NOTE: Prescriptions dispensed using unopened containers from the manufacturer do not need to be tested.
Material required:
(1) desiccant dried completely
(2) 10 test containers to be filled with the dried desiccant
(3) 5 control containers to be filled with a nonabsorbent filler
(4) enclosure for holding test and control containers at a constant humidity 75 +/- 3% and temperature of 23 +/- 2°C.
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Size of Container
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Filling with Desiccant or Control Material
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< 20 mL
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Fill two thirds full.
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>= 20 mL
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Fill up to a point 13 mm from the top
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If the container is > 63 mm high, it may not be necessary to completely fill the container with desiccant or control material. If the vertical height is X mm, the container can be filled with:
(1) 50 mm of filling material
(2) 13 mm of free space at the top
(3) X - 63 mm of bulk filler material
The lid for each container should be shut tightly. For containers with screw tops a specific torque is applied, ranging from 5 to 95 inch-pounds using a torque wrench (see Table page VI/27).
Parameters to measure:
(1) volume of the container in mL
(2) number of days in test period (typically 14)
(3) initial weight of container with desiccant in grams
(4) initial weight of control container in grams
(5) final weight of container with desiccant in grams
(6) final weight of control container in grams
rate of moisture permeability in mg per day per liter =
= 1000 / ((days in test period) * (volume of container in mL)) * (((final weight of desiccant container) - (initial weight of desiccant container)) - ((final weight of control container) - (initial weight of control container)))
where:
• 1,000 indicates the number of mL per liter.
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Designation
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Criteria
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tight
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no more than 1 of the 10 test containers has a rate > 100 and <= 200 mg per day per liter in moisture permeability
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well-closed
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no more than 1 of the 10 test containers has a rate > 2,000 and <= 3,000 mg per day per liter in moisture permeability
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Limitation:
• This measure assumes that the container is tightly sealed. If the patient does not close the container completely then the permeability of the container may not be critical.
