders for ______________ use offer a convenient method of dispensing. Ex: antacids, bulk laxatives, antidiarrheal medications, oral electrolyte mixtures

chartulae

divided powders on paper for dispensing

insufflated

_______________________ powders are finely divided powders that are intended for application in a body cavity - ears, nose, throat, tooth socket, vagina

advantages

______________ of powders:

-most stable as dry solids

-have dose flexibility

-easy to achieve fast action as no "disintegration" step is needed like a tablet

-dry, compact, and easy to store and transport

-individual units

-can be incorporated in other dosage forms

Noyes-Whitney equation

equation that describes the rate of dissolution; important for internal use of powders

sieving

determines particle size for most pharmaceutical powders; descriptive terms in terms of percent of the powder sample that will pass through a sieve of a given fineness

larger

the ______________ the sieve number, the smaller the sieve openings and therefore the smaller the particles must be able to pass through the sieve

fine

if the sieve number is large, the particles are ____________

coarse

if the sieve number is small, the particles are ____________

glass

powder compounding and trituration should be done in a ________________ (nonporous) mortar for potent materials

comminution

the process of particle size reduction; can be manual or mechanical

trituration

grinding together two or more substances in a mortar to intimately mix them to reduce particle size

pulverization

because some compounds do not lend themselves to direct trituration, ______________________ by intervention uses recrystallization as a method of obtaining fine particles.

volatile

in the pulverization process, the solid is dissolved in a minimum volume of a __________________ solvent such as alcohol. When this evaporates, finely divided particles are left behind

levigation

the process of reducing particle size of a solid by triturating it in a mortar or spatulating it (on ointment slab or pad) with a small amount of a liquid in which the solid is not soluble

homogeneous

blending methods to create a ____________________ mixture: spatulation, trituration, sifting, tumbling

geometric dilution

technique used when blending two or more powder ingredients of unequal quantities so that the small quantities of drugs are uniformly distributed

external (topical)

diluents for ________________ bulk powders are mainly starch and talc

w/w

labeling for topical bulk powders express the concentrations of active ingredients as % ___________

(units of API per g of powder)

w/v

labeling for bulk powders for internal use are expressed as the concentration of active ingredients as % __________ (weight of API per volume to be administered)

diluent

bulk powders for internal use usually do not need added _______________, but if needed, could be magnesium carbonate, light or heavy magnesium oxide, calcium carbonate, starch, and lactose

lactose

liquids are absorbed onto an inert material (carrier) such as _______________ and then geometrically introduced into the bulk of the powder

bulk

quality control for __________ powders:

compare the final weight of the preparation with the theoretical weight and examine for uniformity of color, particle size, flowability, and freedom from caking

divided

quality control for ___________ powders:

individually weight the divided papers and then compare that weight with the theoretical weight; the packets should be checked to confirm uniformity

25%

powders prepared from manufactured product should have the BUD of __________ of the time remaining on the products expiration date or 6 months (whichever is earlier)

6 months

powders prepared from USP or NF grade substances have a BUD of __________________

uniform

generally, particles of __________________ size are blended more easily

spherical

_________________ particles tend to mix more readily because they're transported more easily from areas of high concentration to lower concentration

static electricity

__________ ______________ tends to hamper blending and can be overcome by humidification of the work area or the inclusion of small quantity of sodium lauryl sulfate or something similar to neutralize charges

Eutectic

powders that are solids at room temperature form sticky/pasty or liquids when mixed together

use a bulky absorbent such as light magnesium oxide or magnesium carbonate and triturate lightly on a pill tile using a spatula

hygroscopic powders

solid drugs or chemicals that absorb moisture from the air

deliquescent powders

hygroscopic powders that may absorb sufficient moisture from air to dissolve and form solution

efflorescent powders

drugs or chemicals that contain water of hydration that may be released when the powders are manipulated or are stored under conditions of low relative humidity

become sticky or pastey or may even liquify

effervescent salts

usually mixtures of citric acid or tartaric acid, or both, combined with sodium bisphosphate or sodium carbonate, or both

powder

will rapidly effervesce when added to water and may overflow the container

granules

expose less surface area and will hydrate and dissolve more slowly, resulting in a slower, more controlled effervescence

granules

spherical, regular size particles that flow better than powders, have improved content uniformity, ease of wetting, compressibility, and decreased caking