Definition of powder:
Powder are homogeneous mixture of drug/drugs and excipient/excipients in a dry, fine state of subdivision.
(BOTH ARE IN POWDERED FORM)
It includes all fillers, sweeteners, taste modifiers, adsorbents, coloring agents, flavoring agents etc.
Powder use for external purpose are called as “Dusting powders”.
Characters of good powder:
· Fine state of sub division
· A perfectly homogeneous preparation
· Small particle size, large surface area and high absorptive capacity are important character for antacid, antidiarrhoeal and other medicaments which are use for local treatment of skin and g. i. tract.
Advantages:
· Each dose can contain a different amount of active drug.
· Can be administered easily to infants and young children who cannot swallow tablets or capsules.
· Drug will have a rapid onset of action since disintegration is not required .
· Can be applied to many body cavities such as ears, nose, tooth socket, throat.
· Drugs tend to most stable as a solid. eg, Dry Antibiotic syrups. Half life of Antibiotics in solid form is about 2-3 years but once it is formulated in liquid form it reduces to 1-2 weeks. So, dry syrups are better option for those types of drugs.
· Can be made into many different dosage formulations (capsules, tablets, powders for reconstitution, dusting powders, bulk powders, powders for inhalation, etc.).
· Convenient for large dose.
Disadvantages:
Ø Masking of unpleasant taste is a big problem.
Ø Less convenient to carry as compared to tablets & capsules.
Ø Less accuracy in dispensing potent drugs in powder dosage form.
Ø We can not supply drugs in powder dosage form which are degraded in stomach.
Ø Time consuming to prepare.
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