mixing are Tumbler mixing, Ribbon mixer, Screw mixer etc Factors that influence mixing quality such as
mixing time, speed of mixing rotation, the type of the mixer, dry or wet mixing process and so on Step.
(3) Packaging of powders:
Bulk powders for external use are often dispensed in a shaker top container to facilitate topical
application. They may also be dispensed in a wide mouth jar or a plastic container with flip-top lid. The
jar or plastic container can be closed tightly to provide increased stability and protection from light and
moisture, especially for compounds that contain volatile ingredients. Package should contain label as
“For external use only”.
Bulk powders intended for internal use should be dispensed in an amber colored widemouth
powder jar with a tight-fitting lid. They should be accompanied by an appropriately sized dosing spoon
or cup and adequate directions for removing and administering a correct dose. Bulk powders for internal
use should be labeled with the strength of the active ingredient per dose.
Powders may be wrapped in paper, weigh the required number of powders and wrap in the
papers. White glazed paper is generally used for wrapping. The wrapping should be done on a clean tile
or large sheet of a glazed paper to protect the product. In a wellwrapped powder, there should be no
powder within the flaps or folds. When powder is opened, for administration, the powdered material
should appear in the center of the paper.
Double- Wrapping
:
Double-wrapping is essential for volatile or hygroscopic drugs like Menthol, thymal, citric acid,
Pepsin etc. Double wrapping is also must for drugs those are sensitive to the atmospheric conditions.
For this purpose a wax paper is cut slightly smaller than the demy paper each way and fold both
paper at once similar to the single wrapping method
Labelling:
Patient should be instructed that individual powder should be dispersed in a little water or
placed on the back of the tongue before swallowing.
Dispensing of powders involving special problems/ problems encountered in powder formulation.
A number of problems arise while dispensing a powder containing volatile substances,
hygroscopic and deliquescent powders, eutectic mixtures, efflorescent powders, liquids, explosive
substance and potent drugs. So special consideration are done while dispensing such powders.
Volatile substances
Certain vegetable powders contain volatile oils. To prevent the loss of volatile oils, these
vegetable drugs must be powdered lightly in a mortar. Similarly the volatilization of substances like
menthol, camphor and essential oils may take place on incorporation in powders. This is prevented or at
least minimized by the use of double wrapping. The inner wrapper should be of wax paper and outer
wrapper may be of any thick paper.
Hygroscopic powders and deliquescent powder