In the first step, the matrix that will be the basis of the patch is prepared by combining the ‘ingredients’ in a large vessel (holding 100 to 3,000 litres).
In the second step, the liquid, adhesive matrix is applied evenly to the release liner. This is important so as to ensure that precisely the same concentration of the active substance is present at every point on the LTS patch. As a result, this stage of production is rather complex and time-consuming.
The matrix is then carefully dried and fixed to the release liner.
A simple form of the patch has now been created. In the next step, the backing film is applied to the dried matrix. This creates a ‘patch’ measuring 1.5 metres across and up to 300 metres in length.
This enormous patch, called the laminate (comprising release liner, adhesive layer and backing film), is then cut to size.
The next machine punches out the shape of the patch. LTS patches can be round, oval, square – in fact, almost any shape. This optimises the efficacy and comfort for the patient.
The finished patches are then separated from one another so they can be heat-sealed into their pouches.