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4. Tensile Strength
▪ Tensile strength helps understand the mechanical properties of the polymeric
patches.
▪ Tensile strength of patches is determined by clamping the patch in between
two clamps that are pulled apart.
▪ The force required for breaking the patch or nicking of the patch was
measured and is corresponded to the tensile strength of patch.

5. Percentage moisture content
▪ The pieces of a specific area from the patch are cut, weighed and dried in desiccators
containing fused anhydrous calcium chloride at ambient or slightly elevated temperature.
▪ The pieces are weighed intermittently to observe a loss in weight till constant weight is
achieved.
▪ The loss of weight in percentage seems to be corresponding to the moisture content.

6. Water Vapor Transmission (WVT)
▪ 1 g of fused anhydrous calcium chloride is weighed and placed in vials covered with a piece
of the patch and then kept in the humidity chamber maintained at 68% RH.
▪ At the end of specified time intervals, the vials are weighed again, and the weight increase is
referred as a quantity of the moisture transmitted by the patch.

7. Content uniformity
▪ The test is performed by randomly selecting 10 patches and the content of each patch is
solubilized in the specific media to extract out the drug completely.
▪ The content of each patch was quantified by suitable method (HPLC).
▪ If the content of 9 out of 10 patches is between 85% and 115% of the specified value and
the remaining patch has content from 75% to 125% of the specified value, then transdermal
patches seem to pass the test of content uniformity.

8. Evaluation of adhesive properties (Peel Adhesion Test)
▪ The force needed to peel an adhesive (patch ) off the surface where it is attached after (1 min
contact) is referred to as the peel adhesion force.
▪ Most employed test for peel adhesion consists of a substrate of stainless steel and peel
angles of 90°or 180°.

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