Moisture Vapour Transmission Rate

  • To determine the moisture-permeation characteristics of the packaging system being utilized for the packing of unit dose products.
  • To evaluate and qualify the suitability of the packaging of products with the USP classification scheme to evaluate the moisture-permeation characteristics of single-unit and unit-dose packs as equipment and operator performance may affect the moisture permeation of a pack.
  • To provide a high degree of assurance that the packaging system being utilized for the packing of unit dose products are meeting the Good Packaging Practices.

  • Change in packing material and or packing change part such as blister forming/sealing roller components.
  • Change in process parameters.


Preparation of Desiccant
Dry the desiccant tablets at 110° for one hour prior to use. Use tablets weighing approximately 400 mg each. (If necessary due to limited unit dose and container size tablets weighing less than 400mg can be used).

  • Seal a sufficient number of blister strips (not less than 4 ) with a total of not less than 10 unit-dose blisters are tested with 1 pellet in each unit are tested.
  • Seal a corresponding number of empty packs, each pack containing the same number of unit-dose blisters as used in the test packs, to provide the controls.
  • Store all of the pack at 75 ± 3% relative humidity and at a temperature of 23 ± 2°C.
  • After 24 hours and at a subsequent interval specified, remove the packs from the chamber, and allow them to equilibrate for about 25 minutes.
  • Record the weights of the individual packs and return them to the chamber.
  • Weigh the control packs as a unit and divide the total weight by the number of control packs to obtain the average empty pack weight.
  • Calculate the average rate of moisture permeation in mg per day for each unit-dose blister in each pack taken by the formula.

(1 / N X) [ (WF - W I) - (CF - C I)
N: is the number of days expired in the test period (beginning after the initial 24- hour equilibration period)
X: is the number of separately sealed units per pack;
WF - WI: is the difference in mg between the final and initial weights of each test pack;
CF - CI: is the difference in mg between the average final and average initial weights of the control pack the rates being calculated to two significant figures.

[NOTE: If any indicating pellets turn pink during the procedure or if the average pellet weight increase in any pack exceeds 10% terminate the test and regard only earlier determinations as valid.]

Class A: if no pack tested exceeds 0.5 mg per day in average blister moisture permeation rate; Test period: 28 days.
Class B: if no pack tested exceeds 5 mg per day in average blister moisture permeation rate; Test period: 7 days.
Class C: if no pack tested exceeds 20 mg per day in average blister moisture permeation rate; Test period: 48 hours.
Class D: if the packs tested meet none of the above-average blister moisture permeation rates requirements. Test period: 24 hours.

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